Publications by authors named "Hassan Javed Chaudhary"

41 Publications

Deciphering distinct biological control and growth promoting potential of multi-stress tolerant PM32 for potato stem canker.

Physiol Mol Biol Plants 2021 Sep 19;27(9):2101-2114. Epub 2021 Sep 19.

Department of Plant Sciences, Quaid-I-Azam University, Islamabad, 45320 Pakistan.

Plant growth-promoting rhizobacteria (PGPR) represent a set of microorganisms that play significant role in improving plant growth and controlling the phytopathogens. Unpredictable performance after the application of PGPR has been observed when these were shifted from to conditions due to the prevalence of various abiotic stress conditions. During growing period, the potato crop is subjected to a combination of biotic and abiotic stresses. a soil-borne plant pathogen, causes reduced vigor and yield of potato crop worldwide. In the current study, multi-stress-tolerant rhizobacterial strain, PM32, was isolated from field-grown potato with various plant growth promoting (PGP) traits including zinc and potassium solubilization, biological nitrogen fixation, ammonia and siderophore, as well as extracellular enzyme productions (cellulase, catalase, amylase, protease, pectinase, and chitinase). The strain PM32 exhibited a distinct potential to support plant growth by demonstrating production of indole-3-acetic acid (102.6 μM/mL), ACC-deaminase activity (1.63 μM of α-ketobutyrate/h/mg protein), and exopolysaccharides (2.27 mg/mL). By retarding mycelial growth of the strain PM32 drastically reduced pathogenicity of . The strain PM32 also suppressed the pathogenic activity significantly by impeding mycelial expansion of with inhibition co-efficient of 49.87. The PM32 also depicted significant tolerance towards salt, heavy metal (Pb), heat and drought stress. PCR based amplification of and genes coding for iturin and ACC-deaminase activity respectively indicated potential of strain PM32 for lipopeptides production and ACC deaminase enzyme activity. Results of both and pot experiments under greenhouse conditions depicted the efficiency of PM32 as a promising bio-control agent for infection together with enhanced growth of potato plants as deciphered from biomass accumulation, chlorophyll , and carotenoid contents. Therefore, it was envisioned that application of indigenous multi-stress tolerant PGPR may serve to induce biotic and abiotic stress tolerance in crops/plants for pathogen control and sustainable global food supply.

Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-021-01067-2.
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http://dx.doi.org/10.1007/s12298-021-01067-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8484416PMC
September 2021

Expression studies of stress responsive genes in cotton Gossypium hirsutum L.

Mol Biol Rep 2021 Nov 17;48(11):7077-7085. Epub 2021 Sep 17.

Faculty of Agricultural Sciences and Technologies, Sivas University of Science and Technology, Sivas, Turkey.

Background: Cotton is the world's richest source of natural fiber. Meanwhile cotton plant is top ranked stress sensitive plant thereby affecting its yield and fiber quality. But, in climate change scenario, fiber yield and quality are being affected due to environmental stresses, especially heat, drought and salinity. Present study is aimed to identify cotton genotype harboring prominently expressed stress responsive genes.

Methods: Four cotton genotypes (IUB-13, IUB-222, IUB-09 and MM-58) were evaluated under drought and salinity stress for yield traits and expression of different stress responsive genes (GhWRKY3, GhDREB2 and GhRDR6).

Results: Pronounced expression of GhWRKY3, GhDREB2and GhRDR6 was observed in cotton variety IUB-13 in stress condition (drought and salinity) as compared to control followed by IUB-222 which revealed that these genotypes might possess substantial potential to cope with environmental hazards encountered in growing season CONCLUSION: Utilization of cotton genotypes i.e., IUB-13 and IUB-222 in cotton breeding program can be very much fruitful for developing cotton genotypes adoptable to climate change.
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http://dx.doi.org/10.1007/s11033-021-06696-0DOI Listing
November 2021

Microbial detoxification of dimethoate through mediated hydrolysis by Brucella sp. PS4: molecular profiling and plant growth-promoting traits.

Environ Sci Pollut Res Int 2021 Aug 9. Epub 2021 Aug 9.

Department of Agricultural Development, Democritus University of Thrace, Orestiada, Greece.

High toxicity of dimethoate requires efficient ways for detoxification and removal of its residues in contaminated environments. Microbial remediation is a process that utilizes the degradation potential of microbes to provide a cost-effective and reliable approach for pesticide abatement. For this purpose, a dimethoate-degrading bacterium Brucella sp. was isolated from a contaminated agricultural soil sample in Multan, Pakistan. This isolate was found to tolerate up to 100 ppm of dimethoate in minimal salt medium and was further evaluated for plant growth-promoting traits. The strain gave positive results for amylase, ammonia, and catalase production, while other traits such as indole acetic acid production and potassium solubilization were also confirmed. Thus, the strain could play an important role for plant nutrient transmission in the plant rhizosphere. Optimization of growth parameters (i.e., pH and temperature) depicted the potential of PS4 to be best tolerating dimethoate, with maximum cell density at λ 600 nm. Optimum pH and temperature for growth were found to be 6 and 35 °C, respectively. Based on optimization results as well as different attributes, the rhizospheric bacterial isolate PS4 was further subjected to a batch degradation experiment under different concentrations of dimethoate (25, 50, 75, and 100 ppm). This promising dimethoate-degrading isolate was found to degrade 83% of dimethoate (at 100 ppm) within a period of 7 days. In addition, it degraded 88% of dimethoate at 50 ppm, indicating that the bacterial isolate utilized dimethoate solely as a source of energy. The strain followed the first order reaction kinetics, depicting its dependence on dimethoate as energy and carbon source. Molecular profiling further supported its role in plant growth promotion and multi-stress tolerance. This research showed that Brucella sp. is capable of degrading dimethoate, and therefore, it would be useful in the investigation of novel bioremediation techniques at pesticide-polluted sites.
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http://dx.doi.org/10.1007/s11356-021-15806-1DOI Listing
August 2021

Evaluation of virulence potential of Aspergillus tubingensis and subsequent biochemical and enzymatic defense response of cotton.

Microsc Res Tech 2021 Nov 17;84(11):2694-2701. Epub 2021 May 17.

Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

Aspergillus tubingensis is a causative known pathogen of various important crops, worldwide. The existing study was aimed to examine the virulence potential of A. tubingensis on resistant (NIA-Sadori) and susceptible (CIM-573) cultivars of cotton. For this purpose, both cultivars were inoculated with pathogen and altered morphology of diseased leaves was observed with light and scanning electron microscope. Disease severity was measured and estimated to be 68.7 and 27.1% in susceptible and resistant cultivars, respectively. To understand and compare defense mechanism of resistant and susceptible cultivars, different biochemical and enzymatic changes were observed. After the infection of A. tubingensis, increase in the concentrations of sugar, total protein, proline, phenol, and phenylalanine ammonia lyase (PAL) was more prominent in resistant cultivar, than the susceptible one. Moreover, due to increased number of dead cells, significantly higher electrolyte leakage was detected in susceptible cultivar. Principal component analysis confirmed the effect of A. tubingensis on growth attributes and various physiological and biochemical activities of cotton. These findings help us to suggest a possible role of proline content, protein content, and PAL activity in resistance mechanism of Cotton plant.
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http://dx.doi.org/10.1002/jemt.23832DOI Listing
November 2021

Elucidating Cd-mediated distinct rhizospheric and ionomic and physio-biochemical responses of two contrasting L. cultivars.

Physiol Mol Biol Plants 2021 Feb 18;27(2):297-312. Epub 2021 Feb 18.

Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad, 38000 Pakistan.

Cadmium (Cd) in soil-plant system can abridge plant growth by initiating alterations in root zones. Hydroponics and rhizoboxes are useful techniques to monitor plant responses against various natural and/or induced metal stresses. However, soil based studies are considered more appropriate in order to devise efficient food safety and remediation strategies. The present research evaluated the Cd-mediated variations in elemental dynamics of rhizospheric soil together with ionomics and morpho-physio-biochemical traits of two differentially Cd responsive maize cultivars. Cd-sensitive (31P41) and Cd-tolerant (3062) cultivars were grown in pots filled with 0, 20, 40, 60 and 80 µg/kg CdCl supplemented soil. The results depicted that the maize cultivars significantly influenced the elemental dynamics of rhizosphere as well as mineral accumulation under applied Cd stress. The uptake and translocation of N, P, K, Ca, Mg, Zn and Fe from rhizosphere and root cell sap was significantly higher in Cd stressed cv. 3062 as compared to cv. 31P41. In sensitive cultivar (31P41), Cd toxicity resulted in significantly prominent reduction of biomass, leaf area, chlorophyll, carotenoids, protein contents as well as catalase activity in comparison to tolerant one (3062). Analysis of tolerance indexes (TIs) validated that cv. 3062 exhibited advantageous growth and efficient Cd tolerance due to elevated proline, phenolics and activity of antioxidative machinery as compared to cv. 31P41. The cv. 3062 exhibited 54% and 37% less Cd bio-concentration (BCF) and translocation factors (TF), respectively in comparison to cv. 31P41 under highest Cd stress regime. Lower BCF and TF designated a higher Cd stabilization by tolerant cultivar (3062) in rhizospheric zone and its potential use in future remediation plans.
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http://dx.doi.org/10.1007/s12298-021-00936-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7907289PMC
February 2021

Characterization of bio-fabricated silver nanoparticles for distinct anti-fungal activity against sugarcane phytopathogens.

Microsc Res Tech 2021 Jul 20;84(7):1522-1530. Epub 2021 Feb 20.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

Advanced research, development, and application of silver nanoparticles is proceeding in recent times due to their incredible utilization in various fields. Present study was focused on the production, characterization, and antifungal activities of silver nanoparticles (AgNPs). An environment friendly extracellular biosynthetic approach was adopted to produce the AgNPs by using bacteria, fungi, and sugarcane husk. Agents used for reduction of silver to nanoparticles were taken from culture filtrate of plant growth promoting bacteria, Fusarium oxysporum and supernatant extract of sugarcane husk. Nanoparticles were also characterized by scanning electron microscopy (SEM). Synthesis of colloidal AgNPs was observed by UV-Visible diffused reflectance spectroscopy (UV-Vis DRS). Primary peak of surface plasmon resonance band was noticed around 339.782, 336.735, and 338.258 nm for bacterial, fungal, and sugarcane husk produced AgNPs. Structure of all biologically produced nanoparticles were crystalline cubic with nano size of 45.41, 49.06, and 42.75 nm for bacterial, fungal, and sugarcane husk-based nanoparticles, respectively as calculated by Debye-Scherrer equation using XRD. Fourier transform infrared spectroscopy (FTIR) analysis revealed the presence of various compounds that aid in the reduction, capping, and stability of AgNPs. The antifungal activity of AgNPs was also investigated for sugarcane fungal pathogens Colletotricum falcatum and Fusarium moniliforme. All nanoparticles exhibit prominent antifungal activities. Maximum zone of fungal inhibition was noticed about 18, 19, and 21 mm for C. falcatum while 21, 20, and 24 mm for F. moniliforme in case of bacterial, fungal, and plant-based nanoparticles (15 ppm), respectively. Best fungal inhibition was observed under application of sugarcane husk based AgNPs. Moreover, biologically produced AgNPs responded better towards the suppression of F. moniliforme in comparison to C. falcatum. Mentioned sources in present study can be ecofriendly nano-factories for biosynthesis of AgNPs and mankind should benefit from their commercial application.
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http://dx.doi.org/10.1002/jemt.23708DOI Listing
July 2021

Chromium retention potential of two contrasting Solanum lycopersicum Mill. cultivars as deciphered by altered pH dynamics, growth, and organic acid exudation under Cr stress.

Environ Sci Pollut Res Int 2021 Jun 29;28(22):27542-27554. Epub 2021 Jan 29.

Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.

Chromium (Cr), being a persistent toxic heavy metal, triggered the retardation of plant's metabolic processes by initiating changes in rhizospheric zone. Current study focused the Cr accumulation potential of two tomato (Solanum lycopersicum Mill.) cultivars through alterations of rhizospheric pH and exudation of organic acids together with plant's ionomics and morpho-physiological responses. Four-week-old seedlings of tomato cultivars (cv. Nakeb and cv. Nadir) were maintained in hydroponic solutions supplemented with 0, 100, 200, and 300 mg/L KCrO and a start pH of 6.0. The pH of the growth medium was monitored twice a day up to 6 days as well as mineral contents and morpho-physiological attributes were recorded by harvesting half of plants after 1 week. The remaining half plants were shifted to rhizoboxes for the collection of root exudates. After 6 days, cv. Nakeb exhibited medium acidification by 0.7 units while cv. Nadir showed basification by 0.6 units under 300 mg/L treatment. Increase in applied Cr levels enhanced the root and shoot Cr accumulation in both cultivars with concomitant reduction in growth and accumulation of nutrients (Fe, Zn, K, Mg, and Ca). However, this reduction in biomass and nutrient acquisition was predominant in cv. Nakeb as compared to cv. Nadir. The release of organic acid exudates (citric, acetic, maleic, tartaric, and oxalic acids) was also recorded higher in cv. Nadir at 300 mg/L applied Cr level. This enhanced production of organic acids caused greater retention of mineral nutrients and Cr in cv. Nadir, probably due to growth medium basification. Enhanced exudations of di- and tri- carboxylic organic acids together with accumulation of mineral nutrients are the physiological and biochemical indicators which confer this genotype a better adaptation to Cr polluted biotic systems. Furthermore, it was perceived that organic acid and rhizospheric pH variation response by studied tomato cultivars under Cr stress is an important factor to be considered in food safety and metal remediation programs.
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http://dx.doi.org/10.1007/s11356-020-12269-8DOI Listing
June 2021

Plant growth-promoting sp. strain SDA-4 confers Cd tolerance by physio-biochemical improvements, better nutrient acquisition and diminished Cd uptake in L.

Physiol Mol Biol Plants 2020 Dec 19;26(12):2417-2433. Epub 2020 Nov 19.

Department of Plant Sciences, Faculty of Biological Sciences, Quaid-I-Azam University, Islamabad, 45320 Pakistan.

Cadmium (Cd) is highly toxic metal for plant metabolic processes even in low concentration due to its longer half-life and non-biodegradable nature. The current study was designed to assess the bioremediation potential of a Cd-tolerant phytobeneficial bacterial strain sp. SDA-4, isolated, characterized and identified from Chakera wastewater reservoir, Faisalabad, Pakistan, together with spinach (as a test plant) under different Cd regimes. Spinach plants were grown with and without sp SDA-4 inoculation in pots filled with 0, 5 or 10 mg kg CdCl-spiked soil. Without sp. SDA-4 inoculation, spinach plants exhibited reduction in biomass accumulation, antioxidative enzymes and nutrient retention. However, plants inoculated with sp. SDA-4 revealed significantly augmented growth, biomass accumulation and efficiency of antioxidative machinery with concomitant reduction in proline and MDA contents under Cd stress. Furthermore, application of sp. SDA-4 assisted the Cd-stressed plants to sustain optimal levels of essential nutrients (N, P, K, Ca and Mg). It was inferred that the characterized Cd-tolerant PGPR strain, sp. SDA-4 has a potential to reduce Cd uptake and lipid peroxidation which in turn maintained the optimum balance of nutrients and augmented the growth of Cd-stressed spinach. Analysis of bioconcentration factor (BCF) and translocation factor (TF) revealed that sp. SDA-4 inoculation with spinach sequestered Cd in rhizospheric zone. Research outcomes are important for understanding morpho-physio-biochemical attributes of spinach- sp. SDA-4 synergy which might provide efficient strategies to decrease Cd retention in edible plants and/or bioremediation of Cd polluted soil colloids.
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http://dx.doi.org/10.1007/s12298-020-00900-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7772128PMC
December 2020

Serratia sp. CP-13 alleviates Cd toxicity by morpho-physio-biochemical improvements, antioxidative potential and diminished Cd uptake in Zea mays L. cultivars differing in Cd tolerance.

Ecotoxicol Environ Saf 2021 Jan 6;208:111584. Epub 2020 Nov 6.

Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad 38000, Pakistan.

Cadmium (Cd) is highly toxic for plant metabolic processes even in low concentration due to higher retention rates, longer half-life and non-biodegradable nature. The current study was designed to assess the bioremediation potential of Cd tolerant PGPR, Serratia sp. CP-13 together with two differentially Cd tolerant maize cultivars (MMRI-Yellow, Sahiwal-2002) selected amongst ten cultivars after screening. The maize cultivars were grown under different Cd treatments (0, 6, 12, 18, 24, 30 µM) in Petri plates both with and without Serratia sp. CP-13 inoculation. Treated plants were analyzed for their biomass accumulation, chlorophylls, carotenoids, proline, anthocyanin, protein, malondialdehyde (MDA), HO as well as for antioxidants (POD, SOD, CAT) and mineral elements (Ca, Mg, Zn, K, Fe, Na, Cd). The maize cultivar MMRI-Yellow (tolerant) and Sahiwal-2002 (sensitive) exhibited significant reduction in leaf area, nutrient contents, plant biomass, activity of antioxidants, total proteins, photosynthetic pigments as well as flavonoids with increased production of HO, proline, MDA and relative membrane permeability (RMP) under Cd stress. However, this reduction was cultivar specific and recorded higher in cv. Sahiwal-2002 as compared to MMRI-Yellow. Application of Serratia sp. CP-13 significantly augmented plant biomass, photosynthetic pigments, antioxidative machinery, as well as flavonoids and proline while diminishing HO RMP MDA production even under Cd stress in studied cultivars. Furthermore, CP-13 inoculation assisted the Cd stressed plants to sustain an optimal level of essential nutrients (Ca, Mg, Zn, K, Fe) except for Na and Cd which responded antagonistically. It was inferred that both inoculated maize cultivars exhibited better health and metabolism but substantial Cd tolerance was acquired by the sensitive cv. Sahiwal-2002 than the tolerant cv. MMRI-Yellow under applied Cd regimes. Furthermore, studied maize cultivars depicted maximum Cd tolerance in order of 30 < 24 < 18 < 12 < 6 < 0 µM Cd treatments under Serratia sp. CP-13 inoculation. Findings of current work highlighted the importance of Serratia sp. CP-13 and its inoculation impact on morpho-physio-biochemical attributes of maize growth under Cd dominant environment, which is likely an addition towards efficient approaches for bacterially-assisted Cd bioremediation and minimal Cd retention in edible plant parts.
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http://dx.doi.org/10.1016/j.ecoenv.2020.111584DOI Listing
January 2021

Mechanistic elucidation of germination potential and growth of Sesbania sesban seedlings with Bacillus anthracis PM21 under heavy metals stress: An in vitro study.

Ecotoxicol Environ Saf 2021 Jan 10;208:111769. Epub 2020 Dec 10.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan. Electronic address:

Soils contaminated with heavy metals such as Chromium (Cr) and Cadmium (Cd) severely impede plant growth. Several rhizospheric microorganisms support plant growth under heavy metal stress. In this study, Cr and Cd stress was applied to in vitro germinating seedlings of a Legume plant species, Sesbania sesban, and investigated the plant growth potential in presence and absence of Bacillus anthracis PM21 bacterial strain under heavy metal stress. The seedlings were exposed to different concentrations of Cr (25-75 mg/L) and Cd (100-200 mg/L) in Petri plates. Growth curve analysis of B. anthracis PM21 revealed its potential to adapt Cr and Cd stress. The bacteria supported plant growth by exhibiting ACC-deaminase activity (1.57-1.75 μM of α-ketobutyrate/h/mg protein), producing Indole-3-acetic acid (99-119 μM/mL) and exopolysaccharides (2.74-2.98 mg/mL), under heavy metal stress condition. Analysis of variance revealed significant differences in growth parameters between the seedlings with and without bacterial inoculation in metal stress condition. The combined Cr+Cd stress (75 + 200 mg/L) significantly reduced root length (70%), shoot length (24%), dry weight (54%) and fresh weight (57%) as compared to control. Conversely, B. anthracis PM21 inoculation to seedlings significantly increased (p ≤ 0.05) seed germination percentage (5%), root length (31%), shoot length (23%) and photosynthetic pigments (Chlorophyll a: 20%; Chlorophyll b: 16% and total chlorophyll: 18%), as compared to control seedlings without B. anthracis PM21 inoculation. The B. anthracis PM21 inoculation also enhanced activities of antioxidant enzymes, including superoxide dismutase (52%), peroxidase (66%), and catalase (21%), and decreased proline content (56%), electrolyte leakage (50%), and malondialdehyde concentration (46%) in seedlings. The B. anthracis PM21 inoculated seedlings of S. sesban exhibited significantly high (p ≤ 0.05) tissue deposition of Cr (17%) and Cd (16%) as compared to their control counterparts. Findings of the study suggested that B. anthracis PM21 endured metal stress through homeostasis of antioxidant activities, and positively impacted S. sesban growth and biomass. Further experiments in controlled conditions are necessary for investigating phytoremediation potential of S. sesban in metal-contaminated soils in presence of B. anthracis PM21 bacterial strain.
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http://dx.doi.org/10.1016/j.ecoenv.2020.111769DOI Listing
January 2021

Microbe-EDTA mediated approach in the phytoremediation of lead-contaminated soils using maize ( L.) plants.

Int J Phytoremediation 2021 9;23(6):585-596. Epub 2020 Nov 9.

Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

In the current study, we investigated the potential of ethylenediaminetetraacetic acid (EDTA) assisted phytoremediation potential of L. to remediate lead (Pb)-contaminated soils. The exhibited various stress tolerance mechanisms via plant growth promoting (PGP) traits, intrinsic extracellular enzyme production and antibiotic resistance. A greenhouse experiment was conducted to examine the dual effects of plant growth promoting endophytic bacteria (PGPEB)-chelator synergy in maize plants under different Pb contaminated soil regimes. -EDTA (5 mM EDTA kg) complex significantly ( < 0.05) enhanced plant growth and biomass (48.91%); chlorophyll , and carotenoid contents (27.26%, 25.02% and 42.09%); relative water content (61.33%); proline content (63.60%); root and shoot Pb accumulation capacity (52.31% and 44.71%) in Pb contaminated soils. This may suggest the efficacy of current approach in enhancing plant tolerance capability toward Pb-uptake and phytoremediation capacity. Moreover, maize plants showed differential response to Pb availability in soil-1 (S1; Pb spiked soil, 500 mg kg) and soil-2 (S2; aged-contaminated soil) under various treatments. We describe the intriguing role of -EDTA-maize system for Pb decontamination which can be used as a base line to explore the proposed combinatorial approach for long-term trails under field conditions for reclamation of Pb-contaminated soils.HighlightsThe PGPEB-EDTA mediated potential of against Pb spiked and industrial contaminated soils is noticed.Increased tolerance of against Pb in association with , and EDTA is reported first time.Enhanced accumulation of metals by is reported under combined treatment of , and EDTA.Inoculation of plants with , and EDTA has positive effects on growth and accumulation of Pb by .
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http://dx.doi.org/10.1080/15226514.2020.1842997DOI Listing
May 2021

Acinetobacter sp. SG-5 inoculation alleviates cadmium toxicity in differentially Cd tolerant maize cultivars as deciphered by improved physio-biochemical attributes, antioxidants and nutrient physiology.

Plant Physiol Biochem 2020 Oct 15;155:815-827. Epub 2020 Aug 15.

Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, 38000, Pakistan.

Cadmium is a phytotoxic metal which threatens the global food safety owing to its higher retention rates and non-biodegradable nature. Optimal study of microbe-assisted bioremediation is a potential way to minimize the adversities of Cd on plants. Current study was aimed to isolate, identify and characterize Cd tolerant PGPBs from industrially contaminated soil and to evaluate the potential of plant-microbe synergy for the growth augmentation and Cd remediation. The Acinetobacter sp. SG-5, identified through 16S rRNA gene sequence analysis, was able to tolerate 1000 mg/l of applied Cd stress and ability of in vitro indole-3-acetic acid production, phosphate solubilization, as well as 1-aminocyclopropane-1-carboxylic acid deaminase activity. A Petri plate experiment was designed to investigate the impact of Acinetobacter sp. SG-5 on applied Cd toxicity (0, 6, 12, 18, 24, 30 μM) in maize cultivars (3062-Cd tolerant, 31P41-Cd susceptible). Results revealed that non-inoculated maize plants were drastically affected with applied Cd treatments for growth, antioxidants and mineral ions acquisition predominantly in susceptible cultivar (31P41). PGPB inoculation positively influenced the maize growth by enhanced anti-oxidative potential coupled with optimum level of nutrients (K, Ca, Mg, Zn). Analysis of morpho-physio-biochemical traits after PGPB application revealed that substantial Cd tolerance was acquired by susceptible cv. 31P41 than tolerant cv. 3062 under applied Cd regimes. Research outcomes may be important for understanding the growth responses of Cd susceptible and tolerant maize cultivars under Acinetobacter sp. SG-5 inoculation and likely to provide efficient approaches to reduce Cd retention in edible plant parts and/or Cd bioremediation.
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http://dx.doi.org/10.1016/j.plaphy.2020.08.024DOI Listing
October 2020

Scanning electron microscopy of bio-fabricated Fe O nanoparticles and their application to control brown rot of citrus.

Microsc Res Tech 2021 Jan 28;84(1):101-110. Epub 2020 Aug 28.

Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

Citrus is the leading fruit crop of Pakistan and exported to different parts of the world. Due to suitable weather condition, this crop is affected by different biotic factors which seriously deteriorate its quality and quantity. During the months of November 2018 to January 2019, citrus brown rot symptoms were recurrently observed on sweet oranges in National Agricultural Research Centre (NARC), Islamabad. Causal agent of citrus brown rot was isolated, characterized, and identified as Fusarium oxysporum. For environment-friendly control of this disease, leaf extract of Azadirachta indica was used for the green synthesis of iron oxide (Fe O ) nanoparticles. These nanoparticles were characterized before their application for disease control. Fourier transform infrared spectroscopy (FTIR) of these synthesized nanoparticles described the presence of stabilizing and reducing compounds like alcohol, phenol, carboxylic acid, and alkaline and aromatic compounds. X-Ray diffraction (XRD) analysis revealed the crystalline nature and size (24 nm) of these nanoparticles. Energy dispersive X-Ray (EDX) analysis elaborated the presence of major elements in the samples. Scanning electron microscopy (SEM) confirmed the spinal shaped morphology of prepared nanoparticles. Successfully synthesized nanoparticles were evaluated for their antifungal potential. Different concentrations of Fe O nanoparticles were used and maximum mycelial inhibition was observed at 1.0 mg/ml concentration. On the basis of these findings, it could be concluded that Fe O nanoparticles, synthesized in the leaf extract of A. indica, can be successfully used for the control of brown rot of sweet oranges.
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http://dx.doi.org/10.1002/jemt.23570DOI Listing
January 2021

Plant growth promotion and enhanced uptake of Cd by combinatorial application of and EDTA on L.

Int J Phytoremediation 2020 24;22(13):1372-1384. Epub 2020 Jun 24.

Faculty of Biological Sciences, Department of Plant Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

In developing countries, Cd contamination is ubiquitous which limits agriculture productivity. The current study was designed to investigate the efficacy of plant--ethylene diamine tetraacetic acid (EDTA) and plant-microbe-chelator (PMC) synergy for enhanced plant growth and Cd-uptake potential of in industrially contaminated and cadmium (Cd) spiked soil. A pot experiment was conducted by growing seedlings either inoculated with or un-inoculated along with the application of 5mM EDTA. Plants were exposed to two levels of Cd contamination for 45days. An increase in Cd uptake was observed in inoculated with followed by EDTA treatment as compared to non-inoculated and un-treated ones. showed improved values with PMC approach for different growth parameters including root length (41%), shoot length (40%), fresh weight (59%), dry weight (49%), chlorophyll contents (49%), and relative water contents (30%). Higher tolerance index (117%) was observed for plants grown in soil spiked with 300mg kg Cd (S2). PMC application markedly enhanced Cd uptake potential of up to 12% and 68.8%, respectively, in S1 and S2 soil. While the PMC application increased Cd accumulation capacity of by 71.2% and 52.5% in S1 and S2 soil. The calculated bioaccumulation and translocation factor revealed that possess Cd uptake potential, and this ability can be significantly enhanced with PMC application.
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http://dx.doi.org/10.1080/15226514.2020.1780410DOI Listing
October 2020

Genetic Diversity, Population Structure and Marker-Trait Association for 100-Seed Weight in International Safflower Panel Using SilicoDArT Marker Information.

Plants (Basel) 2020 May 21;9(5). Epub 2020 May 21.

Department of Field Crops, Faculty of Agriculture and Natural Science, Bolu Abant Izzet Baysal University, 14030 Bolu, Turkey.

Safflower is an important oilseed crop mainly grown in the arid and semi-arid regions of the world. The aim of this study was to explore phenotypic and genetic diversity, population structure, and marker-trait association for 100-seed weight in 94 safflower accessions originating from 26 countries using silicoDArT markers. Analysis of variance revealed statistically significant genotypic effects ( < 0.01), while Turkey samples resulted in higher 100-seed weight compared to Pakistan samples. A Constellation plot divided the studied germplasm into two populations on the basis of their 100-seed weight. Various mean genetic diversity parameters including observed number of alleles (1.99), effective number of alleles (1.54), Shannon's information index (0.48), expected heterozygosity (0.32), and unbiased expected heterozygosity (0.32) for the entire population exhibited sufficient genetic diversity using 12232 silicoDArT markers. Analysis of molecular variance (AMOVA) revealed that most of the variations (91%) in world safflower panel are due to differences within country groups. A model-based structure grouped the 94 safflower accessions into populations A, B, C and an admixture population upon membership coefficient. Neighbor joining analysis grouped the safflower accessions into two populations (A and B). Principal coordinate analysis (PCoA) also clustered the safflower accessions on the basis of geographical origin. Three accessions; Egypt-5, Egypt-2, and India-2 revealed the highest genetic distance and hence might be recommended as candidate parental lines for safflower breeding programs. The mixed linear model i.e., the Q + K model, demonstrated that two DArTseq markers (DArT-45483051 and DArT-15672391) had significant association ( < 0.01) for 100-seed weight. We envisage that identified DArTseq markers associated with 100-seed weight will be helpful to develop high-yielding cultivars of safflower through marker-assisted breeding in the near future.
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http://dx.doi.org/10.3390/plants9050652DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284372PMC
May 2020

Deciphering metal toxicity responses of flax (Linum usitatissimum L.) with exopolysaccharide and ACC-deaminase producing bacteria in industrially contaminated soils.

Plant Physiol Biochem 2020 May 3;152:90-99. Epub 2020 May 3.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan. Electronic address:

Rapid industrialization is the main reason of heavy metals contamination of soil colloids and water reservoirs. Heavy metals are persistent inorganic pollutants; deleterious to plants, animals and human beings because of accumulation in food chain. The aim of the current work was to evaluate the role of indole acetic acid (IAA), exopolysaccharide (EPS) and ACC-deaminase producing plant growth promoting rhizobacteria (PGPR) i.e .B. gibsonii PM11 and B. xiamenensis PM14 in metal phytoremediation of metals, their survival and plant growth promotion potential in metal polluted environment as well as alterations in physio-biochemical responses of inoculated L. usitatissimum plants towards heavy metal toxicity. Two bacterial strains Bacillus gibsonii (PM11) and Bacillus xiamenensis (PM14), previously isolated from sugarcane's rhizosphere, were screened for metal tolerance (50 mg/l to 1000 mg/l) and plant growth promoting traits like IAA, ACC-deaminase, EPS production and nitrogen fixing ability under metal stress. The response of flax plant (Linum usitatissimum L.) was analyzed in a pot experiment containing both industrially contaminated and non-contaminated soils. Experiment was comprised of six different treatments, each with three replicates. At the end of the experiment, role of metal tolerant plant growth promoting bacterial inoculation was elucidated by analyzing the plant growth parameters, chlorophyll contents, antioxidative enzymes, and metal uptake both under standard and metal contaminated rhizospheres. Results revealed that root and shoot length, plant's fresh and dry weight, proline content, chlorophyll content, antioxidant enzymatic activity was increased in plants inoculated with plant growth promoting bacteria as compared to non-inoculated ones both in non-contaminated and industrial contaminated soils. In current study, inoculation of IAA, EPS and ACC-deaminase producing bacteria enhances plant growth and nutrient availability by minimizing metal-induced stressed conditions. Moreover, elevated phytoextraction of multi-metals from industrial contaminated soils by PGPR inoculated L. usitatissimum plants reveal that these strains could be used as sweepers in heavy metals polluted environment.
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http://dx.doi.org/10.1016/j.plaphy.2020.04.039DOI Listing
May 2020

Multi-stress tolerant PGPR Bacillus xiamenensis PM14 activating sugarcane (Saccharum officinarum L.) red rot disease resistance.

Plant Physiol Biochem 2020 Jun 16;151:640-649. Epub 2020 Apr 16.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan. Electronic address:

Sustainability in crop production has emerged as one of the most important concerns of present era's agricultural systems. Plant growth promoting bacteria (PGPB) has been characterized as a set of microorganisms used for enhancing plant growth and a tool for biological control of phytopathogens. However, the inconsistent performance of these bacteria from laboratory/greenhouse to field level has emerged due to prevailing abiotic stresses in fields. Sugarcane crop encounters a combination of biotic and abiotic stresses during its long developmental stages. Nevertheless, the selection of antagonistic PGPB with abiotic stress tolerance would be beneficial for end-user by the successful establishment of product with required effects under field conditions. Stress tolerant Bacillus xiamenensis strain (PM14) isolated from the sugarcane rhizosphere grown in the fields was examined for various PGP activities, enzyme assays, and antibiotic resistance. Strain was screened for in vitro tolerance against drought, salinity, heat stress, and heavy metal toxicity. Inhibition co-efficient of B. xiamenensis PM14 was also calculated against six phyto-pathogenic fungi, including Colletotrichum falcatum (53.81), Fusarium oxysporum (68.24), Fusarium moniliforme (69.70), Rhizoctonia solani (71.62), Macrophomina phaseolina (67.50), and Pythium splendens (77.58). B. xiamenensis is reported here for the first time as the rhizospheric bacterium which possesses resistance against 12 antibiotics and positive results for all in vitro PGP traits except HCN production. Role of 1-aminocyclopropane-1-carboxylate deaminase in the amelioration of biotic and abiotic stress was also supported by the amplification of acds gene. Moreover, in vitro and in vivo experiments revealed B. xiamenensis as the potential antagonistic PGPR and bio-control agent. Results of greenhouse experiment against sugarcane red rot indicated that inoculation of B. xiamenensis to sugarcane plants could suppress the disease symptoms and enhance plant growth. Augmented production of antioxidative enzymes and proline content may lead to the induced systemic resistance against red rot disease of sugarcane. Thus, the future application of native multi-stress tolerant bacteria as bio-control agents in combination with current heat, drought, salinity, and heavy metal tolerance strategy could contribute towards the global food security.
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http://dx.doi.org/10.1016/j.plaphy.2020.04.016DOI Listing
June 2020

Resistance associated metabolite profiling of Aspergillus leaf spot in cotton through non-targeted metabolomics.

PLoS One 2020 12;15(2):e0228675. Epub 2020 Feb 12.

Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

Aspergillus tubingensis is an important pathogen of economically important crops. Different biotic stresses strongly influence the balance of metabolites in plants. The aim of this study was to understand the function and response of resistance associated metabolites which, in turn are involved in many secondary metabolomics pathways to influence defense mechanism of cotton plant. Analysis of non-targeted metabolomics using ultra high performance liquid chromatography-mass spectrometry (UPLC-MS) revealed abundant accumulation of key metabolites including flavonoids, phenylpropanoids, terpenoids, fatty acids and carbohydrates, in response to leaf spot of cotton. The principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and partial least squares discriminant analysis (PLS-DA) score plots illustrated the evidences of variation between two varieties of cotton under mock and pathogen inoculated treatments. Primary metabolism was affected by the up regulation of pyruvate and malate and by the accumulation of carbohydrates like cellobiose and inulobiose. Among 241 resistance related (RR) metabolites, 18 were identified as resistance related constitutive (RRC) and 223 as resistance related induced (RRI) metabolites. Several RRI metabolites, identified in the present study were the precursors for many secondary metabolic pathways. These included phenylpropanoids (stilbenes and furanocoumarin), flavonoids (phlorizin and kaempferol), alkaloids (indolizine and acetylcorynoline) and terpenoids (azelaic acid and oleanolic acid). Our results demonstrated that secondary metabolism, primary metabolism and energy metabolism were more active in resistant cultivar, as compared to sensitive cultivar. Differential protein and fatty acid metabolism was also depicted in both cultivars. Accumulation of these defense related metabolites in resistant cotton cultivar and their suppression in susceptible cotton cultivar revealed the reason of their respective tolerance and susceptibility against A. tubingensis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0228675PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7015376PMC
April 2020

Characterization and phytostimulatory activity of bacteria isolated from tomato (Lycopersicon esculentum Mill.) rhizosphere.

Microb Pathog 2020 Mar 3;140:103966. Epub 2020 Jan 3.

Department of Plant Sciences Quaid-i-Azam University Islamabad, Pakistan. Electronic address:

Replacing agrochemicals with plant growth promoting bacteria (PGPB) may offset some of the environmental impacts of food production. The objectives of this study were to (1) isolate and characterize bacterial strains from tomato rhizosphere, including root, shoot and leaf, (2) select and identify the most promising PGPB strains, (3) verify the phytostimulatory activity and mineral uptake potential of selected strains. Bacterial strains isolated from tomato rhizosphere, were screened for phosphorous (P) solubilization, production of indole acetic acid (IAA), amylase activity, antibiotic resistance, and quick test strip (QTS) for biochemical characterization. The tested strains, positive for all five of these assays were selected for molecular identification and subjected to greenhouse growth trails with tomato and mung bean. Two strains were selected and identified as Bacillus cereus (B. cereus) isolated from rhizosphere and Klebsiella variicola (K. variicola) isolated from root endosphere using 16s rRNA sequences. Both strains produced IAA, gibberellic acid (GA3) and kinetin, however B. cereus showed potential GA3 and IAA production as compared to K. variicola. In tomato, only one growth variable (shoot length) was increased over the control by one of the selected bacterial strains (B. cereus). In mung bean, inoculation with either strain B. cereus or K. variicola increased shoot length and dry weight. Moreover, our results showed that the use of PGPB significantly increased plant growth and Fe, Zn, Ca, Mg, Cu, Na and K contents of plants. It seems that evaluated strains had a higher ability in boosting plant growth and higher yield.
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http://dx.doi.org/10.1016/j.micpath.2020.103966DOI Listing
March 2020

Assisted phytoremediation of chromium spiked soils by Sesbania Sesban in association with Bacillus xiamenensis PM14: A biochemical analysis.

Plant Physiol Biochem 2020 Jan 13;146:249-258. Epub 2019 Nov 13.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan. Electronic address:

Due to anthropogenic activities, chromium (Cr) contamination is ubiquitous with deleterious effects on plant and soil microbiota. Present study was designed to address beneficial effects of Bacillus xiamenensis PM14 on Sesbania sesban. Its physiological and biochemical attributes along with enhanced antioxidant enzyme activities under different levels of Cr toxicity (50, 100 and 200 mg kg) were evaluated. After harvesting at 50 days of sowing, plant growth attributes (root and shoot length, fresh and dry weight), physiological parameters (chlorophyll a, b and carotenoid content), antioxidant activities (superoxide dismutase, peroxidase and catalase), malondialdehyde content, electrolyte leakage, proline, relative water content and total Cr uptake in S. sesban were recorded. Experiment was statistically managed as complete randomized design (CRD). Results revealed that Cr stress reduced plant growth, relative water content at all levels of Cr contamination. However, inoculation of B. xiamenensis PM14 positively influence all parameters of S. sesban both under normal and stressed conditions. Inoculation of B. xiamenensis PM14 promoted plant growth (root length 17.08%, shoot length 28.36%) physiological attributes (chlorophyll a 55.26%, chlorophyll b 59.13%), antioxidant activities (superoxide dismutase 30.09%, peroxidase 6.96% and catalase 0.89%), relative water content 25.79%, enhanced total Cr uptake 47.33% and reduced proline 12.33%, malondialdehyde content 27.53% and electrolyte leakage 2.73% in S. sesban at 200 mg kg Cr stress as compared to uninoculated plants grown under the same level of Cr. Our findings revealed first report of B. xiamenensis as phytoremediator and its inoculation on Sesbania plant. It also exposed dual effects of B. xiamenensis to ameliorate Cr stress along with improved plant growth and induced heavy metal stress tolerance in spiked soils.
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http://dx.doi.org/10.1016/j.plaphy.2019.11.010DOI Listing
January 2020

Microbial diversity response in thallium polluted riverbank soils of the Lanmuchang.

Ecotoxicol Environ Saf 2020 Jan 31;187:109854. Epub 2019 Oct 31.

Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.

Thallium (Tl) is a toxic element, but little is known about microbial communities' response to TI mobilization and sequestration. Here, we characterize the microbial communities and their feedbacks to Tl-pollution in riverbank soils to understand the distribution of microbial metal tolerance. These soils have been affected by pollution sourced from a Tl-rich mineralized area in Lanmuchang, Guizhou, China. In all studied soil samples, Proteobacteria, Acidobacteria, and Actinobacteria were revealed relatively in higher abundance at the phylum level. The results indicated that a number of microbial communities including Gemmatimonadetes, and Actinobacteria were correlated with total Tl, suggesting potential roles of these microbes to Tl tolerance. The patterns of phylogenetic beta-diversity in studied samples showed a high diversity of the microbial community in soils with high Tl concentrations. Sequence analysis of microbial community indicated that most of the environmental parameters in soils were associated with the major phylogenetic groups such as Gemmobacteria, Bryobacteria, Proteobacteria, Actinobacteria, Firmicutes, and Rhodobacteria. Some species of microbes, Nocardioides (genus), Actinomycetales (Order), Ralstonia (phyla) and Sphingomonas (genus) might are tolerant of Tl. These results provide direction to the microbial communities in the presence of elevated Tl concentration in Lanmuchang and shed light on bioremediation of Tl polluted locations.
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http://dx.doi.org/10.1016/j.ecoenv.2019.109854DOI Listing
January 2020

The effect of lead pollution on nutrient solution pH and concomitant changes in plant physiology of two contrasting Solanum melongena L. cultivars.

Environ Sci Pollut Res Int 2019 Nov 25;26(33):34633-34644. Epub 2019 Oct 25.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.

Lead (Pb) is highly toxic to plants because it severely affects physiological processes by altering nutrient solution pH. The current study elucidated Pb-induced changes in nutrient solution pH and its effect on physiology of two Solanum melongena L. cultivars (cv. Chuttu and cv. VRIB-13). Plants were grown in black plastic containers having 0, 15, 20, and 25 mg L PbCl in nutrient solutions with starting pH of 6.0. pH changes by roots of S. melongena were continuously monitored for 8 days, and harvested plants were analyzed for physiological and biochemical attributes. Time scale studies revealed that cv. Chuttu and cv. VRIB-13 responded to Pb stress by causing acidification and alkalinization of growth medium during the first 48 h, respectively. Both cultivars increased nutrient solution pH, and maximum pH rise of 1.21 units was culminated by cv. VRIB-13 at 15 mg L Pb and 0.8 units by cv. Chuttu at 25 mg L Pb treatment during the 8-day period. Plant biomass, photosynthetic pigments, ascorbic acid, total amino acid, and total protein contents were significantly reduced by Pb stress predominantly in cv. Chuttu than cv. VRIB-13. Interestingly, chlorophyll contents of cv. VRIB-13 increased with increasing Pb levels. Pb contents of roots and shoots of both cultivars increased with applied Pb levels while nutrient (Ca, Mg, K, and Fe) contents decreased predominately in cv. Chuttu. Negative correlations were identified among Pb contents of eggplant roots and shoots and plant biomasses, leaf area, and free anthocyanin. Taken together, growth medium alkalinization, lower root to shoot Pb translocation, and optimum balance of nutrients (Mg and Fe) conferred growth enhancement, ultimately making cv. VRIB-13 auspicious for tolerating Pb toxicity as compared with cv. Chuttu. The research outcomes are important for devising metallicolous plant-associated strategies based on plant pH modulation response and associated metal uptake to remediate Pb-polluted soil.
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http://dx.doi.org/10.1007/s11356-019-06575-zDOI Listing
November 2019

Residual effects of biochar and phosphorus on growth and nutrient accumulation by maize (Zea mays L.) amended with microbes in texturally different soils.

Chemosphere 2020 Jan 4;238:124710. Epub 2019 Sep 4.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.

The purpose of study was to examine the residual effects of two types of biochar amendments, two phosphorus (P) fertilizer levels, phosphorus solubilizing bacteria (PSB) and arbuscular mycorrhizal fungs (AMF) on plant growth, nutrients absorption and root architecture of Zea mays L. in texturally different soils. Biochar signficantly increased nutrients absorption and plant biomass production with P-fertilization and microbial inoculantion. Texturally different soils enhanced the plant biomass and nutrients absorption in their independent capacity on addition of biochar, microbial inoculants and P-fertilization. It was shown that mycorrhizal inoculation had positive influence on plant root and shoot biomass in both soils irrespective to the biochar type used. Root colonization was notably increased in biochar + mycorrhizae (B + M) inocultaed plants. It was shown that mycorrhizal inoculation had positive influence on nutrients absorption by plant roots and it had high content of P, potassium, calcium and magnesium in plants at all biochar and P levels. Without P fertilization, biochar amendments significantly promoted shoot P content and root colonization. The P application significantly influenced soil microbial activity in terms of nutrient concentration and plant growth. Root attributes were significantly inclined by microbial inoculation. Residual effects of biochar and P significantly enhanced the nutreints absorption and maize plant growth. Thus, we concluded that residual biochar and P fertilizer showed positive effects on nutrients absorption and maize plant growth promotion in differently textured soils. Microbial inoculants further stimulated the plant biomass production and nutrients absorption due to effective root colonization.
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http://dx.doi.org/10.1016/j.chemosphere.2019.124710DOI Listing
January 2020

Mechanistic elucidation of germination potential and growth of wheat inoculated with exopolysaccharide and ACC- deaminase producing Bacillus strains under induced salinity stress.

Ecotoxicol Environ Saf 2019 Nov 10;183:109466. Epub 2019 Aug 10.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan. Electronic address:

The potential of plant growth regulating microorganisms present in the soil can be explored towards the purpose of identifying salt tolerant strategies and crop cultivars. Current study was designed to elucidate the capabilities of salt stress tolerant plant growth promoting rhizobacteria (PGPR) Bacillus siamensis (PM13), Bacillus sp. (PM15) and Bacillus methylotrophicus (PM19) in undermining the effects of salt stress on wheat seedling. Strains were characterized for their IAA (81-113 μM/ml), ACC-deaminase (0.68-0.95 μM/mg protein/h) and exopolysaccharide (EPS) (0.62-0.97 mg/ml) producing activity both under normal and NaCl stressed conditions. Effects of bacterial inoculation on germination and seedling growth of wheat variety Pakistan-13 was observed under induced salinity stress levels (0, 4, 8, 16 dS/m). All the morpho-physiological characteristics of wheat seedlings were affected drastically by the NaCl stress and the growth parameters expressed a negative relationship with increased NaCl levels. PGPR application had a very positive influence on germination rate of wheat seedlings, root and shoot length, photosynthetic pigments etc. Elongated roots and enhanced vegetative shoot growth as well as seedling's fresh and dry weights were highest in plants treated with B. methylotrophicus PM19. Sequestration of Na ion by EPS production and degradation of exuded ACC into a-ketobutyrate and ammonia by ACCD bacteria efficiently reduced the impact of salinity stress on wheat growth. Current findings suggested that the used PGPR strains are potential candidates for improving crop growth in salt stressed agricultural systems. However further research validation would be necessary before large scale/field application.
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http://dx.doi.org/10.1016/j.ecoenv.2019.109466DOI Listing
November 2019

Potential impact of biochar types and microbial inoculants on growth of onion plant in differently textured and phosphorus limited soils.

J Environ Manage 2019 Oct 3;247:672-680. Epub 2019 Jul 3.

Department of Soil Science and Plant Nutrition, Cukurova University, Adana, 1150, Turkey. Electronic address:

Non-renewable phosphorus (P) resources are intensively declining and recyclable P is high in demand for agricultural sector. Biochar as a renewable source of P and its physicochemical properties may improve the nutrients condition in the soil for plant availability. This study was designed to evaluate the interaction of biochar with soil microbes in differently textured and P-limited soils for P availability, root colonization and nutrient uptake by plants. Onion plants were grown in two differently textured soils with two types of biochar, with or without P application, three microbially inoculated treatments and uninoculated control. Plants were grown for 65 days and root-shoot biomass, nutrient concentration and mycorrhizal root colonization were analyzed. The WinRhizo was used to evaluate root attributes such as length, surface area and volume of roots. Biochar addition enhanced the nutrient uptake and plant biomass in the presence of P and microbial inoculants. Root colonization was notably increased in biochar + mycorrhizal inoculated plants. Biochar and soil type interactions may develop a unique behavior of nutrient uptake, root colonization, plant growth and root attributes. Biochar in combination with microbial inoculants could be considered a potentially renewable source of P fertilizer.
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http://dx.doi.org/10.1016/j.jenvman.2019.06.123DOI Listing
October 2019

Effects of Rhizophagus clarus and biochar on growth, photosynthesis, nutrients, and cadmium (Cd) concentration of maize (Zea mays) grown in Cd-spiked soil.

Environ Sci Pollut Res Int 2019 Jul 18;26(20):20689-20700. Epub 2019 May 18.

Department of Soil Science and Plant Nutrition, Cukurova University, 1150, Adana, Turkey.

Cadmium (Cd) toxicity in agricultural crops is a widespread problem. Little is known about biochar and arbuscular mycorrhizal fungi (AMF) effect on Cd concentration in maize plant either applied separately or in combination. Current study was performed to demonstrate effects of biochar and Rhizophagus clarus on plant growth, photosynthesis activity, nutrients (P, Ca, Mg, Fe, Cu, and Mn), and Cd concentration in maize grown in Cd-spiked soil. The alkaline soil was spiked by Cd factor at three levels: 0 (Cd 0), 5 (Cd 5), and 10 (Cd 10) mg/kg; biochar factor at two levels: 0 and 1%; and mycorrhizal inoculum factor at two levels: MF0 and MF1 (R. clraus). Plants were harvested after 70 days of seed germination, and various morphological and physiological parameters, as well as elemental concentration and root colonization, were recorded. Addition of biochar increased plant biomass by 21% (Cd 5) and 93% (Cd 10), MF1 enhanced by 53% (Cd 0) and 69% (Cd 10), while biochar + MF1 enhanced dry plant biomass by 70% (Cd 0) and 94% (Cd 10). Results showed maximum increase of 94% (Cd 10) in plant biomass was observed in Cd-spiked soil. Root colonization decreased proportionally by increasing Cd concentration and at Cd 10, colonization was 36.7% and 31.7% for MF1 and biochar + MF1 treatments, respectively. Besides that, addition of biochar enhanced root attributes (root length, volume, and surface area) by 34-58% compared to control in Cd 10. The MF1 increased these attributes by 11-78% while biochar + MF1 enhanced by 32-61% in Cd-spiked soil. However, biochar + MF1 neutralized Cd stress in maize plant for gaseous attributes (assimilation rate, transpiration rate, intercellular CO, and stomatal conductance). The MF1 enhanced Cd concentration in plant as it was 3.32 mg/kg in Cd 5 and 6.73 mg/kg in Cd 10 treatments while addition of biochar phytostabilized Cd and reduced its concentration in plants by 2.0 mg/kg in Cd 5 and 4.27 mg/kg in Cd 10. The biochar + MF1 had 2.9 mg/kg and 4.8 mg/kg Cd concentration in Cd 5 and Cd 10 plants, respectively. Phosphorus concentration was augmented in shoots (up to 26%) and roots (up to 20%) of maize plant in biochar-amended soil than control plants. In biochar + MF1, concentration of P was 1.01% and 0.73% in Cd 5 and Cd 10, respectively. It is concluded that biochar + MF1 treatment enhances plant biomass while addition of sole biochar reduced Cd uptake, slightly indifferent to earlier treatment.
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http://dx.doi.org/10.1007/s11356-019-05323-7DOI Listing
July 2019

Induction of tolerance to salinity in wheat genotypes by plant growth promoting endophytes: Involvement of ACC deaminase and antioxidant enzymes.

Plant Physiol Biochem 2019 Jun 1;139:569-577. Epub 2019 Apr 1.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan. Electronic address:

Plant growth-promoting endophytes (PGPEs) can colonize the internal tissues of plants and are capable of promoting plant growth. These bacteria can improve plant tolerance against various biotic and abiotic stresses via the expression of antioxidant enzymes and the production of 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Two salt-tolerant PGPEs, Kocuria rhizophila: KF875448 (14ASP) and Cronobacter sakazakii: KM042090 (OF115), with ACC deaminase activity were investigated for their potential to ameliorate plant salinity stress. The wheat varieties Pasban 90 and Khirman were subjected to two levels of salt stress (80 and 160 mM NaCl) under greenhouse conditions by using a completely randomized design. Analyses of plant growth parameters, antioxidant enzyme activities, chlorophyll and plant mineral contents were conducted to investigate the stress tolerance induced by the PGPEs. The ACC utilization by the PGPEs directly relates to the promotion of plant growth due to the lowering of excess ethylene production under salt stress. High levels of NaCl exhibited negative effects in both varieties. However, inoculation with PGPEs increased the morphological traits and antioxidant activities of the plants while decreasing the Na contents in all treatments compared to uninoculated treatment. Wheat variety Pasban 90 was more tolerant than Khirman in to salt stress in all the measured morphological and biochemical parameters, while the bacterial strain OF115 performed significantly better in all morphological and biochemical parameters, such as fresh dry weight, root shoot length, proline and chlorophyll contents, compared to strain 14ASP. The K/Na ratio in the tissues of bacterial treated plants was higher than the control, probably in order to maintain the nutrient balance. The results of our study revealed that the inoculation of plants by ACC deaminase-producing PGPEs is a potential tool for the enhancement of plant growth and stress tolerance. Moreover, endophytic bacteria allied with host plants are capable of enduring high saline conditions and can interact with plants in a very efficient way.
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http://dx.doi.org/10.1016/j.plaphy.2019.03.041DOI Listing
June 2019

Mobile genomic element diversity in world collection of safflower (Carthamus tinctorius L.) panel using iPBS-retrotransposon markers.

PLoS One 2019 26;14(2):e0211985. Epub 2019 Feb 26.

Department of Field Crops, Faculty of Agricultural and Natural Science, Bolu Abant Izzet Baysal University, Bolu, Turkey.

Safflower (Carthamus tinctorius L.) is a multipurpose crop of dry land yielding very high quality of edible oil. Present study was aimed to investigate the genetic diversity and population structure of 131 safflower accessions originating from 28 different countries using 13 iPBS-retrotransposon markers. A total of 295 iPBS bands were observed among which 275 (93.22%) were found polymorphic. Mean Polymorphism information content (0.48) and diversity parameters including mean effective number of alleles (1.33), mean Shannon's information index (0.33), overall gene diversity (0.19), Fstatistic (0.21), and inbreeding coefficient (1.00) reflected the presence of sufficient amount of genetic diversity in the studied plant materials. Analysis of molecular variance (AMOVA) showed that more than 40% of genetic variation was derived from populations. Model-based structure, principal coordinate analysis (PCoA) and unweighted pair-group method with arithmetic means (UPGMA) algorithms clustered the 131 safflower accessions into four main populations A, B, C, D and an unclassified population, with no meaningful geographical origin. Most diverse accessions originated from Asian countries including Afghanistan, Pakistan, China, Turkey, and India. Four accessions, Turkey3, Afghanistan4, Afghanistan2, and Pakistan24 were found most genetically distant and might be recommended as a candidate parents for breeding purposes. The findings of this study are most probably supported by the seven similarity centers hypothesis of safflower. This is a first study to explore the genetic diversity and population structure in safflower accessions using the iPBS-retrotransposon markers. The information provided in this work will therefore be helpful for scientists interested in safflower breeding.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0211985PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391045PMC
November 2019

Cadmium spiked soil modulates root organic acids exudation and ionic contents of two differentially Cd tolerant maize (Zea mays L.) cultivars.

Ecotoxicol Environ Saf 2017 Jul 27;141:216-225. Epub 2017 Mar 27.

Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm 10691, Sweden.

Our earlier work described that the roots of two maize cultivars, grown hydroponically, differentially responded to cadmium (Cd) stress by initiating changes in medium pH depending on their Cd tolerance. The current study investigated the root exudation, elemental contents and antioxidant behavior of the same maize cultivars [cv. 3062 (Cd-tolerant) and cv. 31P41 (Cd-sensitive)] under Cd stress. Plants were maintained in a rhizobox-like system carrying soil spiked with Cd concentrations of 0, 10, 20, 30, 40 and 50 μmol/kg soil. The root and shoot Cd contents increased, while Mg, Ca and Fe contents mainly decreased at higher Cd levels, and preferentially in the sensitive cultivar. Interestingly, the K contents increased in roots of cv. 3062 at low Cd treatments. The Cd stress caused acidosis of the maize root exudates predominantly in cv. 3062. The concentration of various organic acids was significantly increased in the root exudates of cv. 3062 with applied Cd levels. This effect was diminished in cv. 31P41 at higher Cd levels. Cd exposure increased the relative membrane permeability, anthocyanin (only in cv. 3062), proline contents and the activities of peroxidases (POD) and superoxide dismutase (SOD). The only exception was the catalase activity, which was diminished in both cultivars. Root Cd contents were positively correlated with the secretion of acetic acid, oxalic acid, glutamic acid, citric acid, and succinic acid. The antioxidants like POD and SOD exhibited a positive correlation with the organic acids under Cd stress. It is likly that a high exudation of dicarboxylic organic acids improves nutrient uptake and activities of antioxidants, which enables the tolerant cultivar to acclimatize in Cd polluted environment.
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http://dx.doi.org/10.1016/j.ecoenv.2017.03.027DOI Listing
July 2017

Influence of endophytic Bacillus pumilus and EDTA on the phytoextraction of Cu from soil by using Cicer arietinum.

Int J Phytoremediation 2017 Jan;19(1):14-22

a Department of Plant Sciences , Faculty of Biological Sciences, Quaid-i-Azam University , Islamabad , Pakistan.

In developing countries, soil contamination with metals is ubiquitous, which poses a serious threat to the ecosystem. The current study was designed to screen out the nested belongings of Cicer arietinum plants and Bacillus pumilus (KF 875447) in extracting copper (Cu) from contaminated soils. A pot experiment was executed by growing C. arietinum seedlings either inoculated with B. pumilus or uninoculated along with the application of 5 mM ethylenediaminetetraacetic acid (EDTA). Plants were subjected to three different concentrations of Cu (250, 350, and 500 ppm) for 48 days. An increase in Cu uptake was observed in C. arietinum plants inoculated with B. pumilus as compared to uninoculated ones. C. arietinum exhibited improved values for different growth parameters in the presence of B. pumilus, that is, root length (37%), shoot length (31%), whole plant fresh as well as (45%) dry weight (27%), and chlorophyll contents (32%). More than 70% of tolerance index (TI) was observed for plants at 500 ppm Cu treatment. Addition of B. pumilus and EDTA significantly increased metal uptake by C. arietinum up to 19 and 36%, respectively, while the application of B. pumilus and EDTA in combination increased metal accumulation by 41%. The calculated bioaccumulation and translocation factor (TF) revealed that C. arietinum possess phytoextraction potential for Cu, and this ability is significantly improved with application of B. pumilus and EDTA amendments.
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http://dx.doi.org/10.1080/15226514.2016.1216075DOI Listing
January 2017
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