Publications by authors named "Lianghuan Wu"

23 Publications

  • Page 1 of 1

The Fungi-specific histone Acetyltransferase Rtt109 mediates morphogenesis, Aflatoxin synthesis and pathogenicity in Aspergillus flavus by acetylating H3K9.

IMA Fungus 2021 Apr 7;12(1). Epub 2021 Apr 7.

Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.

Aspergillus flavus is a common saprophytic filamentous fungus that produces the highly toxic natural compound aflatoxin during its growth process. Synthesis of the aflatoxins, which can contaminate food crops causing huge losses to the agricultural economy, is often regulated by epigenetic modification, such as the histone acetyltransferase. In this study, we used Aspergillus flavus as an experimental model to construct the acetyltransferase gene rtt109 knockout strain (△rtt109) and its complementary strain (△rtt109·com) by homologous recombination. The growth of △rtt109 was significantly suppressed compared to the wild type (WT) strain and the △rtt109·com strain. The sclerotium of △rtt109 grew smaller, and the amount of sclerotia generated by △rtt109 was significantly reduced. The number of conidiums of △rtt109 was significantly reduced, especially on the yeast extract sucrose (YES) solid medium. The amount of aflatoxins synthesized by △rtt109 in the PDB liquid medium was significantly decreased We also found that the △rtt109 strain was extremely sensitive to DNA damage stress. Through the maize seed infection experiment, we found that the growth of △rtt109 on the surface of affected corn was largely reduced, and the amount of aerial mycelium decreased significantly, which was consistent with the results on the artificial medium. We further found that H3K9 was the acetylated target of Rtt109 in A. flavus. In conclusion, Rtt109 participated in the growth, conidium formation, sclerotia generation, aflatoxin synthesis, environmental stress response, regulation of infection of A. flavus. The results from this study of rtt109 showed data for acetylation in the regulation of life processes and provided a new thought regarding the prevention and control of A. flavus hazards.
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http://dx.doi.org/10.1186/s43008-021-00060-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8025522PMC
April 2021

The inhibition effect of tea polyphenols on soil nitrification is greater than denitrification in tea garden soil.

Sci Total Environ 2021 Mar 9;778:146328. Epub 2021 Mar 9.

Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address:

Tea polyphenols are the most widely distributed class of secondary metabolites (Camellia sinensis) and account for a considerable proportion of the pruning residues of tea. A large amount of tea polyphenols have fallen down over soil with prunning residues every year. However, the effect of tea polyphenols on soil nitrogen cycle, especially the denitrification process and its related microbial communities, remains unclear. Epigallocatechin gallate (EGCG), the most abundant component of tea polyphenols, was selected to simulate the effects of tea polyphenols on soil nitrification, denitrification, related functional genes and microbial community. The results indicated that addition of EGCG can significantly (p < 0.05) inhibit soil nitrification. Copy numbers of bacterial and archaeal ammonia monooxygenase genes (amoA) decreased as EGCG concentration increased. Further, the ammonia oxidisers exhibited a significantly (p < 0.05) greater niche differentiation under the effect of EGCG compared with the control treatment (no EGCG addition). However, the inhibition effect of EGCG over soil denitrification was most significant at 34 and 36 day of incubation period, and such inhibitory effect was more apparent on nitrification compared with denitrification. EGCG addition increased the diversity of bacterial community. The composition of bacterial community was significantly altered and community variation was primary explained by EGCG, NH-N, NO-N, soil organic carbon contents and potential denitrification rates. EGCG addition significantly increased relative abundance of Proteobacteria and Bacteroidetes phyla whereas decreased Actinobacteria. Overall, tea polyphenols can inhibit soil nitrification to a larger extent than denitrification by reducing the abundance of microorganisms carrying the related functional genes. Our results can serve as important basis of reducing the nitrogen pollution risk in tea orchards and could be considered as a powerful natural nitrification inhibitor to reduce the environmental risks caused by unreasonable nitrogen fertiliser adaptation.
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http://dx.doi.org/10.1016/j.scitotenv.2021.146328DOI Listing
March 2021

Temporal variation in nutrient requirements of tea (Camellia sinensis) in China based on QUEFTS analysis.

Sci Rep 2020 02 4;10(1):1745. Epub 2020 Feb 4.

Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.

Fertilisation datasets collected from field experiments (n = 21) in tea-producing areas from 2016 to 2018 were used to build a quantitative evaluation of the fertility of tropical soils (QUEFTS) model to estimate nutrient uptake of tea plants, and to investigate relationships between tea yield and nutrient accumulation. The production of 1000 kg spring tea (based on one bud with two young expanding leaves) required 12.2 kg nitrogen (N), 1.2 kg phosphorus (P), and 3.9 kg potassium (K), and the corresponding internal efficiencies (IEs) for N, P, and K were 82.0, 833.3, and 256.4 kg kg. To produce 1000 kg summer tea, 9.1 kg N, 0.8 kg P, and 3.1 kg K were required, and the corresponding IEs for N, P, and K were 109.9, 1250.0, and 322.6 kg kg. For autumn tea, 8.8 kg N, 1.0 kg P, and 3.2 kg K were required to produce 1000 kg tea, and the corresponding IEs for N, P, and K were 113.6, 1000.0, and 312.5 kg kg. Field validation experiments performed in 2019 suggested that the QUEFTS model can appropriately estimate nutrient uptake of tea plants at a certain yield and contribute to developing a fertiliser recommendation strategy for tea production.
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http://dx.doi.org/10.1038/s41598-020-57809-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7000836PMC
February 2020

Glutamate dehydrogenase mediated amino acid metabolism after ammonium uptake enhances rice growth under aeration condition.

Plant Cell Rep 2020 Mar 9;39(3):363-379. Epub 2019 Dec 9.

State Key Laboratory of Rice Biology, China National Rice Research Institute, No. 359 Tiyuchang Road, Hangzhou, 310006, Zhejiang, People's Republic of China.

Key Message: Aeration stimulates the rice growth and nitrogen (N) metabolism; in which, the glutamate accumulation limited by the glutamate dehydrogenase pathway after ammonia uptake may control root N metabolism during aeration. Increasing rhizosphere oxygen content greatly improves rice growth and biomass. To study the intrinsic mechanism involved in nitrogen (N) metabolism, a hydroponic experiment was conducted by supplying two different oxygen levels to two different rice genotypes. Compared to the hypoxia-resistant cultivar (Nip; japonica rice 'Nipponbare'), the hypoxia-sensitive cultivar (U502; upland rice 'Upland 502') presented with severe oxidative damage under the lack of aeration. However, aeration significantly reduced root oxidative damage by enhancing root antioxidant capacity and leaf photosynthesis especially in U502, and significantly increased nitrate (NO) and ammonia (NH) uptake and upregulated the expression of the genes controlling these processes. Additional NO was mainly incorporated into amino acids in the leaves whereas NH assimilation occurred mostly in the roots. The N gas chromatography-mass spectrometry analysis demonstrated that aeration had no influence on the compositions of the individual amino acids derived from NO in the roots, but increased labeled glutamic acid (Glu), asparagine, γ-aminobutyric acid, and alanine in NH-treated roots. Aeration inhibited root glutamate synthetase activity but this did not inhibit N-Glu production from NH. In contrast, aeration upregulated isocitrate dehydrogenase and glutamate dehydrogenase. These mechanisms and soluble carbohydrates may constitute an alternative pathway for Glu production in which amino acid metabolism is enhanced after NH uptake during aeration. Therefore, the rice growth-enhancing effect of aeration is closely correlated with root redox equilibrium, N uptake, and amino acid metabolism. Glutamic acid accumulation is limited by the glutamate dehydrogenase pathway after NH uptake and may control root N metabolism during aeration.
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http://dx.doi.org/10.1007/s00299-019-02496-wDOI Listing
March 2020

Set3 Is Required for Asexual Development, Aflatoxin Biosynthesis, and Fungal Virulence in .

Front Microbiol 2019 29;10:530. Epub 2019 Mar 29.

Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.

is an opportunistic pathogenic fungus for both plant and animal that produces carcinogenic toxins termed aflatoxins (AFs). To identify possible genetic targets to reduce AF contamination, in this study, we have characterized a novel Set3, and it shares sequence homology with the yeast protein Set3. The deletion mutants present no difference in growth rate but alterations in asexual development and secondary metabolite production when compared to the wild type. Specifically, deletion of gene decreases conidiophore formation and conidial production through downregulating expression of and genes. In addition, normal levels of are required for sclerotial development and expression of sclerotia-related genes and . Further analyses demonstrated that Set3 negatively regulates AF production as well as the concomitant expression of genes in the AF gene cluster. Importantly, our results also display that Set3 is involved in crop kernel colonization. Taking together, these results reveal that a novel Set3 plays crucial roles in morphological development, secondary metabolism, and fungal virulence in .
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http://dx.doi.org/10.3389/fmicb.2019.00530DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6455067PMC
March 2019

The HosA Histone Deacetylase Regulates Aflatoxin Biosynthesis Through Direct Regulation of Aflatoxin Cluster Genes.

Mol Plant Microbe Interact 2019 Sep 31;32(9):1210-1228. Epub 2019 Jul 31.

Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.

Histone deacetylases (HDACs) always function as corepressors and sometimes as coactivators in the regulation of fungal development and secondary metabolite production. However, the mechanism through which HDACs play positive roles in secondary metabolite production is still unknown. Here, classical HDAC enzymes were identified and analyzed in , a fungus that produces one of the most carcinogenic secondary metabolites, aflatoxin B (AFB1). Characterization of the HDACs revealed that a class I family HDAC, HosA, played crucial roles in growth, reproduction, the oxidative stress response, AFB1 biosynthesis, and pathogenicity. To a lesser extent, a class II family HDAC, HdaA, was also involved in sclerotia formation and AFB1 biosynthesis. An in vitro analysis of HosA revealed that its HDAC activity was considerably diminished at nanomolar concentrations of trichostatin A. Notably, chromatin immunoprecipitation experiments indicated that HosA bound directly to AFB1 biosynthesis cluster genes to regulate their expression. Finally, we found that a transcriptional regulator, SinA, interacts with HosA to regulate fungal development and AFB1 biosynthesis. Overall, our results reveal a novel mechanism by which classical HDACs mediate the induction of secondary metabolite genes in fungi.
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http://dx.doi.org/10.1094/MPMI-01-19-0033-RDOI Listing
September 2019

Cyclase-Associated Protein Cap with Multiple Domains Contributes to Mycotoxin Biosynthesis and Fungal Virulence in Aspergillus flavus.

J Agric Food Chem 2019 Apr 5;67(15):4200-4213. Epub 2019 Apr 5.

Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences , Fujian Agriculture and Forestry University , Fuzhou , Fujian 350002 , People's Republic of China.

In Aspergillus, the cyclic adenosine monophosphate (cAMP) signaling modulates asexual development and mycotoxin biosynthesis. Here, we characterize the cyclase-associated protein Cap in the pathogenic fungus Aspergillus flauvs. The cap disruption mutant exhibited dramatic reduction in hyphal growth, conidiation, and spore germination, while an enhanced production of the sclerotia was observed in this mutant. Importantly, the cap gene was found to be important for mycotoxin biosynthesis and virulence. The domain deletion study demonstrated that each domain played an important role for the Cap protein in regulating cAMP/protein kinase A (PKA) signaling, while only P1 and CARP domains were essential for the full function of Cap. The phosphorylation of Cap at S35 was identified in A. flavus, which was found to play a negligible role for the function of Cap. Overall, our results indicated that Cap with multiple domains engages in mycotoxin production and fungal pathogenicity, which could be designed as potential control targets for preventing this fungal pathogen.
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http://dx.doi.org/10.1021/acs.jafc.8b07115DOI Listing
April 2019

Nitric oxide synthase-mediated early nitric oxide burst alleviates water stress-induced oxidative damage in ammonium-supplied rice roots.

BMC Plant Biol 2019 Mar 20;19(1):108. Epub 2019 Mar 20.

Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.

Background: Nutrition with ammonium (NH) can enhance the drought tolerance of rice seedlings in comparison to nutrition with nitrate (NO). However, there are still no detailed studies investigating the response of nitric oxide (NO) to the different nitrogen nutrition and water regimes. To study the intrinsic mechanism underpinning this relationship, the time-dependent production of NO and its protective role in the antioxidant defense system of NH- or NO-supplied rice seedlings were studied under water stress.

Results: An early NO burst was induced by 3 h of water stress in the roots of seedlings subjected to NH treatment, but this phenomenon was not observed under NO treatment. Root oxidative damage induced by water stress was significantly higher for treatment with NO than with NH due to reactive oxygen species (ROS) accumulation in the former. Inducing NO production by applying the NO donor 3 h after NO treatment alleviated the oxidative damage, while inhibiting the early NO burst by applying the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) increased root oxidative damage in NH treatment. Application of the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester(L-NAME) completely suppressed NO synthesis in roots 3 h after NH treatment and aggravated water stress-induced oxidative damage. Therefore, the aggravation of oxidative damage by L-NAME might have resulted from changes in the NOS-mediated early NO burst. Water stress also increased the activity of root antioxidant enzymes (catalase, superoxide dismutase, and ascorbate peroxidase). These were further induced by the NO donor but repressed by the NO scavenger and NOS inhibitor in NH-treated roots.

Conclusion: These findings demonstrate that the NOS-mediated early NO burst plays an important role in alleviating oxidative damage induced by water stress by enhancing the antioxidant defenses in roots supplemented with NH.
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http://dx.doi.org/10.1186/s12870-019-1721-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6425712PMC
March 2019

Variability of leaf photosynthetic characteristics in rice and its relationship with resistance to water stress under different nitrogen nutrition regimes.

Physiol Plant 2019 Dec 15;167(4):613-627. Epub 2019 Apr 15.

State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.

The negative effects of water stress on rice can be alleviated by NH nutrition. However, the effects of mixed nitrogen (N) nutrition (NO  + NH ) on resistance to water stress are still not well known. To investigate the response of rice growth to water stress and its relationship with photosynthetic characteristics, a hydroponic experiment supplying different N forms was conducted. Compared with NO nutrition, mixed-N and NH nutrition greatly alleviated the reduction of leaf area, chlorophyll content, and photosynthesis under water stress, whilst subsequently maintaining higher biomass. In contrast, water stress inhibited the root-shoot ratios in NH - and mixed-N-supplied plants, indicating reduced root growth and higher photosynthate availability to shoots. The following key observations were made: (1) a similar stomatal limitation and low proportion of activated Rubisco were observed among the three different N nutrition regimes; (2) increased mesophyll conductance in NH - and mixed-N-supplied plants simultaneously stimulated leaf photosynthesis and improved the water use efficiency and (3), the maximum carboxylation rate and actual photochemical efficiency of photosystem II in NH - and mixed-N-supplied plants were significantly higher than that in NO -supplied plants, thus resulting in higher photochemical efficiency under water stress. In conclusion, mixed-N and NH nutrition may be used to develop strategies for improved water stress resistance and stimulated biomass production under conditions of osmotic stress and possibly drought.
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http://dx.doi.org/10.1111/ppl.12909DOI Listing
December 2019

Ammonium uptake and metabolism alleviate PEG-induced water stress in rice seedlings.

Plant Physiol Biochem 2018 Nov 31;132:128-137. Epub 2018 Aug 31.

State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. Electronic address:

Ammonium (NH) can enhance the water stress induced drought tolerance of rice seedlings in comparison to nitrate (NO) nutrition. To investigate the mechanism involved in nitrogen (N) uptake, N metabolism and transcript abundance of associated genes, a hydroponic experiment was conducted in which different N sources were supplied to seedlings growing under water stress. Compared to nitrate, ammonium prevented water stress-induced biomass, leaf SPAD and photosynthesis reduction to a significantly larger extent. Water stress significantly increased root nitrate reductase (NR) and nitrite reductase (NiR) activities, but decreased leaf NiR and glutamate synthetase (GS) activities under NO supply, causing lower nitrate content in roots and higher in leaves. In contrast, under NH supply root GS and glutamine oxoglutarate aminotransferase (GOGAT) activities were significantly decreased under water stress, but remained higher in leaves, compared to NO treatment, which was beneficial for the transport and assimilation of ammonium in leaves. N tracing assays demonstrated that rice N uptake rate and accumulation were significant reduced under water stress, but were higher in plants supplied with NH than with NO. Therefore, the formers showed higher leaf soluble sugar, proline and amino acids contents, and in turn, associated with a higher photosynthesis rate and biomass accumulation. Most genes related to NO uptake and reduction in roots and leaves were down-regulated; however, two ammonium transporter genes closely related to NH uptake (AMT1;2 and AMT1;3) were up-regulated in response to water stress. Overall, our findings suggest that ammonium supply alleviated waters tress in rice seedlings, mainly by increasing root NH uptake and leaf N metabolism.
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http://dx.doi.org/10.1016/j.plaphy.2018.08.041DOI Listing
November 2018

Investigation of Aspergillus flavus in animal virulence.

Toxicon 2018 Apr 2;145:40-47. Epub 2018 Mar 2.

Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. Electronic address:

Aspergillus flavus is a common fungal pathogen of plants, animals and humans. Recently, many genes of A. flavus have been reported involving in regulation of pathogenesis in crops, but whether these genes are involved in animal virulence is still unknown. Here, we used a previous easy-to-use infection model for A. flavus based on mouse model by intravenous inoculation of A. flavus conidia. The outcome of infections in mice model showed that A. flavus NRRL3357 and laboratory strain CA14 PTS were both in dose dependent manner and highly reproducible. The progress of disease could be monitored by mice survival and histology analysis. Fungal burden analysis indicated it was gradually decreased within 7 days after infection. Moreover, aspergillosis caused by A. flavus significantly up-regulated gene expression levels of immune response mediators, including INF-γ, TNF-α, Dectin-1 and TLR2. Furthermore, the defined deletion A. flavus strains that previously displayed virulence in crop infection were also determined in this mouse model, and the results showed comparable degrees of infection in mice. Our results suggested that intravenous inoculation of conidia could be a suitable model for testing different A. flavus mutants in animal virulence. We hope to use this model to determine distinct A. flavus strains virulence in animals and study novel therapeutic methods to help control fungus diseases in the future.
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http://dx.doi.org/10.1016/j.toxicon.2018.02.043DOI Listing
April 2018

Elevated CO levels enhance the uptake and metabolism of organic nitrogen.

Physiol Plant 2018 Apr 14;162(4):467-478. Epub 2017 Dec 14.

Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.

The effects of elevated CO (eCO ) on the relative uptake of inorganic and organic nitrogen (N) are unclear. The uptake of different N sources by pak choi (Brassica chinensis L.) seedlings supplied with a mixture of nitrate, glycine and ammonium was studied using N-labelling under ambient CO (aCO ) (350 ppm) or eCO (650 ppm) conditions. N-labelled short-term uptake and N-gas chromatography mass spectrometry (GC-MS) were applied to measure the effects of eCO on glycine uptake and metabolism. Elevated CO increased the shoot biomass by 36% over 15 days, but had little effect on root growth. Over the same period, the N concentrations of shoots and roots were decreased by 30 and 2%, respectively. Elevated CO enhanced the uptake and N contribution of glycine, which accounted for 38-44% and 21-40% of total N uptake in roots and shoots, respectively, while the uptake of nitrate and ammonium was reduced. The increased glycine uptake resulted from the enhanced active uptake and enhanced metabolism in the roots. We conclude that eCO may increase the uptake and contribution of organic N forms to total plant N nutrition. Our findings provide new insights into plant N regulation under eCO conditions.
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http://dx.doi.org/10.1111/ppl.12663DOI Listing
April 2018

Effects of glucose on the uptake and metabolism of glycine in pakchoi (Brassica chinensis L.) exposed to various nitrogen sources.

BMC Plant Biol 2017 03 2;17(1):58. Epub 2017 Mar 2.

Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.

Background: Plants can absorb amino acids as a nitrogen (N) source, and glucose is an important part of root rhizodeposition and the soil sugar pool, which participates in the regulation of plant growth and uptake. In pakchoi, the effect of glucose concentration on the glycine N uptake from a nutrient mixture composed of glycine, ammonium, and nitrate, or from a single N solution of glycine alone was studied using specific substrate N-labeling and N-gas chromatography mass spectrometry.

Results: The optimal glucose concentration for plant growth was 4.5 μM or 25 μM when supplied with glycine alone or the N mixture, respectively, and resulted in a >25% increase in seedling biomass. The addition of glucose affected the relative contribution from organic or inorganic sources to overall N uptake. When glucose was added at optimal concentrations, glycine was preferentially used as an N source, while the relative contribution from nitrate was reduced. The limiting step for glycine N contribution was active uptake in the roots in high glucose and single-N-source conditions; however, root metabolism of glycine to serine was limiting in high-glucose and mixed-N-source conditions.

Conclusions: The addition of low concentrations of glucose increased the relative uptake of organic nitrogen and reduced the uptake of nitrate, suggesting a feasible way to decrease nitrate content and increase the edible quality of vegetables.
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http://dx.doi.org/10.1186/s12870-017-1006-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5335761PMC
March 2017

Hexavalent chromium stress enhances the uptake of nitrate but reduces the uptake of ammonium and glycine in pak choi (Brassica chinensis L.).

Ecotoxicol Environ Saf 2017 May 23;139:384-393. Epub 2017 Feb 23.

Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address:

Chromium (Cr) pollution affects plant growth and biochemical processes, so, the relative uptake of glycine, nitrate, and ammonium by pak choi (Brassica chinensis) seedlings in treatments with 0mgL and 10mgL Cr (VI) were detected by substrate-specific N-labelling in a sterile environment. The short-term uptake of N-labelled sources and N-enriched amino acids were detected by gas chromatography mass spectrometry to explore the mechanism by which Cr stress affects glycine uptake and metabolism, which showing that Cr stress hindered the uptake of ammonium and glycine but increased significantly the uptake of nitrate. Cr stress did not decrease the active or passive uptake of glycine, but it inhibited the conversion of glycine to serine in pak choi roots, indicating that the metabolism of glycine to serine in roots, rather than the root uptake, was the limiting step in glycine contribution to total N uptake in pak choi. Since Cr affects the relative uptake of different N sources, a feasible way to reduce Cr-induced stress is application of selective fertilization, in particular nitrate, in pak choi cultivation on Cr-polluted soil.
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http://dx.doi.org/10.1016/j.ecoenv.2017.02.009DOI Listing
May 2017

Glycine increases cold tolerance in rice via the regulation of N uptake, physiological characteristics, and photosynthesis.

Plant Physiol Biochem 2017 Mar 12;112:251-260. Epub 2017 Jan 12.

State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006 China. Electronic address:

To investigate the response of rice growth and photosynthesis to different nitrogen (N) sources under cold stress, hydroponic cultivation of rice was done in greenhouse, with glycine, ammonium, and nitrate as the sole N sources. The results demonstrate that exposure to low temperature reduced the rice biomass and leaf chlorophyll content, but their values in the glycine-treated plants were significantly higher than in the ammonium- and nitrate-treated plants. This might be attributed to the higher N uptake rate and root area and activity in the glycine-treated plants. The glycine-treated plants also maintained high contents of soluble proteins, soluble sugars, and proline as well as enhanced antioxidant enzyme activities to protect themselves against chilling injury. Under cold stress, reduced stomatal conductance (g) and effective quantum efficiency of PSII (Φ) significantly inhibited the leaf photosynthesis; however, glycine treatment alleviated these effects compared to the ammonium and nitrate treatments. The high non-photochemical quenching (qN) and excess energy dissipative energy (E) in the glycine-treated plants were beneficial for the release of extra energy, thereby, strengthening their photochemical efficiency. We, therefore, conclude that the strengthened cold tolerance of glycine-treated rice plants was closely associated with the higher accumulation of dry matter and photosynthesis through the up-regulation of N-uptake, and increase in the content of osmoprotectants, activities of the antioxidant defense enzymes, and photochemical efficiency. The results of the present study provide new ideas for improving the plant tolerance to extreme temperatures by nutrient resource management in the cold regions.
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http://dx.doi.org/10.1016/j.plaphy.2017.01.008DOI Listing
March 2017

Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

PLoS One 2016 23;11(6):e0157979. Epub 2016 Jun 23.

Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058 China.

Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many amino acids across the elevational gradient suggests that soil amino acids likely originate from a common source or through similar biochemical processes.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0157979PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4918969PMC
July 2017

Effects of different fertilizers on the abundance and community structure of ammonia oxidizers in a yellow clay soil.

Appl Microbiol Biotechnol 2016 Aug 11;100(15):6815-6826. Epub 2016 Apr 11.

Zhejiang Aofutuo Chemical Company, Shaoxing, 312369, China.

Yellow clay paddy soil (Oxisols) is a typical soil with low productivity in southern China. Nitrification inhibitors and slow release fertilizers have been used to improve nitrogen fertilizer utilization and reduce environmental impaction of the paddy soil. However, their effects on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in paddy soil have rarely been investigated. In the present work, we compared the influences of several slow release fertilizers and nitrification inhibitors on the community structure and activities of the ammonia oxidizers in yellow clay soil. The abundances and community compositions of AOA and AOB were determined with qPCR, terminal restriction fragment length polymorphism (T-RFLP), and clone library approaches. Our results indicated that the potential nitrification rate (PNR) of the soil was significantly related to the abundances of both AOA and AOB. Nitrogen fertilizer application stimulated the growth of AOA and AOB, and the combinations of nitrapyrin with urea (NPU) and urea-formaldehyde (UF) inhibited the growth of AOA and AOB, respectively. Compared with other treatments, the applications of NPU and UF also led to significant shifts in the community compositions of AOA and AOB, respectively. NPU showed an inhibitory effect on AOA T-RF 166 bp that belonged to Nitrosotalea. UF had a negative effect on AOB T-RF 62 bp that was assigned to Nitrosospira. These results suggested that NPU inhibited PNR and increased nitrogen use efficiency (NUE) by inhibiting the growth of AOA and altering AOA community. UF showed no effect on NUE but decreased AOB abundance and shifted AOB community.
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http://dx.doi.org/10.1007/s00253-016-7502-zDOI Listing
August 2016

Light intensity affects the uptake and metabolism of glycine by pakchoi (Brassica chinensis L.).

Sci Rep 2016 Feb 17;6:21200. Epub 2016 Feb 17.

Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.

The uptake of glycine by pakchoi (Brassica chinensis L.), when supplied as single N-source or in a mixture of glycine and inorganic N, was studied at different light intensities under sterile conditions. At the optimal intensity (414 μmol m(-2) s(-1)) for plant growth, glycine, nitrate, and ammonium contributed 29.4%, 39.5%, and 31.1% shoot N, respectively, and light intensity altered the preferential absorption of N sources. The lower (15)N-nitrate in root but higher in shoot and the higher (15)N-glycine in root but lower in shoot suggested that most (15)N-nitrate uptake by root transported to shoot rapidly, with the shoot being important for nitrate assimilation, and the N contribution of glycine was limited by post-uptake metabolism. The amount of glycine that was taken up by the plant was likely limited by root uptake at low light intensities and by the metabolism of ammonium produced by glycine at high light intensities. These results indicate that pakchoi has the ability to uptake a large quantity of glycine, but that uptake is strongly regulated by light intensity, with metabolism in the root inhibiting its N contribution.
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http://dx.doi.org/10.1038/srep21200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4756379PMC
February 2016

Aerated swine lagoon wastewater: a promising alternative medium for Botryococcus braunii cultivation in open system.

Bioresour Technol 2013 Jul 17;139:190-4. Epub 2013 Apr 17.

College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China.

To understand the potential of using swine lagoon wastewater to cultivate Botryococcus braunii for biofuel production, growth characteristics of B. braunii 765 cultivated in aerated swine lagoon wastewater (ASLW) without sterilization and pH adjustment were investigated. The results showed that the alga strain could maintain competitive advantage over the 26-day cultivation. The highest dry biomass of alga grown in ASLW was 0.94 mg L(-1) at day 24, which was 1.73 times that grown in BG11 medium, an artificial medium normally used for B. braunii cultivation. And the algal hydrocarbon content was 23.8%, being more than twice that in BG11 medium. Additionally, after the 26-day cultivation, about 40.8% of TN and 93.3% of TP in ASLW were removed, indicating also good environmental benefits of algal bioremediation.
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http://dx.doi.org/10.1016/j.biortech.2013.04.036DOI Listing
July 2013

Effects of iron and zinc foliar applications on rice plants and their grain accumulation and grain nutritional quality.

J Sci Food Agric 2013 Jan 27;93(2):254-61. Epub 2012 Jun 27.

Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.

Background: Foliar sprays of iron (Fe) and zinc (Zn) fertilisers are known to be an effective way to improve Fe and Zn concentrations in rice grain. However, results can differ significantly among different rice cultivars and/or types of foliar fertiliser. In this study, several Fe-rich rice cultivars were used to identify an effective foliar fertiliser for optimal Fe and Zn enrichment of rice grain.

Results: Foliar Fe amino acid (Fe-AA) fertiliser significantly improved the Fe concentration in brown rice of most cultivars. Compared with the control, the average Fe concentration in all tested cultivars was increased by 14.5%. The average Fe concentration was increased by 32.5% when 1% (w/v) nicotianamine (NA) was added to Fe-AA, while the average Zn concentration was increased by 42.4% when 0.5% (w/v) ZnSO₄ · 7H₂O was added to Fe-AA.

Conclusion: The results suggested that NA at a suitable concentration added to Fe-AA fertiliser could accelerate Fe accumulation in rice grain. A relatively low concentration of ZnSO₄ · 7H₂O added to Fe-AA significantly increased Fe and Zn accumulation in rice grain. The study identified some useful foliar fertilisers for enhancing the levels of Fe and Zn in selected Fe-rich rice cultivars.
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http://dx.doi.org/10.1002/jsfa.5749DOI Listing
January 2013

[Physiological characteristics of nitrogen nutrition and stress-resistance of film-mulched rice in various ecological regions of Zhejiang Province].

Ying Yong Sheng Tai Xue Bao 2005 Feb;16(2):273-8

College of Environment and Resource Sciences, Zhejiang University, Hangzhou 310029, China.

The study showed that different ecological environment and cultivation system in various ecological regions of Zhejiang Province resulted in some different physiological characteristics of nitrogen nutrition and stress-resistance, especially in the aspect of NO3(-)-N and NH4+-N concentrations, between film-mulched and conventional flooded rice. Owing to the heat stress in Hangjiahu plain, the NO3(-)-N concentration of film-mulched rice decreased to some extent, but NH4+-N concentration increased markedly at tillering, jointing and booting stages, compared to conventional flooded rice. In Jinqu basin, the NO3(-)-N concentration of film-mulched rice at booting stage was higher, while the NH4+-N concentration in its roots was notably lower than those of conventional flooded rice, with NH4+-N concentration in its basal stems and leaves somewhat increased. Generally, the glutamine synthetase (GS) and nitrate reductase (NR) activities in film-mulched rice leaves were enhanced at booting stage, while malondiadehyde (MDA), soluble sugar (SS) and proline (Pro) concentrations had little changes. In conclusion, film-mulched cultivation was beneficial to the rice growth and its high yielding.
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February 2005

[A review on phytoremediation of organic contaminants].

Ying Yong Sheng Tai Xue Bao 2003 Mar;14(3):457-60

College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310029.

Plants can take up and accumulate most persistant chemicals such as PCBs and PAHs by roots. Some chemicals such as TNT, TCE, and most organic pesticides can be phytodegraded into polar metabolites, or assimilated to CO2 and water by some plants. On the other hand, more microorganisms in rhizosphere can enhance the degradation rate of organic contaminants in environment. The benefits and some issues on phytoremediation are also discussed.
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March 2003

[Effects of amino acid-N and ammonium-N on wheat seedlings under sterile culture].

Ying Yong Sheng Tai Xue Bao 2003 Feb;14(2):184-6

College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310029, China.

The dry weight, total N, and glutamate-oxaloacetate transaminase(GOT) and glutamate-pyruvate transaminase (GPT) activities in roots and leaves of wheat seedlings (Triticum aestivum) grown with ammonium sulfate or amino acids (glycine, glutamate or lysine) were studied under sterile sand culture. The results showed that both NH4(+)-N and amino acid-N could be absorbed by wheat. The total N of plant fed with NH4(+)-N was similar to that fed with amino acid-N. The dry weight of plants grown 30 days with glycine or glutamate was significantly higher than that of plants grown with NH4(+)-N or free N. The dry weight of ammonium treatment was similar to that of lysine treatment or free N. NH4(+)-N in concentration of 0.7 mmol.L-1 significantly increased GPT activity of roots, but had no significant effects on leaves or roots treated 6 h in concentration of 35.7 mmol.L-1. Different species or concentrations of amino acids had different abilities to increase the GOT or GPT activity in leaves or roots.
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February 2003