Publications by authors named "Tianxing Lv"

13 Publications

  • Page 1 of 1

Temporal metabolite responsiveness of microbiota in the tea plant phyllosphere promotes continuous suppression of fungal pathogens.

J Adv Res 2022 07 18;39:49-60. Epub 2021 Oct 18.

College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, China. Electronic address:

Introduction: A broad spectrum of rhizosphere bacteria and fungi were shown to play a central role for health, fitness and productivity of their host plants. However, implications of host metabolism on microbiota assembly in the phyllosphere and potential consequences for holobiont functioning were sparsely addressed. Previous observations indicated that tea plants might reduce disease occurrence in various forests located in their proximity; the underlying mechanisms and potential implications of the phyllosphere microbiota remained elusive.

Objectives: This study aimed atdeciphering microbiome assembly in the tea plant phyllosphere throughout shoot development as well as elucidating potential implications of host metabolites in this process. The main focus was to explore hidden interconnections between the homeostasis of the phyllosphere microbiome and resistance to fungal pathogens.

Methods: Profiling of host metabolites and microbiome analyses based on high-throughput sequencing were integrated to identify drivers of microbiome assembly throughout shoot development in the phyllosphere of tea plants. This was complemented by tracking of beneficial microorganisms in all compartments of the plant. Synthetic assemblages (SynAss), bioassays and field surveys were implemented to verify functioning of the phyllosphere microbiota.

Results: Theophylline and epigallocatechin gallate, two prevalent metabolites at the early and late shoot development stage respectively, were identified as the main drivers of microbial community assembly. Flavobacterium and Myriangium were distinct microbial responders at the early stage, while Parabacteroides and Mortierella were more enriched at the late stage. Reconstructed, stage-specific SynAss suppressed various tree phytopathogens by 13.0%-69.3% in vitro and reduced disease incidence by 8.24%-41.3% in vivo.

Conclusion: The findings indicate that a functional phyllosphere microbiota was assembled along with development-specific metabolites in tea plants, which continuously suppressed prevalent fungal pathogens. The insights gained into the temporally resolved metabolite response of the tea plant microbiota could provide novel solutions for disease management.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jare.2021.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9263646PMC
July 2022

NUCLEOCYTOPLASMIC shuttling of ETHYLENE RESPONSE FACTOR 5 mediated by nitric oxide suppresses ethylene biosynthesis in apple fruit.

New Phytol 2022 06 23;234(5):1714-1734. Epub 2022 Mar 23.

Key Laboratory of Fruit Postharvest Biology (Liaoning Province), Key Laboratory of Protected Horticulture (Ministry of Education), National & Local Joint Engineering Research Center of Northern Horticultural Facilities Design & Application Technology (Liaoning), College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China.

Nitric oxide (NO) is known to modulate the action of several phytohormones. This includes the gaseous hormone ethylene, but the molecular mechanisms underlying the effect of NO on ethylene biosynthesis are unclear. Here, we observed a decrease in endogenous NO abundance during apple (Malus domestica) fruit development and exogenous treatment of apple fruit with a NO donor suppressed ethylene production, suggesting that NO is a ripening suppressor. Expression of the transcription factor MdERF5 was activated by NO donor treatment. NO induced the nucleocytoplasmic shuttling of MdERF5 by modulating its interaction with the protein phosphatase, MdPP2C57. MdPP2C57-induced dephosphorylation of MdERF5 at Ser260 is sufficient to promote nuclear export of MdERF5. As a consequence of this export, MdERF5 proteins in the cytoplasm interacted with and suppressed the activity of MdACO1, an enzyme that converts 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. The NO-activated MdERF5 was observed to increase in abundance in the nucleus and bind to the promoter of the ACC synthase gene MdACS1 and directly suppress its transcription. Together, these results suggest that NO-activated nucleocytoplasmic MdERF5 suppresses the action of ethylene biosynthetic genes, thereby suppressing ethylene biosynthesis and limiting fruit ripening.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/nph.18071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9313842PMC
June 2022

Exogenous gibberellin treatment improves fruit quality in self-pollinated apple.

Plant Physiol Biochem 2022 Mar 29;174:11-21. Epub 2022 Jan 29.

Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193, China. Electronic address:

Although a few apple (Malus × ×domestica) varieties are self-compatible, little is known about the differences in fruit quality between self- and cross-pollinated apple. In our current study, we compared the fruit quality of self-pollinated apple plants (cultivar 'Hanfu') in self-pollination or cross-pollinated by another cultivar 'Qinguan'. Analysis of fruit quality revealed substantial differences in the external qualities between self- and cross-pollinated apple fruit, but not in the internal qualities. Fruits harvested from self-pollinated 'Hanfu' were smaller and more asymmetrical than those harvested from the cross-pollinated plants. We developed a mathematical model describing how seed number and distribution affect fruit growth. According to this model, the fewer the seeds, the greater the force released from the seeds and the more asymmetrical the fruit. Detection of endogenous hormone and the associated gene expression revealed that gibberellin (GA) levels and GA transporter gene expression on the seedless side were significantly lower than those on the seeded side. Analysis of fruit pectin methylesterase activity and demethylated pectin levels indicated that the lack of GA limits fruit cell wall extension. Additionally, spraying the self-pollinating plants with gibberellic acid increased the fruit weight and lowered the proportion of asymmetrical fruit, recovering the exterior fruit quality to that of the cross-pollinated fruit. Furthermore, exogenous GA treatment increased the wax layer thickness and reduced the fruit water loss rate, leading to a dramatic improvement in fruit storage capacity. Therefore, exogenous GA treatment could be used to ensure regular fruit production of self-pollinated 'Hanfu'.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.plaphy.2022.01.029DOI Listing
March 2022

Polyamines Involved in Regulating Self-Incompatibility in Apple.

Genes (Basel) 2021 11 15;12(11). Epub 2021 Nov 15.

College of Horticulture, China Agricultural University, Beijing 100193, China.

Apple exhibits typical gametophytic self-incompatibility, in which self-S-RNase can arrest pollen tube growth, leading to failure of fertilization. To date, there have been few studies on how to resist the toxicity of self-S-RNase. In this study, pollen tube polyamines were found to respond to self-S-RNase and help pollen tubes defend against self-S-RNase. In particular, the contents of putrescine, spermidine, and spermine in the pollen tube treated with self-S-RNase were substantially lower than those treated with non-self-S-RNase. Further analysis of gene expression of key enzymes in the synthesis and degradation pathways of polyamines found that the expression of () as well as several polyamine oxidases such as (), (), and () were significantly up-regulated under self-S-RNase treatment, resulting in the reduction of polyamines. Silencing in pollen tubes alleviates the inhibitory effect of self-S-RNase on pollen tube growth. In addition, exogenous polyamines also enhance pollen tube resistance to self-S-RNase. Transcriptome sequencing data found that polyamines may communicate with S-RNase through the calcium signal pathway, thereby regulating the growth of the pollen tubes. To summarize, our results suggested that polyamines responded to the self-incompatibility reaction and could enhance pollen tube tolerance to S-RNase, thus providing a potential way to break self-incompatibility in apple.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/genes12111797DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8620888PMC
November 2021

Keystone taxa-mediated bacteriome response shapes the resilience of the paddy ecosystem to fungicide triadimefon contamination.

J Hazard Mater 2021 09 9;417:126061. Epub 2021 May 9.

Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China; Global Education Program for AgriScience Frontiers, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan. Electronic address:

The increasing input of fungicides has emerged as a global concern for agroecosystem stability and sustainability. Agroecosystem resilience has been linked to microbiome response, however, is not well understood. Focusing on a widespread triazole-class fungicide triadimefon in the paddy ecosystem, we characterized that the soils and sediments were dominant triadimefon reservoirs with the peak level at 195 μg kg and 31.3 μg kg, respectively, but essential for the resilience of paddy ecosystem to triadimefon. In paddy simulation models, the half-life of triadimefon in soil-sediment was 8.4-28.9 days, while it was prolonged to 86.6-115.5 days after elimination of resident microbial community. Phospholipid fatty acid profiling and high-throughput sequencing showed that the distinctive bacterial community responses contributed to variable degradation of triadimefon in paddy soils and sediments. Sphingomonas and Xanthomonas were identified as positive responders of the keystone taxa in the responsive bacteriome, whereas Enterobacter were negative responders that declined over time. Synthetic assemblages combined with quantitative polymerase chain reaction further validated that Sphingomonas and Xanthomonas were involved in sustaining soil-sediment resilience to triadimefon contamination. Collectively, our results revealed that the shaping of soil and sediment bacteriomes was responsible for the resilience of the paddy agroecosystem to fungicide contamination.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2021.126061DOI Listing
September 2021

Screening and functional verification of the target protein of pedunsaponin A in the killing of Pomacea canaliculata.

Ecotoxicol Environ Saf 2021 Sep 5;220:112393. Epub 2021 Jun 5.

College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China. Electronic address:

Previous study found that pedunsaponin A (PA) influenced the cytoskeleton of Pomacea canaliculata hemocytes, leading to depolarization and haemocyte destruction and eventually to snail death. In this study, we analysed the changes in protein expression by iTRAQ-mediated proteomics and identified 51 downregulated proteins. Among these, we focused on proteins related to cytoskeletal function and identified neural Wiskott-Aldrich syndrome isoform X1 (PcnWAS). The full-length PcnWAS gene contains 9791 bp and includes an open reading frame of 1401 bp that encodes 735 amino acids with a predicted molecular mass of 49.83 kD. PcnWAS exhibited a relatively distant genetic relationship with known species; the closest homologue is Biomphalaria glabrata (57%). RNA interference (RNAi) was adopted to verify the function of PcnWAS after screening the siRNA sequence with an efficiency of 97%. Interference with the gene expression of PcnWAS did not lead to snail death, but the depolarization level increased, which demonstrated that PcnWAS is an important depolarization-related protein. The results of PA treatment of snails subjected to RNAi proved that interfering with PcnWAS gene expression decreased the molluscicidal activity of PA toward P. canaliculata; snail mortality after RNAi was significantly lower (40%) than that in PA-treated snails without RNAi (54%), while the survival rate and depolarization level in haemocytes were not significant, indicating that PcnWAS is only one of the important target proteins of PA in P. canaliculata. This study lays the foundation for further exploration of the molecular mechanism by which PA kills this harmful snail.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ecoenv.2021.112393DOI Listing
September 2021

Mycoplasma ovipneumoniae-derived lipid-associated membrane proteins induce cytokine secretion in mouse peritoneal macrophages through TLR2 signalling.

Res Vet Sci 2020 Oct 31;132:474-480. Epub 2020 Jul 31.

Key Laboratory of Microbiology and Immunology, College of Veterinary Medicine, Inner Mongolia Agricultural University, No. 306 Zhaowuda Road, Saihan District, Hohhot 010018, China. Electronic address:

Background: Mycoplasma ovipneumoniae (M. ovi) is the causative agent of chronic non-progressive pneumonia in sheep, goats, bighorn, and wild small ruminants. However, the mechanism of infection and immune response to M. ovi remain unclear. Invading microbes express lipid-associated membrane proteins (LAMPs) on the cell surface that interact with host cells to facilitate infection, and are thus the major molecules recognised by the host immune system. Upon LAMP recognition, Toll-like receptor 2 (TLR2) and NLRP3 inflammasome sense the pathogens and signalling pathways for cytokine secretion. In this study, we investigated whether M. ovi and M. ovi-derived LAMPs are immuno-biologically active compounds capable of activating mouse peritoneal macrophages and explored the underlying mechanism.

Results: After infection of wild-type mice with M. ovi, the expression of TLR2 and NLRP3 at the transcriptional and translational levels was determined with reverse transcription-polymerase chain reaction and flow cytometry. In addition, the cytokine levels and associated pathways were detected in infected wild-type, Tlr2, and Nlrp3 mice via enzyme-linked immunosorbent assays and western blotting. The nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signalling pathways were found to mediate the expression of inflammatory cytokines in M. ovi or M. ovi-derived LAMP-infected peritoneal macrophages, and cytokines were not induced in Tlr2 and/or Nlrp3 macrophages.

Conclusion: Host cytokine production is activated in response to M. ovi-derived LAMPs through the NF-κB and MAPK signalling pathway via TLR2.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rvsc.2020.07.022DOI Listing
October 2020

Auxin-activated MdARF5 induces the expression of ethylene biosynthetic genes to initiate apple fruit ripening.

New Phytol 2020 06 28;226(6):1781-1795. Epub 2020 Mar 28.

College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China.

The gaseous plant hormone ethylene induces the ripening of climacteric fruit, including apple (Malus domestica). Another phytohormone, auxin, is known to promote ethylene production in many horticultural crops, but the regulatory mechanism remains unclear. Here, we found that auxin application induces ethylene production in apple fruit before the stage of commercial harvest, when they are not otherwise capable of ripening naturally. The expression of MdARF5, a member of the auxin response factor transcription factor (TF) family involved in the auxin signaling pathway, was enhanced by treatment with the synthetic auxin naphthaleneacetic acid (NAA). Further studies revealed that MdARF5 binds to the promoter of MdERF2, encoding a TF in the ethylene signaling pathway, as well as the promoters of two 1-aminocyclopropane-1-carboxylic acid synthase (ACS) genes (MdACS3a and MdACS1) and an ACC oxidase (ACO) gene, MdACO1, all of which encode key steps in ethylene biosynthesis, thereby inducing their expression. We also observed that auxin-induced ethylene production was dependent on the methylation of the MdACS3a promoter. Our findings reveal that auxin induces ethylene biosynthesis in apple fruit through activation of MdARF5 expression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/nph.16500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317826PMC
June 2020

iTRAQ-based proteomic analysis of Mycoplasma bovis NM-28 strain from two generations for vaccine screening.

Vaccine 2020 01 15;38(3):549-561. Epub 2019 Nov 15.

Key Laboratory of Microbiology & Immunology, College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010018, PR China. Electronic address:

Mycoplasma bovis is an important pathogenic bacterium affecting cows and cattle. Clinically, an inactivated vaccine of M. bovis is mainly used to prevent infection by this bacterium. The changes that occur in the antigen when M. bovis is continuously passaged in vitro remain unknown. Therefore, we performed an in vitro serial passage of the M. bovis NM-28 strain, which was isolated and identified in our laboratory. An isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics method was used to analyse the differences between generations 3 and 60. Many major membrane proteins or protective antigens reported in the literature did not exhibit changes between these generations. We found an imbalance between growth rate and nutrition in the 60th generation. The proteomics results were verified by western blotting and real-time PCR. Growth curves were also prepared based on colony-forming units (CFUs) between the 3rd and 60th generations. The number of colonies in the 60th generation in the stationary phase was 5 × 10 CFU mL, which was 10-fold higher than that in the 3rd generation. The 60th generation of the NM-28 strain can be used as an inactivated vaccine strain of M. bovis to lower production costs compared to use of the 3rd generation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.vaccine.2019.10.061DOI Listing
January 2020

Study of the Differentially Expressed Genes in the Transcriptome after Treatment with Pedunsaponin A.

Metabolites 2019 Nov 6;9(11). Epub 2019 Nov 6.

College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China.

Transcriptomes, genomes, and proteomes have played important roles in the search for drug targets. To determine the molluscicidal mechanism of pedunsaponin A against , RNA-seq technology was adopted to analyze the differentially expressed genes (DEGs) in the transcriptome after treatment with pedunsaponin A. As a result, 533 DEGs were identified, among which 255 genes were significantly upregulated and 278 genes were significantly downregulated. According to the analysis of Gene Ontology (GO) functions, we found that the DEGs were significantly enriched in the viral life cycle, UDP-glucose 4-epimerase activity, guanylate cyclase activity, the cyclic guanosine monophosphate (cGMP) biosynthetic process, and the cGMP metabolic process. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway results showed that the DEGs were mainly involved in the hedgehog signaling pathway, phagosome, cytosolic DNA-sensing pathway, retinoic acid-inducible gene I like (RIG-I-like) receptor signaling pathway, bacterial secretion system, and nuclear factor-kappa B (NF-kappa B) signaling pathway. The above results indicated that pedunsaponin A causes a metabolic disorder, anomalous opening of membrane ion channels, and an imbalance in osmotic pressure between the interior and exterior of cells, eventually resulting in the death of cells involved in immune defense and influencing the immune response of .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/metabo9110268DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6918322PMC
November 2019

The Damaging Effects of Pedunsaponin A on Hemocytes.

Toxins (Basel) 2019 07 4;11(7). Epub 2019 Jul 4.

College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China.

hemocytes are the main functional cells in the immune defense system, and hemocyte destruction disrupts the immune response mechanism of , resulting in abnormal growth, development, reproduction, and even death. Our previous study found that Pedunsaponin A significantly affects hemocyte structure. This study further investigated the damaging effects of Pedunsaponin A on hemocytes. The cell mortality rate results showed that the hemocyte mortality was significantly increased after treatment with Pedunsaponin A, and the mortality rate exhibited a significant positive correlation with treatment time and dose. The membrane potential results showed that the cell membranes of hemocytes exhibited time-dependent membrane depolarization after 40 mg/L Pedunsaponin A treatment. At 36 h, the cell depolarization rate in the Pedunsaponin A treatment group was 41.43%, which was significantly greater than the control group (6.24%). The cytoskeleton results showed that Pedunsaponin A led to disordered and dispersed arrangement of microfilaments and changes in the cytoskeletal structure. The apoptosis and cell cycle results showed that Pedunsaponin A induced apoptosis and influenced the cell cycle to some extent. These results showed that the cell membrane and cytoskeleton of hemocytes were damaged after treatment with Pedunsaponin A, which led to an increase in cell mortality, dysfunction, cell cycle abnormalities and apoptosis. This study provides a foundation for further identification of the site of Pedunsaponin A activity on hemocytes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/toxins11070390DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669518PMC
July 2019

Compounds from the root of Pueraria peduncularis (Grah. ex Benth.) Benth. and their antimicrobial effects.

Pest Manag Sci 2019 Oct 27;75(10):2765-2769. Epub 2019 Mar 27.

Department of Plant Protection, College of Agronomy, Sichuan Agricultural University, Chengdu, China.

Background: Pueraria peduncularis belongs to the genus Pueraria DC, and has a wide range of medical and agricultural activities. Previous studies have shown that P. peduncularis extracts have broad bioactivities against phytopathogens. In this paper, we systematically studied the fungicidal activity of root methanol extracts and further isolated the active compounds.

Results: The root methanol extract inhibited the mycelial growth of the five tested phytopathogens to different degrees. Among these phytopathogens, the inhibitory effect was greatest against R. solani, with an EC value of 324.72 mg L . Eight compounds were subsequently isolated and identified from P. peduncularis. Among them, puercarpan A and medicarpin showed strong fungicidal activity, with MIC values against Rhizoctonia solani of 1.6 and 6.25 mg L , respectively. Puercarpan A is a new compound, and its structure was established as (6aR,6bS,11aR)-6b-hydroxy-3-methoxypterocarpan-10-ene-7-one.

Conclusion: The P. peduncularis extracts exhibit high antimicrobial activity against R. solani and have great potential value of P. peduncularis as a fungicide. © 2019 Society of Chemical Industry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ps.5387DOI Listing
October 2019

Histopathological effects of Pedunsaponin A on Pomacea canaliculata.

Pestic Biochem Physiol 2018 Jun 25;148:151-158. Epub 2018 Apr 25.

College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China. Electronic address:

Pedunsaponin A, a novel molluscicidal compound isolated from Pueraria peduncularis, exhibits strong toxicity against Pomacea canaliculata. To determine the mechanisms of Pedunsaponin A toxicity, its effects on the organs and hemocytes of P. canaliculata were examined in this study. The results showed that Pedunsaponin A had significant toxic effects on different organs of the snail, including the lungs, gills, mantle, siphon tube, ventricle, pericardial cavity, hepatopancreas, kidneys, and the major symptom of this toxicity was the loss of cilia in the lungs and gills. Additionally, in further studies on the effects of Pedunsaponin A treatment, we found that the hemocyte count was changed and hemocyte morphology was damaged, which was primarily reflected by cytoplasm leakage, nuclei deformation, and significant reductions in the number of ribosomes and granulocyte mitochondria. Based on these results and considering that blood vessels are distributed in the lungs and gills, we hypothesized that Pedunsaponin A would first destroy the cilia, which disrupt physiological activities such as respiration, excretion and feeding, and then enter the hemolymph through blood vessels, disrupt the normal function of the hemocytes and destroy the snail immune system, eventually resulting in the death of the snail.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.pestbp.2018.04.010DOI Listing
June 2018
-->