Pseudomonas syringae pv.actinidiae(Psa)causes destructive kiwifruit bacterial canker by invading vascular tissues across multiple plant organs.However,the cellular mechanism underlying its systemic transmission and ce...Pseudomonas syringae pv.actinidiae(Psa)causes destructive kiwifruit bacterial canker by invading vascular tissues across multiple plant organs.However,the cellular mechanism underlying its systemic transmission and cell-to-cell movement within these specialized vascular conduits remains unclear.In this study,a Psa-GFP strain and various microscopic techniques were used to investigate the interaction between kiwifruit and Psa.Our results reveal that Psa strategically exploits host vascular conduits for systemic movement,with the xylem vessel being the predominant avenue.In the phloem,Psa exhibits adaptive alteration in bacterial shape to traverse sieve pores,facilitating its systemic spread along sieve tubes and inducing phloem necrosis.Within the xylem,Psa breaches pit membranes to migrate between adjacent vessels.Furthermore,phloem fibers act as an initial barrier at the early stages of infection,delaying Psa's entry into vascular tissues during its journey to the xylem.Additionally,at the junctions of stem-stem or stem-leaf,branch trace or leaf trace mediates the bacterial organ-to-organ translocation,thus facilitating the systemic progression of disease.In conclusion,our findings shed light on the cellular mechanism employed by Psa to exploit the woody plant's vascular network for infection,thereby enhancing a better understanding of the biology of this poorly defined bacterium.These insights carry implications for the pathogenesis of Psa and other vascular pathogens,offering theoretical guidance for effective control strategies.展开更多
Pseudomonas syringae pv.actinidiae(Psa)causes bacterial canker,a devastating disease threatening the Actinidia fruit industry.In a search for non-host resistance genes against Psa,we find that the nucleotidebinding le...Pseudomonas syringae pv.actinidiae(Psa)causes bacterial canker,a devastating disease threatening the Actinidia fruit industry.In a search for non-host resistance genes against Psa,we find that the nucleotidebinding leucine-rich repeat receptor(NLR)protein ZAR1 from both Arabidopsis and Nicotiana benthamiana(Nb)recognizes Hop Z5 and triggers cell death.The recognition requires ZED1 in Arabidopsis and JIM2 in Nb plants,which are members of the ZRK pseudokinases and known components of the ZAR1 resistosome.Surprisingly,Arabidopsis ZAR1 and RPM1,another NLR known to recognize Hop Z5,confer disease resistance to Hop Z5 in a strain-specific manner.Thus,ZAR1,but not RPM1,is solely required for resistance to P.s.maculicola ES4326(Psm)carrying hop Z5,whereas RPM1 is primarily required for resistance to P.s.tomato DC3000(Pst)carrying hop Z5.Furthermore,the ZAR1-mediated resistance to Psm hop Z5 in Arabidopsis is insensitive to SOBER1,which encodes a deacetylase known to suppress the RPM1-mediated resistance to Pst hop Z5.In addition,hop Z5 enhances P.syringae virulence in the absence of ZAR1 or RPM1 and that SOBER1 abolishes such virulence function.Together the study suggests that ZAR1 may be used for improving Psa resistance in Actinidia and uncovers previously unknown complexity of effectortriggered immunity and effector-triggered virulence.展开更多
Objective Radix of Actinidiae chinensis,a medicinal plant used in China,is the dry root of Actini-diaceae plant and has been extensively employed to treat cancers of various organs,including the lung,liver and digesti...Objective Radix of Actinidiae chinensis,a medicinal plant used in China,is the dry root of Actini-diaceae plant and has been extensively employed to treat cancers of various organs,including the lung,liver and digestive system.However,up to now,its active antitumor and antiviral fractions remain unclear.The main purpose of this study is to identify the antitumor and antiviral sites of Radix of Actinidiae chinensis,which provides evidences for its further development.Methods Radix of Actinidiae chinensis was extracted by the refluxing sequentially with acetidin,ethanol and water,followed by the column chromatography and thin layer chromatography.The antitumor effects on Bel-7402,SW-620 and MDA-MB-231 tumor cells were investigated to screen the active antitumor sites by cell inhibition,the growth curve and the apoptosis staining.Meanwhile,to screen the active anti-hepatovirus fractions,the cell growth and the secretion of HBsAg and HBeAg in HepG2.2.15 cells were evaluated by the MTT test and enzyme-linked immunosorbent assay respectively.Results The acetidin fraction Y(Y1+Y2),the ethanol fraction A(A1+A3+A4) and B(A1+A4+A6),and the fraction compound C(A1+A4+Y1) have strong inhibitive effects on Bel-7402,SW-620 and MDA-MB-231 tumor cell lines.Moreover,the tumor cell apoptosis could be induced by the ethanol fraction B and the fraction compound C.In HepG2.2.15 cells,the treatment indexes of the acetidin fraction Y,the ethanol fraction A and the fraction compound C all exceeded 2 on the secretion of HBsAg,indicating the suppre-ssive effects of them on hepatitis B virus.The fraction yields of A,B and C exceeded 50%(60.28%,54.35% and 62.64% respectively),while that of Y did not(17.7%).Conclusion The ethanol fraction B and the fraction compound C are the antitumor sites of Actinidiae chinensis Radix,while the ethanol fraction A and the fraction compound C are its antiviral sites.展开更多
The genus Actinidia is primarily functionally dioecious,and early sex identification plays a crucial role in improving breeding efficiency and reducing production costs.In this study,the accuracy of three sex-linked m...The genus Actinidia is primarily functionally dioecious,and early sex identification plays a crucial role in improving breeding efficiency and reducing production costs.In this study,the accuracy of three sex-linked molecular markers(SyGI[Shy Girl],FrBy[Friendly Boy],and SmY1)in sex identification was evaluated in various Actinidia species.The selected marker products were subsequently cloned and sequenced in six wild Actinidia species.Ninety-six wild A.chinensis chinensis accessions and 74 A.chinensis deliciosa accessions,most of which were wild,with only one cultivated,were used for comprehensive primer validation.Thirty-three juvenile A.chinensis chinensis hybrid seedlings were used for practical application tests.The results showed that the marker SyGI accurately identified the sex of 20 samples from six Actinidia species and 96 A.chinensis chinensis accessions with 100%reliability.For Actinidia chinensis deliciosa,the identification accuracy reached 98.65%.Sequence analysis revealed that SyGI shared the highest similarity with the male-specific genomic region.Furthermore,SyGI achieved 100%accuracy in identifying the sex of 33 juvenile A.chinensis chinensis individuals.The findings confirm that the SyGI marker possesses high accuracy,strong specificity,and broad applicability,making it a valuable tool for kiwifruit breeding programs.The cloned sequences from wild Actinidia species also provide important references for future research on the mechanisms of sexual evolution and determination.展开更多
The extracytoplasmic function(ECF)sigma factor AlgU is involved in the regulation of various virulence-related pathways in Pseudomonas syringae,especially alginate biosynthesis and motility,and the role of AlgU differ...The extracytoplasmic function(ECF)sigma factor AlgU is involved in the regulation of various virulence-related pathways in Pseudomonas syringae,especially alginate biosynthesis and motility,and the role of AlgU differs among P.syringae pathovars.However,to date,the mechanism of its regulation in virulence of P.syringae pv.actinidiae(Psa)is still unclear.ECF sigma factors are a class of alternative sigma factors that typically function with anti-sigma factors as part of cell-surface signaling systems.Under non-inducing conditions,AlgU remains inhibited by anti-sigma factors such as MucA and MucB.To investigate the function of AlgU in Psa,mutant strains lacking algU or lacking algU with mucA and mucB genes,as well as complementary and overexpression strains of algU were generated,respectively.The results showed that AlgU was highly conserved among P.syringae pathovars and positively regulated growth rate,pathogenicity,and resistance to osmotic and oxidative stress of Psa QSY6.While AlgU did not affect the motility and exopolysaccharide production of Psa,its abundant expression enhanced the swimming ability of QSY6 and reduced its production of extracellular polysaccharides.Furthermore,AlgU regulates a number of virulence-related factors,including the Hrp system,the type VI secretion system,and flagellar synthesis.Specifically,AlgU induced the expression of hrpL and hrpRS in vivo,and repressed the transcription of hrpL and tssC in vitro,while promoting the expression of hrpS,fliC,and tssJ.This study contributes to a better understanding of the mechanisms of virulence regulation of AlgU in Psa.展开更多
Ambient temperature affects the occurrence and prevalence of plant disease.Most bacterial diseases are damaging at high temperatures.However,kiwifruit bacterial canker caused by Pseudomonas syringae pv.actinidiae(Psa)...Ambient temperature affects the occurrence and prevalence of plant disease.Most bacterial diseases are damaging at high temperatures.However,kiwifruit bacterial canker caused by Pseudomonas syringae pv.actinidiae(Psa)has been found to be prevalent at relatively cool temperatures,and it is unclear how ambient temperature affects the development of kiwifruit bacterial canker.In this study,basal resistance to Psa was suppressed in kiwifruit at cool growth temperature(16℃)compared with at normal temperature(24℃).In addition,RNA sequence analysis and ethylene content assessment indicated that ethylene modulated kiwifruit resistance to Psa at normal growth temperature and that cool temperature inhibited ethylene accumulation and Psa-induced activation of the ethylene signaling pathway in kiwifruit.Virusmediated silencing of the kiwifruit ethylene signaling gene AcEIN2 suppressed kiwifruit resistance to Psa at normal growth temperature.Exogenous application of ethylene inhibitor 1-methylcyclopropene eliminated the difference in kiwifruit resistance to Psa at 16 and 24℃.Exogenous application of ethylene analogues ethephon induced resistance to Psa in kiwifruit.In conclusion,cool temperatures impair basal resistance to Psa by reducing the activation of ethylene biosynthesis and signaling in kiwifruit.The results provide clues for new strategies to control plant diseases in a context of global environmental change.展开更多
Waterlogging stress is one of the greatest environmental threats to kiwifruit growth and development.ERF-VII proteins have been demonstrated to play pivotal roles in regulating plant tolerance to waterlogging.Neverthe...Waterlogging stress is one of the greatest environmental threats to kiwifruit growth and development.ERF-VII proteins have been demonstrated to play pivotal roles in regulating plant tolerance to waterlogging.Nevertheless,the genome-wide role of ERF-VII in kiwifruit waterlogging stress tolerance remains unclear.Here,we report the function and regulatory network of an ERF-VII transcription factor located to the nucleus,Av ERF73,in kiwifruit waterlogging tolerance.Overexpression of Av ERF73 in Arabidopsis thaliana and A.chinensis cv.Hongyang enhanced waterlogging tolerance in transgenic plants.Furthermore,we performed transcriptome analysis(RNA-seq)and DNA affinity purification sequencing(DAP-seq)to explore the regulatory mechanism of Av ERF73.RNA-seq coupled with DAP-seq showed that Av ERF73 might directly activate Ac NAC022 involved in the“cellular response to hypoxia”process and Ac HMGS1 involved in the mevalonate pathway to respond to waterlogging,which were also confirmed by a dual-luciferase reporter assay.Based on our results,we propose a putative working model for controlling waterlogging tolerance by Av ERF73 in kiwifruit.展开更多
Bacterial canker disease caused by Pseudomonas syringae pv.actinidiae(Psa)is the most devastating disease in kiwifruit cultivation.The EnvZ/OmpR two-component system(TCS)has been confirmed to regulate virulence and me...Bacterial canker disease caused by Pseudomonas syringae pv.actinidiae(Psa)is the most devastating disease in kiwifruit cultivation.The EnvZ/OmpR two-component system(TCS)has been confirmed to regulate virulence and mediate environmental stress responses in Gram-negative bacteria.However,the functional role of EnvZ/OmpR in Psa has not been fully clarified.In this study,we constructed markerless ompR,envZ,and ompR-envZ mutants,and ompR complementation and overexpression strains using homologous recombination.The deletion of ompR or envZ tremendously reduced the swimming and swarming motility of Psa,as well as tolerance to osmotic stress,while overexpression of ompR impaired its virulence against kiwifruit but enhanced exopolysaccharide production.EnvZ negatively regulated hrpR/S expression in both King’s B and minimal medium,whereas OmpR regulated hrpR/S expression negatively in King’s B and positively in minimal medium.However,OmpR did not regulate the expression of genes gacA,algU,lpxC,fur,and fleQ,which are associated with known virulence functions,despite its binding to their promoters.Additionally,based on bioinformatic prediction,two new OmpR regulons(envC and tolQ)related to virulence were identified in Psa.Meanwhile,OmpR directly bound to the promoters of envC and tolQ,and negatively regulated their expression in minimal medium.These findings enrich our understanding of the OmpR-mediated regulatory network and its roles in the pathogenesis of P.syringae.展开更多
Kiwifruit bacterial canker is a devastating disease caused by Pseudomonas syringae pv.actinidiae(Psa).NAC transcription factors play a significant role in host immunity.However,the potential molecular mechanism of res...Kiwifruit bacterial canker is a devastating disease caused by Pseudomonas syringae pv.actinidiae(Psa).NAC transcription factors play a significant role in host immunity.However,the potential molecular mechanism of resistance to semi-biotrophic Psa mediated by NAC transcription factors in kiwifruit remains unclear.In this study,we identified a typical NAC transcription factor,AcNAC10,which is involved in the jasmonic acid(JA)pathway and is highly expressed in resistant variety RH12 responsing to Psa.By overexpression and silencing of AcNAC10 in kiwifruit,it plays a positive role in enhancing kiwifruit resistance.Likewise,heterologous expression of AcNAC10 in transgenic Arabidopsis and tomato enhanced resistance to P.syringae.By directly binding to the promoter of AcLOX3,AcNAC10 inhibited its expression as a transcriptional suppressor.Using a yeast one-hybrid screening library,electrophoretic mobility shift assay(EMSA),and dual-luciferase reporter assays,it showed that AcTGA07 can activate the expression of AcNAC10.Moreover,we demonstrated that AcTGA07 decreased JA accumulation independently of the AcNAC10-AcLOX3 pathway.Our study elucidated the transcriptional cascade regulatory network of AcTGA07-AcNAC10-AcLOX3,which enhanced the disease resistance of kiwifruit to Psa by inhibiting JA synthesis.展开更多
Kiwifruit bacterial canker(KBC),caused by Pseudomonas syringae pv.actinidiae(Psa),poses a severe threat to the global kiwifruit industry,highlighting the urgent need to elucidate its pathogenic mechanisms.Cyclic digua...Kiwifruit bacterial canker(KBC),caused by Pseudomonas syringae pv.actinidiae(Psa),poses a severe threat to the global kiwifruit industry,highlighting the urgent need to elucidate its pathogenic mechanisms.Cyclic diguanylate monophosphate(c-di-GMP)is a bacterial second messenger synthesized by GGDEF domain-containing diguanylate cyclases and degraded by EAL or HD-GYP domain-containing phosphodiesterases.In this study,we characterized PSA_2989,a protein containing both GGDEF and EAL domains,hereafter referred to as DcvP(Diguanylate cyclase regulating virulence in Psa).Biochemical assays demonstrated that DcvP exhibits both DGC and PDE activities in vitro,with DGC activity being more prominent in vivo.Deletion of dcvP enhanced the virulence of Psa on kiwifruit leaves.Transcriptomic and RT-qPCR analyses revealed that DcvP suppresses the expression of type III secretion system(T3SS)genes,flagellar biosynthesis genes,and catalase genes,thereby reducing virulence,motility,and oxidative stress tolerance,primarily through its GGDEF domain.Furthermore,under microaerobic conditions,the expression of dcvP was significantly upregulated,accompanied by increased intracellular c-di-GMP levels and repression of T3SS genes.These results identify DcvP as a negative regulator of Psa virulence through DGC activity and also as being involved in the environmental oxygen response.This work provides new insights into the pathogenic mechanisms of Psa and highlights DcvP as a potential target for KBC control.展开更多
基金supported by grants from the National Key Research and Development Program of China(Grant No.2022YFD1400200)the Special Support Plan for High-Level Talent of Shaanxi Provincethe First-Class Universities and Academic Programs of Northwest A&F University.
文摘Pseudomonas syringae pv.actinidiae(Psa)causes destructive kiwifruit bacterial canker by invading vascular tissues across multiple plant organs.However,the cellular mechanism underlying its systemic transmission and cell-to-cell movement within these specialized vascular conduits remains unclear.In this study,a Psa-GFP strain and various microscopic techniques were used to investigate the interaction between kiwifruit and Psa.Our results reveal that Psa strategically exploits host vascular conduits for systemic movement,with the xylem vessel being the predominant avenue.In the phloem,Psa exhibits adaptive alteration in bacterial shape to traverse sieve pores,facilitating its systemic spread along sieve tubes and inducing phloem necrosis.Within the xylem,Psa breaches pit membranes to migrate between adjacent vessels.Furthermore,phloem fibers act as an initial barrier at the early stages of infection,delaying Psa's entry into vascular tissues during its journey to the xylem.Additionally,at the junctions of stem-stem or stem-leaf,branch trace or leaf trace mediates the bacterial organ-to-organ translocation,thus facilitating the systemic progression of disease.In conclusion,our findings shed light on the cellular mechanism employed by Psa to exploit the woody plant's vascular network for infection,thereby enhancing a better understanding of the biology of this poorly defined bacterium.These insights carry implications for the pathogenesis of Psa and other vascular pathogens,offering theoretical guidance for effective control strategies.
基金supported by grants from the National Key R&D Program of China (2021YFA1300701) to J.M.Z.the National Natural Science Foundation of China (31872654) to Z.Y.Z.the Hainan Excellent Talent Team, and the State Key Laboratory of Plant Genomics (SKLPG2016B-2) to J.M.Z
文摘Pseudomonas syringae pv.actinidiae(Psa)causes bacterial canker,a devastating disease threatening the Actinidia fruit industry.In a search for non-host resistance genes against Psa,we find that the nucleotidebinding leucine-rich repeat receptor(NLR)protein ZAR1 from both Arabidopsis and Nicotiana benthamiana(Nb)recognizes Hop Z5 and triggers cell death.The recognition requires ZED1 in Arabidopsis and JIM2 in Nb plants,which are members of the ZRK pseudokinases and known components of the ZAR1 resistosome.Surprisingly,Arabidopsis ZAR1 and RPM1,another NLR known to recognize Hop Z5,confer disease resistance to Hop Z5 in a strain-specific manner.Thus,ZAR1,but not RPM1,is solely required for resistance to P.s.maculicola ES4326(Psm)carrying hop Z5,whereas RPM1 is primarily required for resistance to P.s.tomato DC3000(Pst)carrying hop Z5.Furthermore,the ZAR1-mediated resistance to Psm hop Z5 in Arabidopsis is insensitive to SOBER1,which encodes a deacetylase known to suppress the RPM1-mediated resistance to Pst hop Z5.In addition,hop Z5 enhances P.syringae virulence in the absence of ZAR1 or RPM1 and that SOBER1 abolishes such virulence function.Together the study suggests that ZAR1 may be used for improving Psa resistance in Actinidia and uncovers previously unknown complexity of effectortriggered immunity and effector-triggered virulence.
基金Important National Science & Technology Specific Project (2009Z10603)Hunan Science andTechnology Project (2009FJ3209)
文摘Objective Radix of Actinidiae chinensis,a medicinal plant used in China,is the dry root of Actini-diaceae plant and has been extensively employed to treat cancers of various organs,including the lung,liver and digestive system.However,up to now,its active antitumor and antiviral fractions remain unclear.The main purpose of this study is to identify the antitumor and antiviral sites of Radix of Actinidiae chinensis,which provides evidences for its further development.Methods Radix of Actinidiae chinensis was extracted by the refluxing sequentially with acetidin,ethanol and water,followed by the column chromatography and thin layer chromatography.The antitumor effects on Bel-7402,SW-620 and MDA-MB-231 tumor cells were investigated to screen the active antitumor sites by cell inhibition,the growth curve and the apoptosis staining.Meanwhile,to screen the active anti-hepatovirus fractions,the cell growth and the secretion of HBsAg and HBeAg in HepG2.2.15 cells were evaluated by the MTT test and enzyme-linked immunosorbent assay respectively.Results The acetidin fraction Y(Y1+Y2),the ethanol fraction A(A1+A3+A4) and B(A1+A4+A6),and the fraction compound C(A1+A4+Y1) have strong inhibitive effects on Bel-7402,SW-620 and MDA-MB-231 tumor cell lines.Moreover,the tumor cell apoptosis could be induced by the ethanol fraction B and the fraction compound C.In HepG2.2.15 cells,the treatment indexes of the acetidin fraction Y,the ethanol fraction A and the fraction compound C all exceeded 2 on the secretion of HBsAg,indicating the suppre-ssive effects of them on hepatitis B virus.The fraction yields of A,B and C exceeded 50%(60.28%,54.35% and 62.64% respectively),while that of Y did not(17.7%).Conclusion The ethanol fraction B and the fraction compound C are the antitumor sites of Actinidiae chinensis Radix,while the ethanol fraction A and the fraction compound C are its antiviral sites.
基金funded by Sichuan Science and Technology Program,grant numbers 2021YFYZ0010,2023YFH0006,2025YFHZ0295The Basic Research Program of Sichuan Provincial Research Institutes,grant numbers 2024JDKY0001 and 2023JDKY0001.
文摘The genus Actinidia is primarily functionally dioecious,and early sex identification plays a crucial role in improving breeding efficiency and reducing production costs.In this study,the accuracy of three sex-linked molecular markers(SyGI[Shy Girl],FrBy[Friendly Boy],and SmY1)in sex identification was evaluated in various Actinidia species.The selected marker products were subsequently cloned and sequenced in six wild Actinidia species.Ninety-six wild A.chinensis chinensis accessions and 74 A.chinensis deliciosa accessions,most of which were wild,with only one cultivated,were used for comprehensive primer validation.Thirty-three juvenile A.chinensis chinensis hybrid seedlings were used for practical application tests.The results showed that the marker SyGI accurately identified the sex of 20 samples from six Actinidia species and 96 A.chinensis chinensis accessions with 100%reliability.For Actinidia chinensis deliciosa,the identification accuracy reached 98.65%.Sequence analysis revealed that SyGI shared the highest similarity with the male-specific genomic region.Furthermore,SyGI achieved 100%accuracy in identifying the sex of 33 juvenile A.chinensis chinensis individuals.The findings confirm that the SyGI marker possesses high accuracy,strong specificity,and broad applicability,making it a valuable tool for kiwifruit breeding programs.The cloned sequences from wild Actinidia species also provide important references for future research on the mechanisms of sexual evolution and determination.
基金supported by the National Natural Science Foundation of China(32072378)the Development Fund for Talent Personnel of Anhui Agricultural University(rc342216)the Undergraduate Innovation and Entrepreneurship Training Program of Anhui Agricultural University(X202310364527).
文摘The extracytoplasmic function(ECF)sigma factor AlgU is involved in the regulation of various virulence-related pathways in Pseudomonas syringae,especially alginate biosynthesis and motility,and the role of AlgU differs among P.syringae pathovars.However,to date,the mechanism of its regulation in virulence of P.syringae pv.actinidiae(Psa)is still unclear.ECF sigma factors are a class of alternative sigma factors that typically function with anti-sigma factors as part of cell-surface signaling systems.Under non-inducing conditions,AlgU remains inhibited by anti-sigma factors such as MucA and MucB.To investigate the function of AlgU in Psa,mutant strains lacking algU or lacking algU with mucA and mucB genes,as well as complementary and overexpression strains of algU were generated,respectively.The results showed that AlgU was highly conserved among P.syringae pathovars and positively regulated growth rate,pathogenicity,and resistance to osmotic and oxidative stress of Psa QSY6.While AlgU did not affect the motility and exopolysaccharide production of Psa,its abundant expression enhanced the swimming ability of QSY6 and reduced its production of extracellular polysaccharides.Furthermore,AlgU regulates a number of virulence-related factors,including the Hrp system,the type VI secretion system,and flagellar synthesis.Specifically,AlgU induced the expression of hrpL and hrpRS in vivo,and repressed the transcription of hrpL and tssC in vitro,while promoting the expression of hrpS,fliC,and tssJ.This study contributes to a better understanding of the mechanisms of virulence regulation of AlgU in Psa.
基金supported by grants from the National Key Research and Development Program of China(Grant No.2022YFD1400200)the Special Support Plan for High-Level Talent of Shaanxi Province。
文摘Ambient temperature affects the occurrence and prevalence of plant disease.Most bacterial diseases are damaging at high temperatures.However,kiwifruit bacterial canker caused by Pseudomonas syringae pv.actinidiae(Psa)has been found to be prevalent at relatively cool temperatures,and it is unclear how ambient temperature affects the development of kiwifruit bacterial canker.In this study,basal resistance to Psa was suppressed in kiwifruit at cool growth temperature(16℃)compared with at normal temperature(24℃).In addition,RNA sequence analysis and ethylene content assessment indicated that ethylene modulated kiwifruit resistance to Psa at normal growth temperature and that cool temperature inhibited ethylene accumulation and Psa-induced activation of the ethylene signaling pathway in kiwifruit.Virusmediated silencing of the kiwifruit ethylene signaling gene AcEIN2 suppressed kiwifruit resistance to Psa at normal growth temperature.Exogenous application of ethylene inhibitor 1-methylcyclopropene eliminated the difference in kiwifruit resistance to Psa at 16 and 24℃.Exogenous application of ethylene analogues ethephon induced resistance to Psa in kiwifruit.In conclusion,cool temperatures impair basal resistance to Psa by reducing the activation of ethylene biosynthesis and signaling in kiwifruit.The results provide clues for new strategies to control plant diseases in a context of global environmental change.
基金funded by the National Key Research and Development Program(Grant No.2022YFD1600700)Major Science and Technology Projects of Henan Province(Grant No.221100110400)+3 种基金the China Agriculture Research System of MOF and MARA(Grant No.CARS-26)Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Science(Grant No.CAAS-ASTIP-2023-ZFRI-03)Yunnan Science and Technology Program(Grant No.202205AF150043)Sichuan Science and Technology Program(Grant No.2021YFN0060)。
文摘Waterlogging stress is one of the greatest environmental threats to kiwifruit growth and development.ERF-VII proteins have been demonstrated to play pivotal roles in regulating plant tolerance to waterlogging.Nevertheless,the genome-wide role of ERF-VII in kiwifruit waterlogging stress tolerance remains unclear.Here,we report the function and regulatory network of an ERF-VII transcription factor located to the nucleus,Av ERF73,in kiwifruit waterlogging tolerance.Overexpression of Av ERF73 in Arabidopsis thaliana and A.chinensis cv.Hongyang enhanced waterlogging tolerance in transgenic plants.Furthermore,we performed transcriptome analysis(RNA-seq)and DNA affinity purification sequencing(DAP-seq)to explore the regulatory mechanism of Av ERF73.RNA-seq coupled with DAP-seq showed that Av ERF73 might directly activate Ac NAC022 involved in the“cellular response to hypoxia”process and Ac HMGS1 involved in the mevalonate pathway to respond to waterlogging,which were also confirmed by a dual-luciferase reporter assay.Based on our results,we propose a putative working model for controlling waterlogging tolerance by Av ERF73 in kiwifruit.
基金supported by the National Key R&D Program of China(2022YFD1400200)the National Natural Science Foundation of China(32072378)+1 种基金the Undergraduate Innovation and Entrepreneurship Training Program of Anhui Agricultural University(S202310364173)the Development Fund for Talent Personnel of Anhui Agricultural University(rc342216).
文摘Bacterial canker disease caused by Pseudomonas syringae pv.actinidiae(Psa)is the most devastating disease in kiwifruit cultivation.The EnvZ/OmpR two-component system(TCS)has been confirmed to regulate virulence and mediate environmental stress responses in Gram-negative bacteria.However,the functional role of EnvZ/OmpR in Psa has not been fully clarified.In this study,we constructed markerless ompR,envZ,and ompR-envZ mutants,and ompR complementation and overexpression strains using homologous recombination.The deletion of ompR or envZ tremendously reduced the swimming and swarming motility of Psa,as well as tolerance to osmotic stress,while overexpression of ompR impaired its virulence against kiwifruit but enhanced exopolysaccharide production.EnvZ negatively regulated hrpR/S expression in both King’s B and minimal medium,whereas OmpR regulated hrpR/S expression negatively in King’s B and positively in minimal medium.However,OmpR did not regulate the expression of genes gacA,algU,lpxC,fur,and fleQ,which are associated with known virulence functions,despite its binding to their promoters.Additionally,based on bioinformatic prediction,two new OmpR regulons(envC and tolQ)related to virulence were identified in Psa.Meanwhile,OmpR directly bound to the promoters of envC and tolQ,and negatively regulated their expression in minimal medium.These findings enrich our understanding of the OmpR-mediated regulatory network and its roles in the pathogenesis of P.syringae.
基金financially supported by the National Key R&D Program of China(2022YFD1400200)the Natural Science Foundation of China grant 32102174 awarded to W.L.
文摘Kiwifruit bacterial canker is a devastating disease caused by Pseudomonas syringae pv.actinidiae(Psa).NAC transcription factors play a significant role in host immunity.However,the potential molecular mechanism of resistance to semi-biotrophic Psa mediated by NAC transcription factors in kiwifruit remains unclear.In this study,we identified a typical NAC transcription factor,AcNAC10,which is involved in the jasmonic acid(JA)pathway and is highly expressed in resistant variety RH12 responsing to Psa.By overexpression and silencing of AcNAC10 in kiwifruit,it plays a positive role in enhancing kiwifruit resistance.Likewise,heterologous expression of AcNAC10 in transgenic Arabidopsis and tomato enhanced resistance to P.syringae.By directly binding to the promoter of AcLOX3,AcNAC10 inhibited its expression as a transcriptional suppressor.Using a yeast one-hybrid screening library,electrophoretic mobility shift assay(EMSA),and dual-luciferase reporter assays,it showed that AcTGA07 can activate the expression of AcNAC10.Moreover,we demonstrated that AcTGA07 decreased JA accumulation independently of the AcNAC10-AcLOX3 pathway.Our study elucidated the transcriptional cascade regulatory network of AcTGA07-AcNAC10-AcLOX3,which enhanced the disease resistance of kiwifruit to Psa by inhibiting JA synthesis.
基金supported by the Natural Key Research and Development Program(2022YFD1400200 to Yao Wang and Mingming Yang)National Natural Science Foundation of China(32330004 to Xihui Shen,32170130 to Wang Yao and 32102283 to Mingming Yang).
文摘Kiwifruit bacterial canker(KBC),caused by Pseudomonas syringae pv.actinidiae(Psa),poses a severe threat to the global kiwifruit industry,highlighting the urgent need to elucidate its pathogenic mechanisms.Cyclic diguanylate monophosphate(c-di-GMP)is a bacterial second messenger synthesized by GGDEF domain-containing diguanylate cyclases and degraded by EAL or HD-GYP domain-containing phosphodiesterases.In this study,we characterized PSA_2989,a protein containing both GGDEF and EAL domains,hereafter referred to as DcvP(Diguanylate cyclase regulating virulence in Psa).Biochemical assays demonstrated that DcvP exhibits both DGC and PDE activities in vitro,with DGC activity being more prominent in vivo.Deletion of dcvP enhanced the virulence of Psa on kiwifruit leaves.Transcriptomic and RT-qPCR analyses revealed that DcvP suppresses the expression of type III secretion system(T3SS)genes,flagellar biosynthesis genes,and catalase genes,thereby reducing virulence,motility,and oxidative stress tolerance,primarily through its GGDEF domain.Furthermore,under microaerobic conditions,the expression of dcvP was significantly upregulated,accompanied by increased intracellular c-di-GMP levels and repression of T3SS genes.These results identify DcvP as a negative regulator of Psa virulence through DGC activity and also as being involved in the environmental oxygen response.This work provides new insights into the pathogenic mechanisms of Psa and highlights DcvP as a potential target for KBC control.
