The pear is an economic fruit that is widely planted around the world and is loved by people for its rich nutritional value. Autophagy is a self-protection mechanism in eukaryotes, and its occurrence often accompanied...The pear is an economic fruit that is widely planted around the world and is loved by people for its rich nutritional value. Autophagy is a self-protection mechanism in eukaryotes, and its occurrence often accompanied by the degradation of damaged substances in cells and the recycling of nutrients. Autophagy is one of the mechanisms through which plants respond to environmental stress and plays an important role in plant development and stress resistance. Functional studies of autophagy-related genes (ATGs) have been performed on a variety of plant species, but little information is available on the ATG family in pear (Pyrus bretschneideri Rehd). Therefore, we analyzed the evolutionary dynamics and performed a genome-wide characterization of the PbrATG gene family. A total of 28 PbrATG members were identified.Phylogenetic analysis showed that PbrATGs were more closely related to ATGs of European pear and apple. Evolutionary analysis revealed that whole-genome duplication (WGD) and dispersed duplication events were the main driving forces of PbrATG family expansion.Expression analysis of different pear tissues showed that all the genes were expressed in different pear tissues, and different PbrATGs are expressed at different times and in different locations. Moreover, all PbrATGs also responded to different abiotic stresses, especially salt and drought stress, which elicited the highest expression levels. Pear seedlings were subsequently infected with Botryosphaeria dothidea (B.dothidea). The results showed that different PbrATGs had different expression patterns at different infection stages. According to the gene expression data, PbrATG1a was selected as a key autophagy gene for further analysis. Silencing of PbrATG1a reduced the resistance of pear to B. dothidea, which resulted in increased lesions, reactive oxygen species (ROS) contents, antioxidant enzyme activity, and gene expression levels in the silenced pear seedlings after B. dothidea inoculation. In this study, a comprehensive bioinformatic analysis of ATGs was conducted, and the functions of PbrATGs in pear development and in response to stress were elucidated, which laid a foundation for further study of the molecular mechanism of autophagy and a new strategy for pear resistance breeding.展开更多
Apple ring rot,which is caused by Botryosphaeria dothidea,severely affects apple production.The mechanisms employed in apple cells against B.dothidea remain unknown.In this research,the pathogen infection mode and the...Apple ring rot,which is caused by Botryosphaeria dothidea,severely affects apple production.The mechanisms employed in apple cells against B.dothidea remain unknown.In this research,the pathogen infection mode and the relationship between cell death and disease resistance in‘Fuji’/B.dothidea interaction pathosystem were investigated.By using transmission electron microscopy(TEM),our research showed that the pathogen infects apple cells both intracellularly and extracellularly.However,compared with that in immature fruit,the incidence of hyphae in the interior of mature apple fruit cells increased dramatically,suggesting that cell wall-mediated penetration resistance could be important in apple resistance against B.dothidea.TEM ultrastructural characterization identified the nuclear morphology of programmed cell death induction in both apple fruit and callus cells under B.dothidea infection.Overexpression of MdVDAC2(MDP0000271281),which encodes an outer-membrane localized anion channel protein in mitochondria,significantly promoted cell death under B.dothidea infection and simultaneously inhibited pathogen infection,suggesting that cell death represents a disease resistance mechanism in apple against B.dothidea infection.Furthermore,BdCatalase(KAF4307763),a cytochromeP450 family protein BdCYP52A4(KAF4300696),and subtilisin-domain containing proteinswere identified fromB.dothidea-secreted proteins,which suggested the potential involvement of active oxygen species and phytoalexins in combating B.dothidea infection and triggering or dampening apple resistance.Collectively,our research suggested that cell wall-mediated penetration resistance,programmed cell death machinery and microbial effector-interrelated signaling were among strategies recruited in apple to combat B.dothidea.The current research laid the foundation for further investigations into resistance mechanisms in apple.展开更多
【目的】为了明确苹果轮纹病的病原葡萄座腔菌(Botryosphaeria dothidea(Moug.)Ces.et De Not.)的有性生殖阶段在我国是否发生及在我国苹果主产区的发生情况,【方法】2011年10月至2012年11月,对我国山东等8个苹果主产省市的38个果园进...【目的】为了明确苹果轮纹病的病原葡萄座腔菌(Botryosphaeria dothidea(Moug.)Ces.et De Not.)的有性生殖阶段在我国是否发生及在我国苹果主产区的发生情况,【方法】2011年10月至2012年11月,对我国山东等8个苹果主产省市的38个果园进行了调查与采样,对田间发现的子囊孢子通过形态观察、ITS序列的比对进行种类鉴定,并对子囊孢子进行了致病性测定。【结果】在北京、山东、河南、河北、陕西、山西和辽宁7个省市的20个果园的干腐型枯枝上发现了葡萄座腔菌的有性阶段,占调查省份的87.5%,占调查果园的52.6%;致病性测定结果显示,枯枝上形成的葡萄座腔菌的子囊孢子不仅可侵染苹果果实引起果腐,而且可侵染苹果枝条引起枝干溃疡。【结论】葡萄座腔菌的有性生殖在我国苹果主产区果园中发生普遍,子囊孢子不仅是葡萄座腔菌的一种越冬方式,也可以成为引起苹果轮纹病发生的初侵染源,在今后的轮纹病防治中,加强对苹果轮纹病田间干腐型枯枝的处理,将有助于提高病害防治效果。展开更多
Matrine is a promising botanical antifungal;however, the mechanism underlying the antifungal activity is yet limited. We studied the antifungal activity of matrine and the underlying mechanism in Botryosphaeria dothid...Matrine is a promising botanical antifungal;however, the mechanism underlying the antifungal activity is yet limited. We studied the antifungal activity of matrine and the underlying mechanism in Botryosphaeria dothidea as a model strain. Matrine strongly inhibited mycelial growth of B. dothidea in a dose-dependent manner. Matrine-treated B. dothidea showed morphological and ultrastructural alterations, including shriveled hyphae, plasmolysis, and leakage of cytoplasm related to cell membrane deterioration. In addition, matrine caused significantly high conductivity and absorbance (260 nm) in extracellular matrices and low lipid contents in B. dothidea, indicating increased membrane permeability. Lipid peroxidation showed that matrine resulted in increased malondialdehyde content while enhancing the generation of reactive oxygen species and the activities of superoxide dismutase, catalase, and peroxidase. These results showed that matrine inhibited the mycelial growth of B. dothidea by enhancing cell membrane permeability via membrane lipid peroxidation.展开更多
Botryosphaeria dothidea is a destructive fungal pathogen that causes Botryosphaeria canker and fruit ring rot on apple worldwide.Autophagy is a process of self-degradation that maintains intracellular homeostasis via ...Botryosphaeria dothidea is a destructive fungal pathogen that causes Botryosphaeria canker and fruit ring rot on apple worldwide.Autophagy is a process of self-degradation that maintains intracellular homeostasis via lysosomal pathway.To date,the biological role of autophagy in B.dothidea remains unknown.In this study,we identified and characterized the autophagy-related gene BdATG8 in B.dothidea.BdATG8 was able to restore the defect in nitrogen starvation tolerance of Saccharomyces cerevisiae ATG8 deletion mutant.GFP-BdAtg8 was shown to be a useful marker for monitoring autophagy in B.dothidea.Target deletion of Bd ATG8(ΔBd Atg8)blocked autophagy and significantly impaired mycelial growth,conidiation and perithecium formation.In addition,ΔBdAtg8 showed significantly increased sensitivity to phytoalexin and oxidative stress,suggesting that BdATG8 plays critical roles in overcoming phytoalexin and reactive oxygen species(ROS)-mediated plant immunity.Pathogenicity assays revealed thatΔBdAtg8 almost lost ability to infect hosts.Overall,our results indicate that BdATG8 plays an important role in fungal development,stress responses and pathogenesis in B.dothidea.展开更多
Sweet osmanthus is one of the ten traditional famous flowers in China.The occurrence of the diseases caused by fungi other than Botryosphaeria spp.has been reported mainly from China on sweet osmanthus.A leaf dieback ...Sweet osmanthus is one of the ten traditional famous flowers in China.The occurrence of the diseases caused by fungi other than Botryosphaeria spp.has been reported mainly from China on sweet osmanthus.A leaf dieback of sweet osmanthus caused by Botryosphaeria sp.was found for the first time in 2007 in Nanning City,Guangxi,China.The objectives of the present study were to isolate and characterize the causal organism of sweet osmanthus leaf dieback.The fungus was isolated from the lesions of affected sweet osmanthus leaves and its pathogenicity to sweet osmanthus was confirmed using a detached-leaf-inoculation method.The identification of the pathogen was carried out mainly based on the morphological characters and molecular analysis of internal transcribed spacer (ITS) sequences.The morphological characters of the pathogenic isolate GHX6 were agreed with that of Botryosphaeria dothidea.The ITS sequence of the isolate was amplified with primers ITS1 and ITS4,and submitted to GenBank (accession no.GQ368251).Molecular analysis based on ITS sequence comparison between the isolate GHX6 and the other related fungi derived from GenBank supported that the causal agent of the sweet osmanthus leaf dieback belonged to Botryosphaeria dothidea.This is the first report of Botryosphaeria dothidea causing leaf dieback on sweet osmanthus in China.展开更多
[Objective] The paper was to improve the antimicrobial effect of antagonistic Streptomyces on Botryosphaeria dothidea. [Method]Different concentrations of DES were adopted for mutagenic treatment of antagonistic Strep...[Objective] The paper was to improve the antimicrobial effect of antagonistic Streptomyces on Botryosphaeria dothidea. [Method]Different concentrations of DES were adopted for mutagenic treatment of antagonistic Streptomyces F-58. After fermentation,the mutant strain numbered F-58-06 with genetic stability and good antimicrobial effect was selected among 200 mutant strains; the biological activity of the strain was determined with B. dothidea as the indicator fungus,and the best concentration of DES was 2%. The fermentation conditions of antagonistic substances of Streptomyces strain F-58-06 produced in shake flasks were optimized using the method of single factor and orthogonal experimental design. [Result] The optimal fermentation conditions were carbon source corn flour,nitrogen source KNO_3,initial p H 7,loading volume 30 m L in 250 m L shake flask,inoculation volume 3%,incubation time 132 h. Based on orthogonal experiments,the best cultured medium ratio was corn flour 4%,KNO_30. 5%,Ca CO_30. 2%,Na Cl 0. 35%,Mg SO_4·7H_2O 0. 15%. [Conclusion]After mutation and optimization of culture medium,the antimicrobial activity of Streptomyces F-58 was greatly improved,and the average inhibition zone diameter was 1. 35 times of that of the original strain.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.31901989)Natural Science Foundation of Jiangsu Province (Grant No.BK20190534)+1 种基金China Postdoctoral Science Foundation (Grant No.2021T140332)Postgraduate Research&Practice Innovation Program of Jiangsu Province (Grant No.KYCX20_0584)。
文摘The pear is an economic fruit that is widely planted around the world and is loved by people for its rich nutritional value. Autophagy is a self-protection mechanism in eukaryotes, and its occurrence often accompanied by the degradation of damaged substances in cells and the recycling of nutrients. Autophagy is one of the mechanisms through which plants respond to environmental stress and plays an important role in plant development and stress resistance. Functional studies of autophagy-related genes (ATGs) have been performed on a variety of plant species, but little information is available on the ATG family in pear (Pyrus bretschneideri Rehd). Therefore, we analyzed the evolutionary dynamics and performed a genome-wide characterization of the PbrATG gene family. A total of 28 PbrATG members were identified.Phylogenetic analysis showed that PbrATGs were more closely related to ATGs of European pear and apple. Evolutionary analysis revealed that whole-genome duplication (WGD) and dispersed duplication events were the main driving forces of PbrATG family expansion.Expression analysis of different pear tissues showed that all the genes were expressed in different pear tissues, and different PbrATGs are expressed at different times and in different locations. Moreover, all PbrATGs also responded to different abiotic stresses, especially salt and drought stress, which elicited the highest expression levels. Pear seedlings were subsequently infected with Botryosphaeria dothidea (B.dothidea). The results showed that different PbrATGs had different expression patterns at different infection stages. According to the gene expression data, PbrATG1a was selected as a key autophagy gene for further analysis. Silencing of PbrATG1a reduced the resistance of pear to B. dothidea, which resulted in increased lesions, reactive oxygen species (ROS) contents, antioxidant enzyme activity, and gene expression levels in the silenced pear seedlings after B. dothidea inoculation. In this study, a comprehensive bioinformatic analysis of ATGs was conducted, and the functions of PbrATGs in pear development and in response to stress were elucidated, which laid a foundation for further study of the molecular mechanism of autophagy and a new strategy for pear resistance breeding.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFD1000307)the Natural Science Foundation in China(Grant Nos.31672136 and 31272132).
文摘Apple ring rot,which is caused by Botryosphaeria dothidea,severely affects apple production.The mechanisms employed in apple cells against B.dothidea remain unknown.In this research,the pathogen infection mode and the relationship between cell death and disease resistance in‘Fuji’/B.dothidea interaction pathosystem were investigated.By using transmission electron microscopy(TEM),our research showed that the pathogen infects apple cells both intracellularly and extracellularly.However,compared with that in immature fruit,the incidence of hyphae in the interior of mature apple fruit cells increased dramatically,suggesting that cell wall-mediated penetration resistance could be important in apple resistance against B.dothidea.TEM ultrastructural characterization identified the nuclear morphology of programmed cell death induction in both apple fruit and callus cells under B.dothidea infection.Overexpression of MdVDAC2(MDP0000271281),which encodes an outer-membrane localized anion channel protein in mitochondria,significantly promoted cell death under B.dothidea infection and simultaneously inhibited pathogen infection,suggesting that cell death represents a disease resistance mechanism in apple against B.dothidea infection.Furthermore,BdCatalase(KAF4307763),a cytochromeP450 family protein BdCYP52A4(KAF4300696),and subtilisin-domain containing proteinswere identified fromB.dothidea-secreted proteins,which suggested the potential involvement of active oxygen species and phytoalexins in combating B.dothidea infection and triggering or dampening apple resistance.Collectively,our research suggested that cell wall-mediated penetration resistance,programmed cell death machinery and microbial effector-interrelated signaling were among strategies recruited in apple to combat B.dothidea.The current research laid the foundation for further investigations into resistance mechanisms in apple.
文摘【目的】为了明确苹果轮纹病的病原葡萄座腔菌(Botryosphaeria dothidea(Moug.)Ces.et De Not.)的有性生殖阶段在我国是否发生及在我国苹果主产区的发生情况,【方法】2011年10月至2012年11月,对我国山东等8个苹果主产省市的38个果园进行了调查与采样,对田间发现的子囊孢子通过形态观察、ITS序列的比对进行种类鉴定,并对子囊孢子进行了致病性测定。【结果】在北京、山东、河南、河北、陕西、山西和辽宁7个省市的20个果园的干腐型枯枝上发现了葡萄座腔菌的有性阶段,占调查省份的87.5%,占调查果园的52.6%;致病性测定结果显示,枯枝上形成的葡萄座腔菌的子囊孢子不仅可侵染苹果果实引起果腐,而且可侵染苹果枝条引起枝干溃疡。【结论】葡萄座腔菌的有性生殖在我国苹果主产区果园中发生普遍,子囊孢子不仅是葡萄座腔菌的一种越冬方式,也可以成为引起苹果轮纹病发生的初侵染源,在今后的轮纹病防治中,加强对苹果轮纹病田间干腐型枯枝的处理,将有助于提高病害防治效果。
基金funded by the Special Fund for Forest-Scientific Research in the Public Interest(No.201304403-4)the Fundamental Research Funds for the Central Universities(2572015AA25)
文摘Matrine is a promising botanical antifungal;however, the mechanism underlying the antifungal activity is yet limited. We studied the antifungal activity of matrine and the underlying mechanism in Botryosphaeria dothidea as a model strain. Matrine strongly inhibited mycelial growth of B. dothidea in a dose-dependent manner. Matrine-treated B. dothidea showed morphological and ultrastructural alterations, including shriveled hyphae, plasmolysis, and leakage of cytoplasm related to cell membrane deterioration. In addition, matrine caused significantly high conductivity and absorbance (260 nm) in extracellular matrices and low lipid contents in B. dothidea, indicating increased membrane permeability. Lipid peroxidation showed that matrine resulted in increased malondialdehyde content while enhancing the generation of reactive oxygen species and the activities of superoxide dismutase, catalase, and peroxidase. These results showed that matrine inhibited the mycelial growth of B. dothidea by enhancing cell membrane permeability via membrane lipid peroxidation.
基金supported by the China Agriculture Research System of MOF and MARA(CARS-27)the National Natural Science Foundation of China(32001937)the Scientific Research Fund for High-level Talents in Qingdao Agricultural University,China(665/1120060)。
文摘Botryosphaeria dothidea is a destructive fungal pathogen that causes Botryosphaeria canker and fruit ring rot on apple worldwide.Autophagy is a process of self-degradation that maintains intracellular homeostasis via lysosomal pathway.To date,the biological role of autophagy in B.dothidea remains unknown.In this study,we identified and characterized the autophagy-related gene BdATG8 in B.dothidea.BdATG8 was able to restore the defect in nitrogen starvation tolerance of Saccharomyces cerevisiae ATG8 deletion mutant.GFP-BdAtg8 was shown to be a useful marker for monitoring autophagy in B.dothidea.Target deletion of Bd ATG8(ΔBd Atg8)blocked autophagy and significantly impaired mycelial growth,conidiation and perithecium formation.In addition,ΔBdAtg8 showed significantly increased sensitivity to phytoalexin and oxidative stress,suggesting that BdATG8 plays critical roles in overcoming phytoalexin and reactive oxygen species(ROS)-mediated plant immunity.Pathogenicity assays revealed thatΔBdAtg8 almost lost ability to infect hosts.Overall,our results indicate that BdATG8 plays an important role in fungal development,stress responses and pathogenesis in B.dothidea.
基金supported in part by the Youth Science Foundation of Guangxi, China (Gui-Ke-Qing 0728031)the Foundation for Returned Students of Guangxi, China (Gui-Ke-Hui 0639010)the Henan Provincial Key Subject Construction Program for Biochemical and Molecular Biology subsidized by Nanyang Normal University, China
文摘Sweet osmanthus is one of the ten traditional famous flowers in China.The occurrence of the diseases caused by fungi other than Botryosphaeria spp.has been reported mainly from China on sweet osmanthus.A leaf dieback of sweet osmanthus caused by Botryosphaeria sp.was found for the first time in 2007 in Nanning City,Guangxi,China.The objectives of the present study were to isolate and characterize the causal organism of sweet osmanthus leaf dieback.The fungus was isolated from the lesions of affected sweet osmanthus leaves and its pathogenicity to sweet osmanthus was confirmed using a detached-leaf-inoculation method.The identification of the pathogen was carried out mainly based on the morphological characters and molecular analysis of internal transcribed spacer (ITS) sequences.The morphological characters of the pathogenic isolate GHX6 were agreed with that of Botryosphaeria dothidea.The ITS sequence of the isolate was amplified with primers ITS1 and ITS4,and submitted to GenBank (accession no.GQ368251).Molecular analysis based on ITS sequence comparison between the isolate GHX6 and the other related fungi derived from GenBank supported that the causal agent of the sweet osmanthus leaf dieback belonged to Botryosphaeria dothidea.This is the first report of Botryosphaeria dothidea causing leaf dieback on sweet osmanthus in China.
基金Supported by Special Fund for Forestry Scientific Research in the Public Welfare(201204501)Key Theoretical Basis for Prevention and Control Technology of Forest Diseases and Pests & Key Science and Technology Project of Jilin Province(20110267)+1 种基金Research of New Antibiotics for Poplar Diseases & Science and Technology Research Plan of Forestry Department of Jilin Province(2014-004)Development of Forestry Microbial Agents & Key Projects for Science and Technology in Jilin Province(20150203015NY):Monitoring and Control Technology of Major Pests and Diseases in Industrial Forest
文摘[Objective] The paper was to improve the antimicrobial effect of antagonistic Streptomyces on Botryosphaeria dothidea. [Method]Different concentrations of DES were adopted for mutagenic treatment of antagonistic Streptomyces F-58. After fermentation,the mutant strain numbered F-58-06 with genetic stability and good antimicrobial effect was selected among 200 mutant strains; the biological activity of the strain was determined with B. dothidea as the indicator fungus,and the best concentration of DES was 2%. The fermentation conditions of antagonistic substances of Streptomyces strain F-58-06 produced in shake flasks were optimized using the method of single factor and orthogonal experimental design. [Result] The optimal fermentation conditions were carbon source corn flour,nitrogen source KNO_3,initial p H 7,loading volume 30 m L in 250 m L shake flask,inoculation volume 3%,incubation time 132 h. Based on orthogonal experiments,the best cultured medium ratio was corn flour 4%,KNO_30. 5%,Ca CO_30. 2%,Na Cl 0. 35%,Mg SO_4·7H_2O 0. 15%. [Conclusion]After mutation and optimization of culture medium,the antimicrobial activity of Streptomyces F-58 was greatly improved,and the average inhibition zone diameter was 1. 35 times of that of the original strain.
