Apple leaf spot,caused by the Alternaria alternata apple pathotype(AAAP),is an important fungal disease of apple.To understand the molecular basis of resistance and pathogenesis in apple leaf spot,the transcriptomes o...Apple leaf spot,caused by the Alternaria alternata apple pathotype(AAAP),is an important fungal disease of apple.To understand the molecular basis of resistance and pathogenesis in apple leaf spot,the transcriptomes of two apple cultivars‘Hanfu'(HF)(resistant)and‘Golden Delicious'(GD)(susceptible)were analyzed at 0,6,18,24 and 48 h after AAAP inoculation by RNA-Seq.At each time point,a large number of significantly differentially expressed genes(DEGs)were screened between AAAP-inoculated and uninoculated apple leaves.Analysis of the common DEGs at four time points revealed significant differences in the resistance of‘HF'and‘GD'apple to AAAP infection.RLP,RNL,and JA signal-related genes were upregulated in both cultivars to restrict AAAP development.However,genes encoding CNLs,TNLs,WRKYs,and AP2s were only activated in‘HF'as part of the resistance response,of which,some play major roles in the regulation of ET and SA signal transduction.Further analysis showed that many DEGs with opposite expression trends in the two hosts may play important regulatory roles in response to AAAP infection.Transient expression of one such gene MdERF110 in‘GD'apple leaves improved AAAP resistance.Collectively,this study highlights the reasons for differential resistance to AAAP infection between‘HF'and‘GD'apples which can theoretically assist the molecular breeding of disease-resistant apple crops.展开更多
[Objectives]The paper was to identify Alternaria alternata causing leaf spot disease on Huangdi banana in China.[Methods]Fungal isolates were isolated and identified by morphological features,molecular identification ...[Objectives]The paper was to identify Alternaria alternata causing leaf spot disease on Huangdi banana in China.[Methods]Fungal isolates were isolated and identified by morphological features,molecular identification and pathogenicity test.[Results]There were light to dark brown,tiny oval spots on leaves.The causal agent isolated from affected leaves was identified as A.alternata based on the morphological properties,coupled with sequence analyses of the internal transcribed spacer(ITS)region,large subunit ribosomal DNA(LSU rDNA)and the translation elongation factor 1-alpha(TEF-1α)gene.Koch s postulates were fulfilled by successful re-isolation of pathogen from the artificial inoculated leaves.[Conclusions]To our knowledge,this is the first report of leaf spot caused by A.alternata on Huangdi banana in China.The identification of A.alternata as the causal agent of the observed leaf spot disease on Huangdi banana is critical to the prevention and control of this disease in the future.展开更多
【目的】研究促分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)信号通路对Alternaria alternata响应梨果皮蜡质疏水性、化学组分及乙烯信号的调控作用.【方法】采用药理学方法,以MAPK信号通路专一性抑制剂SB203580处理A.al...【目的】研究促分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)信号通路对Alternaria alternata响应梨果皮蜡质疏水性、化学组分及乙烯信号的调控作用.【方法】采用药理学方法,以MAPK信号通路专一性抑制剂SB203580处理A.alternata孢子悬浮液,研究了MAPK在A.alternata致病性中的作用,同时结合体外试验,分析了MAPK信号通路在A.alternata响应疏水性、梨果蜡质提取物和外源乙烯等刺激进而启动后孢子萌发和附着胞形成中的作用.【结果】SB203580处理显著地抑制损伤接种梨果黑斑病的扩展.体外试验表明,外源信号均能显著地诱导A.alternata孢子萌发和附着胞的形成,而SB203580处理显著地抑制了其诱导作用,尤其对A.alternata附着胞形成的抑制更为明显,处理后8 h,抑制剂对A.alternata在高疏水表面、梨果蜡质提取物及外源乙烯等外源信号处理表面的附着胞形成的抑制率分别为22.85%、20.71%和17.61%(P<0.05).【结论】通过药理学方法得知MAPK信号通路可通过调控A.alternata孢子萌发和附着胞形成,进而识别和响应梨果皮物理化学信号.展开更多
Effects of different polarity solvents on the ultrastructure and chemical composition of cuticular wax in Pingguoli pear as well as their bioactive role against Alternaria alternate were studied and the results showed...Effects of different polarity solvents on the ultrastructure and chemical composition of cuticular wax in Pingguoli pear as well as their bioactive role against Alternaria alternate were studied and the results showed that the highest wax content was extracted with chloroform, and its wax content was up to 322.2 gg cm2. Long-chain fatty acids predominated in menthol extracts and n-alkanes were predominant in wax extracted with ether, chloroform and n-hexane. Pingguoli pear fruit surface was covered by a smooth and amorphous wax layer with small, scattered crystal. The morphology of recrystallized wax in vitro after removal with different solvents was not similar to that of the intact fruit surface. Removal of cuticular wax with various solvents significantly enhanced A. alternata infection, except for wax removed by methanol. The solvent extracts of methanol and chloroform stimulated the spore germination and mycelium growth ofA. alternata, but the ether and n-hexane extracts showed antifungal activity.展开更多
The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high lev...The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate （filtrate to fungal spores inocula mixed in proportion 1 ： 50）. These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.32202463)China Agriculture Research System(Grant No.CARS-27)the Agricultural Science and Technology Innovation Program(Grant No.CAAS-ASTIP-2021-RIP-02)。
文摘Apple leaf spot,caused by the Alternaria alternata apple pathotype(AAAP),is an important fungal disease of apple.To understand the molecular basis of resistance and pathogenesis in apple leaf spot,the transcriptomes of two apple cultivars‘Hanfu'(HF)(resistant)and‘Golden Delicious'(GD)(susceptible)were analyzed at 0,6,18,24 and 48 h after AAAP inoculation by RNA-Seq.At each time point,a large number of significantly differentially expressed genes(DEGs)were screened between AAAP-inoculated and uninoculated apple leaves.Analysis of the common DEGs at four time points revealed significant differences in the resistance of‘HF'and‘GD'apple to AAAP infection.RLP,RNL,and JA signal-related genes were upregulated in both cultivars to restrict AAAP development.However,genes encoding CNLs,TNLs,WRKYs,and AP2s were only activated in‘HF'as part of the resistance response,of which,some play major roles in the regulation of ET and SA signal transduction.Further analysis showed that many DEGs with opposite expression trends in the two hosts may play important regulatory roles in response to AAAP infection.Transient expression of one such gene MdERF110 in‘GD'apple leaves improved AAAP resistance.Collectively,this study highlights the reasons for differential resistance to AAAP infection between‘HF'and‘GD'apples which can theoretically assist the molecular breeding of disease-resistant apple crops.
基金Supported by China Agriculture Research System(CARS-31).
文摘[Objectives]The paper was to identify Alternaria alternata causing leaf spot disease on Huangdi banana in China.[Methods]Fungal isolates were isolated and identified by morphological features,molecular identification and pathogenicity test.[Results]There were light to dark brown,tiny oval spots on leaves.The causal agent isolated from affected leaves was identified as A.alternata based on the morphological properties,coupled with sequence analyses of the internal transcribed spacer(ITS)region,large subunit ribosomal DNA(LSU rDNA)and the translation elongation factor 1-alpha(TEF-1α)gene.Koch s postulates were fulfilled by successful re-isolation of pathogen from the artificial inoculated leaves.[Conclusions]To our knowledge,this is the first report of leaf spot caused by A.alternata on Huangdi banana in China.The identification of A.alternata as the causal agent of the observed leaf spot disease on Huangdi banana is critical to the prevention and control of this disease in the future.
文摘【目的】研究促分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)信号通路对Alternaria alternata响应梨果皮蜡质疏水性、化学组分及乙烯信号的调控作用.【方法】采用药理学方法,以MAPK信号通路专一性抑制剂SB203580处理A.alternata孢子悬浮液,研究了MAPK在A.alternata致病性中的作用,同时结合体外试验,分析了MAPK信号通路在A.alternata响应疏水性、梨果蜡质提取物和外源乙烯等刺激进而启动后孢子萌发和附着胞形成中的作用.【结果】SB203580处理显著地抑制损伤接种梨果黑斑病的扩展.体外试验表明,外源信号均能显著地诱导A.alternata孢子萌发和附着胞的形成,而SB203580处理显著地抑制了其诱导作用,尤其对A.alternata附着胞形成的抑制更为明显,处理后8 h,抑制剂对A.alternata在高疏水表面、梨果蜡质提取物及外源乙烯等外源信号处理表面的附着胞形成的抑制率分别为22.85%、20.71%和17.61%(P<0.05).【结论】通过药理学方法得知MAPK信号通路可通过调控A.alternata孢子萌发和附着胞形成,进而识别和响应梨果皮物理化学信号.
基金financially supported by the National Natural Sciences Foundation of China (30960243 and 31260494)the Fuxi Distinguished Young Talent Cultivation Project of Gansu Agricultural University, China
文摘Effects of different polarity solvents on the ultrastructure and chemical composition of cuticular wax in Pingguoli pear as well as their bioactive role against Alternaria alternate were studied and the results showed that the highest wax content was extracted with chloroform, and its wax content was up to 322.2 gg cm2. Long-chain fatty acids predominated in menthol extracts and n-alkanes were predominant in wax extracted with ether, chloroform and n-hexane. Pingguoli pear fruit surface was covered by a smooth and amorphous wax layer with small, scattered crystal. The morphology of recrystallized wax in vitro after removal with different solvents was not similar to that of the intact fruit surface. Removal of cuticular wax with various solvents significantly enhanced A. alternata infection, except for wax removed by methanol. The solvent extracts of methanol and chloroform stimulated the spore germination and mycelium growth ofA. alternata, but the ether and n-hexane extracts showed antifungal activity.
基金State Tobacco Monopoly Administration of China (110200201008)
文摘The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate （filtrate to fungal spores inocula mixed in proportion 1 ： 50）. These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.
