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
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
[Objective]The paper was to study effect of Lupo compound microemulsion( LCW) on Alternaria alternata. [Method]The activity of spore germination and mycelial growth was investigated by filter paper method and mycelial...[Objective]The paper was to study effect of Lupo compound microemulsion( LCW) on Alternaria alternata. [Method]The activity of spore germination and mycelial growth was investigated by filter paper method and mycelial growth rate method,and field test was also conducted to determine the effect of LCW on tobacco plants. [Result]LCW could inhibit spore germination and mycelial growth of A. alternate. The higher concentration led to more severe reduction of sporulation and heavier inhibition against mycelial growth. When LCW was diluted into 200 times,inhibition rate of sporulation reached 91. 23%,and the inhibition rate of mycelial growth reached 93. 50%. Field test also proved that LCW had significant inhibitory effect on tobacco brown spot disease. [Conclusion]The study provided the reference for using botanical pesticide to control A. alternate in fields.展开更多
[Objective]The paper was to screen highly efficient fungicides for the prevention and control of tobacco brown spot(Alternaria alternata).[Method]The inhibitory effects of 12 chemical agents against A.alternata were d...[Objective]The paper was to screen highly efficient fungicides for the prevention and control of tobacco brown spot(Alternaria alternata).[Method]The inhibitory effects of 12 chemical agents against A.alternata were determined indoors by mycelium growth rate method.[Result]Toxicity test showed that 30%kresoxim-methyl·boscalid SC had the best inhibitory effect,with an EC_(50)of 1.05μg/mL,followed by 9%pyraclostrobin CS,with an EC_(50)of 2.09μg/mL.As a broad spectrum protective fungicide,77%copper calcium sulfate WP showed a low sensitivity against A.alternata in the petri dish test since it had a mechanism of action different from that of other chemical agents.[Conclusion]The study lays the foundation for subsequent screening of fungicides for the prevention and control of A.alternata in the field.展开更多
In the present study, histopathology of three varieties of sesame TS 3, TS 5 and SG 27 infected with Alternaria alternata was carried out to understand the mechanism of fungal infection and penetration in sesame plant...In the present study, histopathology of three varieties of sesame TS 3, TS 5 and SG 27 infected with Alternaria alternata was carried out to understand the mechanism of fungal infection and penetration in sesame plant as well as to determine the histological manifestation in sesame cells by light microscopy. Fungus was identified in infected tissues as a dark bluish black with toluidine blue O staining. Light microscopic examination of sesame stem showed that the fungus was present in epidermis, hypodermis and cortical parenchyma tissue as the symptoms became visible by naked eye ten days after inoculation (DAI). As the disease progress, the fungus moved from cortical parenchyma to vascular bundle, xylem and phloem. Later on, it completely overlapped the vascular bundle and entered in pith. When necrotic lesion appeared, fungus was present abundantly in epidermis, hypodermis, cortical parenchyma, vascular bundles and in pith. Due to its excessive growth and complete overlapping of cells, disorganization or destruction of cells of sesame took place. It was concluded that the Alternaria alternata was not a tissue limited pathogen instead of this it spread in to all tissues of stem from epidermis to pith.展开更多
Interestingly, antifungal protein AFP was purified from Aspergillus giganteus supernatants with modified isoelectric focusing procedure after adaptation of the secretion conditions. Subsequently, the antifungal activi...Interestingly, antifungal protein AFP was purified from Aspergillus giganteus supernatants with modified isoelectric focusing procedure after adaptation of the secretion conditions. Subsequently, the antifungal activity as well as the mode of action against Alternaria alternata was tested in vitro. Moreover, different concentrations of AFP were applied to banana fruits for 15 days at 20°C in vivo. Obtained results illustrated that A. giganteus was able to secrete about 39.78 ± 2.39 mg AFP·l-1 Olson medium. The employed ammonium sulfate (AS 75%) precipitation procedure followed by dialysis steps yielded about 16 - 22 mg AFP·l-1 culture supernatant with general mean of 18.67 ± 1.98 mg·l-1. The lost amount of AFP during purification using AS and 3KDa cut-off dialysis membrane is about 50% thus, purification procedure must be further improved. Indeed, concluded results from MIC and hyphal extension inhibition test noticed that AFP was efficiently affected by either growth or hyphae form of A. alternata in vitro. The MIC of AFP against A. alternata was 2μg·ml-1. However,short, thick and highly septated hyphae with damaged constricted apical regions extruding from condensed mycelium aggregates in treated hyphae compared to the untreated culture was remarkably shown. The mode of action of in vitro experiment manifested that AFP was effective to act the fungal cell and permeabilize the cell membrane of A. alternata. Furthermore, the in vivo experiment showed that AFP could reduce post-harvest decay on banana caused by A. alternata. AFP at concentration of 15 and 25 μg·ml-1 exhibit Alternaria decayed reduction by 45.45% and 77.27%, respectively. While no Alternaria decayed area was observed when 50 μg·ml-1 was applied during the storage time. Quantification of DNA by species-specific PCR could exude a positive correlation between the DNA amount and decayed area. In conclusion, AFP can be efficiently used as a bio-preservative agent during storage and handling of banana fruits, and considered as an excellent biological alternative to combat secondary growth of filamentous fungi.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.
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.
文摘[Objective]The paper was to study effect of Lupo compound microemulsion( LCW) on Alternaria alternata. [Method]The activity of spore germination and mycelial growth was investigated by filter paper method and mycelial growth rate method,and field test was also conducted to determine the effect of LCW on tobacco plants. [Result]LCW could inhibit spore germination and mycelial growth of A. alternate. The higher concentration led to more severe reduction of sporulation and heavier inhibition against mycelial growth. When LCW was diluted into 200 times,inhibition rate of sporulation reached 91. 23%,and the inhibition rate of mycelial growth reached 93. 50%. Field test also proved that LCW had significant inhibitory effect on tobacco brown spot disease. [Conclusion]The study provided the reference for using botanical pesticide to control A. alternate in fields.
基金Supported by Natural Science Foundation of Shandong ProvinceScience and Technology Project of Guizhou,Shaanxi and Sichuan Provincial Company of China National Tobacco Corporation(ZR2018BC037,201910,2019-ZY-1,SXYC-KJ-2017-01,SCYC201703)。
文摘[Objective]The paper was to screen highly efficient fungicides for the prevention and control of tobacco brown spot(Alternaria alternata).[Method]The inhibitory effects of 12 chemical agents against A.alternata were determined indoors by mycelium growth rate method.[Result]Toxicity test showed that 30%kresoxim-methyl·boscalid SC had the best inhibitory effect,with an EC_(50)of 1.05μg/mL,followed by 9%pyraclostrobin CS,with an EC_(50)of 2.09μg/mL.As a broad spectrum protective fungicide,77%copper calcium sulfate WP showed a low sensitivity against A.alternata in the petri dish test since it had a mechanism of action different from that of other chemical agents.[Conclusion]The study lays the foundation for subsequent screening of fungicides for the prevention and control of A.alternata in the field.
文摘In the present study, histopathology of three varieties of sesame TS 3, TS 5 and SG 27 infected with Alternaria alternata was carried out to understand the mechanism of fungal infection and penetration in sesame plant as well as to determine the histological manifestation in sesame cells by light microscopy. Fungus was identified in infected tissues as a dark bluish black with toluidine blue O staining. Light microscopic examination of sesame stem showed that the fungus was present in epidermis, hypodermis and cortical parenchyma tissue as the symptoms became visible by naked eye ten days after inoculation (DAI). As the disease progress, the fungus moved from cortical parenchyma to vascular bundle, xylem and phloem. Later on, it completely overlapped the vascular bundle and entered in pith. When necrotic lesion appeared, fungus was present abundantly in epidermis, hypodermis, cortical parenchyma, vascular bundles and in pith. Due to its excessive growth and complete overlapping of cells, disorganization or destruction of cells of sesame took place. It was concluded that the Alternaria alternata was not a tissue limited pathogen instead of this it spread in to all tissues of stem from epidermis to pith.
文摘Interestingly, antifungal protein AFP was purified from Aspergillus giganteus supernatants with modified isoelectric focusing procedure after adaptation of the secretion conditions. Subsequently, the antifungal activity as well as the mode of action against Alternaria alternata was tested in vitro. Moreover, different concentrations of AFP were applied to banana fruits for 15 days at 20°C in vivo. Obtained results illustrated that A. giganteus was able to secrete about 39.78 ± 2.39 mg AFP·l-1 Olson medium. The employed ammonium sulfate (AS 75%) precipitation procedure followed by dialysis steps yielded about 16 - 22 mg AFP·l-1 culture supernatant with general mean of 18.67 ± 1.98 mg·l-1. The lost amount of AFP during purification using AS and 3KDa cut-off dialysis membrane is about 50% thus, purification procedure must be further improved. Indeed, concluded results from MIC and hyphal extension inhibition test noticed that AFP was efficiently affected by either growth or hyphae form of A. alternata in vitro. The MIC of AFP against A. alternata was 2μg·ml-1. However,short, thick and highly septated hyphae with damaged constricted apical regions extruding from condensed mycelium aggregates in treated hyphae compared to the untreated culture was remarkably shown. The mode of action of in vitro experiment manifested that AFP was effective to act the fungal cell and permeabilize the cell membrane of A. alternata. Furthermore, the in vivo experiment showed that AFP could reduce post-harvest decay on banana caused by A. alternata. AFP at concentration of 15 and 25 μg·ml-1 exhibit Alternaria decayed reduction by 45.45% and 77.27%, respectively. While no Alternaria decayed area was observed when 50 μg·ml-1 was applied during the storage time. Quantification of DNA by species-specific PCR could exude a positive correlation between the DNA amount and decayed area. In conclusion, AFP can be efficiently used as a bio-preservative agent during storage and handling of banana fruits, and considered as an excellent biological alternative to combat secondary growth of filamentous fungi.
