The predominant causal agent of poplar leaf blight is the pathogenic fungus Alternaria alternata (Fr.) Keissl., which exhibits host specificity toward Populus species. To elucidate the molecular response mechanisms of...The predominant causal agent of poplar leaf blight is the pathogenic fungus Alternaria alternata (Fr.) Keissl., which exhibits host specificity toward Populus species. To elucidate the molecular response mechanisms of A. alternata under fludioxonil fungicide stress, the fungus was cultured at the half-maximal effective concentration (EC₅₀) of fludioxonil. Transcriptomic and metabolomic profiles were analyzed using mycelia harvested under these conditions. Comparative analysis revealed 1,001 differentially expressed genes (DEGs) in the resistant strain (RS) relative to the wild-type strain (WT), comprising 628 upregulated and 373 downregulated genes. Concurrently, 524 differentially accumulated metabolites (DAMs) were identified, with 336 upregulated and 188 downregulated metabolites. KEGG pathway enrichment demonstrated pronounced upregulation in glycerophospholipid metabolism, α-linolenic acid metabolism, nucleic acid biosynthesis, and glycosylation processes. Conversely, arachidonic acid and galactose metabolism pathways were suppressed. Significant downregulation was observed in phosphatidylinositol signaling, aflatoxin biosynthesis, and cutin/suberin/wax biosynthesis pathways. Transcriptomic profiling further indicated that upregulated DEGs were predominantly associated with amino sugar/nucleotide sugar metabolism, ABC transporters, aflatoxin biosynthesis, and purine metabolism, while downregulated DEGs were enriched in N-glycan biosynthesis, endoplasmic reticulum protein processing, steroid biosynthesis, and riboflavin metabolism. Fludioxonil exerted substantial inhibitory effects on fungal growth, pathogenicity, and metabolic activity. Mechanistically, A. alternata counteracted fungicide-induced stress through modulation of its antioxidant defense system. This integrative multi-omics study delineates the dynamic gene expression and metabolic reprogramming in A. alternata under fludioxonil exposure, providing novel insights into potential molecular targets and informing the development of next-generation fungicidal strategies for phytopathogen control.展开更多
Fungal diseases occur seriously in Pseudostellaria heterophylla in Qian- dongnan Prefecture of Guizhou Province from March to May every year. By field in- vestigation, tissue isolation and microscopic identification, ...Fungal diseases occur seriously in Pseudostellaria heterophylla in Qian- dongnan Prefecture of Guizhou Province from March to May every year. By field in- vestigation, tissue isolation and microscopic identification, the main pathogen was iden- tified as Rhizoctonia solanL the pathogen of damping-off disease. At the same time, Alternaria alternate was also isolated from the sampled diseased soil, and it has pathogenicity to Pseudostellaria heterophylla seedlings. The bio-control test showed that GH18 strain （Bacillus spp.） had significant inhibitory effects on Rhizoctonia solani and Alternaria alternate.展开更多
The ectomycorrhizal fungus Paxillus involutus was inoculated onto tissue-cultures of the hybrid poplar,Populus davidiana×P.bolleana,to evaluate the elemental defense effect to heavy metals copper and cadmium at d...The ectomycorrhizal fungus Paxillus involutus was inoculated onto tissue-cultures of the hybrid poplar,Populus davidiana×P.bolleana,to evaluate the elemental defense effect to heavy metals copper and cadmium at different concentrations by simulating Alternaria alternata fungus infection.The enrichment capacity of Populus davidiana×P.bolleana for Cu and Cd was closely associated with the degree of heavy metal stress.There was a significant positive interaction of applying Cu and Cd and the inoculation with P.involutus on A.alternata leaf blight disease index.The incidence rate and disease index of leaf blight underwent a significant reduction compared with the controls.Similarly,the ratio of the area of disease spot to leaf area,incidence rate,and disease index for Populus davidiana×P.bolleana leaves inoculated with Paxillus involutus(Batsch)Fr.were significantly lower than those of their nonmycorrhizal counterparts.With increasing the degree of Cu and Cd stress,a gradual increase in the average value of the membership function for the incidence rate and disease index was observed,indicating the weakened pathogen's ability to cause infection and the improved resistance of Populus davidiana×P.bolleana to leaf blight disease under Cu and Cd stress.Moreover,superoxide dismutase enzyme activity in Populus davidiana×P.bolleana increased significantly,reaching levels of 411.0 U/g FW and 421.6 U/g FW under Cu and Cd treatments,respectively.These changes in metabolic products and antioxidant enzyme activities suggest that P.involutus may enhance the resistance of Populus davidiana×P.bolleana to the fungus,Alternaria alternata Fr.Keissel under heavy metal stress by modulating these physiological indicators.展开更多
DNA was extracted from the strain of pathogen of poplar leaf blight using a modified CTAB method. ITS sequence （601bp） was initially amplified from the pathogen by using the universal primers ITSl and ITS4 （registe...DNA was extracted from the strain of pathogen of poplar leaf blight using a modified CTAB method. ITS sequence （601bp） was initially amplified from the pathogen by using the universal primers ITSl and ITS4 （registered No, DQ011257）. Comparing to the nucleotide sequences acquired from GenBank database, the strain is clustered into the homogeneity with Alternaria alternate （AY787684） and Alternaria alternate （AY354228）, with a homology of 98%, thus the strain was checked as Alternaria alternata （Fr.） Keissler. The optimal conditions for conidia germination and mycelium growth of the pathogen were tested, The optimal temperature for conidia germinating and mycelium growth is 25℃, and the optimal pH value is 6. Mycelium grows rather slowly at 10℃ and 30℃ and growth stops at above 35 ℃. Among the six culture mediums tested, PDA ＋ poplar leaf juice medium is most favorable for mycelium growth.展开更多
基金supported by the Northeast Asia Biodiversity Research Center(grant number 411147021003).
文摘The predominant causal agent of poplar leaf blight is the pathogenic fungus Alternaria alternata (Fr.) Keissl., which exhibits host specificity toward Populus species. To elucidate the molecular response mechanisms of A. alternata under fludioxonil fungicide stress, the fungus was cultured at the half-maximal effective concentration (EC₅₀) of fludioxonil. Transcriptomic and metabolomic profiles were analyzed using mycelia harvested under these conditions. Comparative analysis revealed 1,001 differentially expressed genes (DEGs) in the resistant strain (RS) relative to the wild-type strain (WT), comprising 628 upregulated and 373 downregulated genes. Concurrently, 524 differentially accumulated metabolites (DAMs) were identified, with 336 upregulated and 188 downregulated metabolites. KEGG pathway enrichment demonstrated pronounced upregulation in glycerophospholipid metabolism, α-linolenic acid metabolism, nucleic acid biosynthesis, and glycosylation processes. Conversely, arachidonic acid and galactose metabolism pathways were suppressed. Significant downregulation was observed in phosphatidylinositol signaling, aflatoxin biosynthesis, and cutin/suberin/wax biosynthesis pathways. Transcriptomic profiling further indicated that upregulated DEGs were predominantly associated with amino sugar/nucleotide sugar metabolism, ABC transporters, aflatoxin biosynthesis, and purine metabolism, while downregulated DEGs were enriched in N-glycan biosynthesis, endoplasmic reticulum protein processing, steroid biosynthesis, and riboflavin metabolism. Fludioxonil exerted substantial inhibitory effects on fungal growth, pathogenicity, and metabolic activity. Mechanistically, A. alternata counteracted fungicide-induced stress through modulation of its antioxidant defense system. This integrative multi-omics study delineates the dynamic gene expression and metabolic reprogramming in A. alternata under fludioxonil exposure, providing novel insights into potential molecular targets and informing the development of next-generation fungicidal strategies for phytopathogen control.
基金Supported by National Natural Science Foundation of China(31201160)Joint Fund of Science and Technology Department of Guizhou Province(QKH-J-LKK[2013]11)+1 种基金Agricultural and Forestry Diseases and Pests Identification and Control Science and Technology Innovation Team in Southeast Guizhou(QJHRCTD[2014]48)Excellent Scientific Research and Innovation Team Project of Science and Technology Department of Guizhou Province(QJHRCTD[2013]26)~~
文摘Fungal diseases occur seriously in Pseudostellaria heterophylla in Qian- dongnan Prefecture of Guizhou Province from March to May every year. By field in- vestigation, tissue isolation and microscopic identification, the main pathogen was iden- tified as Rhizoctonia solanL the pathogen of damping-off disease. At the same time, Alternaria alternate was also isolated from the sampled diseased soil, and it has pathogenicity to Pseudostellaria heterophylla seedlings. The bio-control test showed that GH18 strain （Bacillus spp.） had significant inhibitory effects on Rhizoctonia solani and Alternaria alternate.
基金supported by the National Natural Science Foundation of China(31800542)Natural Science Foundation of Heilongjiang Province(LH2023C105)Heilongjiang Research Institutes Basic Research Funding Project(LKSB2024-9)。
文摘The ectomycorrhizal fungus Paxillus involutus was inoculated onto tissue-cultures of the hybrid poplar,Populus davidiana×P.bolleana,to evaluate the elemental defense effect to heavy metals copper and cadmium at different concentrations by simulating Alternaria alternata fungus infection.The enrichment capacity of Populus davidiana×P.bolleana for Cu and Cd was closely associated with the degree of heavy metal stress.There was a significant positive interaction of applying Cu and Cd and the inoculation with P.involutus on A.alternata leaf blight disease index.The incidence rate and disease index of leaf blight underwent a significant reduction compared with the controls.Similarly,the ratio of the area of disease spot to leaf area,incidence rate,and disease index for Populus davidiana×P.bolleana leaves inoculated with Paxillus involutus(Batsch)Fr.were significantly lower than those of their nonmycorrhizal counterparts.With increasing the degree of Cu and Cd stress,a gradual increase in the average value of the membership function for the incidence rate and disease index was observed,indicating the weakened pathogen's ability to cause infection and the improved resistance of Populus davidiana×P.bolleana to leaf blight disease under Cu and Cd stress.Moreover,superoxide dismutase enzyme activity in Populus davidiana×P.bolleana increased significantly,reaching levels of 411.0 U/g FW and 421.6 U/g FW under Cu and Cd treatments,respectively.These changes in metabolic products and antioxidant enzyme activities suggest that P.involutus may enhance the resistance of Populus davidiana×P.bolleana to the fungus,Alternaria alternata Fr.Keissel under heavy metal stress by modulating these physiological indicators.
基金This paper was supported by National Natural Science Foundation of China （No.30271083）.
文摘DNA was extracted from the strain of pathogen of poplar leaf blight using a modified CTAB method. ITS sequence （601bp） was initially amplified from the pathogen by using the universal primers ITSl and ITS4 （registered No, DQ011257）. Comparing to the nucleotide sequences acquired from GenBank database, the strain is clustered into the homogeneity with Alternaria alternate （AY787684） and Alternaria alternate （AY354228）, with a homology of 98%, thus the strain was checked as Alternaria alternata （Fr.） Keissler. The optimal conditions for conidia germination and mycelium growth of the pathogen were tested, The optimal temperature for conidia germinating and mycelium growth is 25℃, and the optimal pH value is 6. Mycelium grows rather slowly at 10℃ and 30℃ and growth stops at above 35 ℃. Among the six culture mediums tested, PDA ＋ poplar leaf juice medium is most favorable for mycelium growth.
