The soil-borne fungal pathogen Verticillium Iongisporum causes vascular disease on Brassicaceae host plants such as oilseed rape. The fungus colonizes the root xylem and moves upwards to the foliage where disease symp...The soil-borne fungal pathogen Verticillium Iongisporum causes vascular disease on Brassicaceae host plants such as oilseed rape. The fungus colonizes the root xylem and moves upwards to the foliage where disease symptoms become visible. Using Arabidopsis as a model for early gene induction, we performed root transcriptome analyses in re- sponse to hyphal growth immediately after spore germination and during penetration of the root cortex, respectively. Infected roots showed a rapid reprogramming of gene expression such as activation of transcription factors, stress-, and defense-related genes. Here, we focused on the highly coordinated gene induction resulting in the production of tryp- tophan-derived secondary metabolites. Previous studies in leaves showed that enzymes encoded by CYP81F2 and PEN2 （PENETRATION2） execute the formation of antifungal indole glucosinolate （IGS） metabolites. In Verticillium-infected roots, we found transcriptional activation of CYP81F2 and the PEN2 homolog PEL 1 （PEN2-LIKE1）, but no increase in antifungal IGS breakdown products. In contrast, indole-3-carboxylic acid （13CA） and the phytoalexin camalexin accumulated in infected roots but only camalexin inhibited Verticillium growth in vitro. Whereas genetic disruption of the individual metabolic pathways leading to either camalexin or CYP81F2-dependent IGS metabolites did not alter Verticillium-induced disease symptoms, a cyp79b2 cyp79b3 mutant impaired in both branches resulted in significantly enhanced susceptibility. Hence, our data provide an insight into root-specific early defenses and suggest tryptophan-derived metabolites as active anti- fungal compounds against a vascular pathogen.展开更多
Nutrient acquisition through symbiotic ectomycorrhizal fungi is carbon(C)costly but fundamental for plant growth,community,and ecosystem functioning.Here,we examined the functions of roots and mycorrhiza with respect ...Nutrient acquisition through symbiotic ectomycorrhizal fungi is carbon(C)costly but fundamental for plant growth,community,and ecosystem functioning.Here,we examined the functions of roots and mycorrhiza with respect to nutrient uptake after artificially inducing C limitation-seven months after girdling of an ectomycorrhizal tree,Pinus taeda.Root physiological activity(measured as root nitrogen content and root exudation)declined after girdling and was accompanied with 110%and 340%increases in mycorrhizal colonization and extramatrical hyphal length,respectively.Fungi colonizing roots switched to a community characterized by higher C efficiency(lower C cost)of nutrient acquisition(CENA,the amount of nutrient acquisition per unit C cost)and lower network complexity,indicating a tradeoff between CENA and stability of the fungal community.Root transcriptome analysis suggested a shift in metabolic pathways from a tricarboxylic acid cycle decomposition of carbohydrate to lipid biosynthesis to maintain closer associations with mycorrhiza for nutrient cycling after the girdling.By integrating multi-level evidence,including root transcriptome,fungal composition,and network complexity data,we demonstrate an increased dependence on mycorrhiza for nutrient acquisition under the C limitation condition,which is likely due to a shift to fungal community with higher CENA at the cost of lower stability.展开更多
文摘The soil-borne fungal pathogen Verticillium Iongisporum causes vascular disease on Brassicaceae host plants such as oilseed rape. The fungus colonizes the root xylem and moves upwards to the foliage where disease symptoms become visible. Using Arabidopsis as a model for early gene induction, we performed root transcriptome analyses in re- sponse to hyphal growth immediately after spore germination and during penetration of the root cortex, respectively. Infected roots showed a rapid reprogramming of gene expression such as activation of transcription factors, stress-, and defense-related genes. Here, we focused on the highly coordinated gene induction resulting in the production of tryp- tophan-derived secondary metabolites. Previous studies in leaves showed that enzymes encoded by CYP81F2 and PEN2 （PENETRATION2） execute the formation of antifungal indole glucosinolate （IGS） metabolites. In Verticillium-infected roots, we found transcriptional activation of CYP81F2 and the PEN2 homolog PEL 1 （PEN2-LIKE1）, but no increase in antifungal IGS breakdown products. In contrast, indole-3-carboxylic acid （13CA） and the phytoalexin camalexin accumulated in infected roots but only camalexin inhibited Verticillium growth in vitro. Whereas genetic disruption of the individual metabolic pathways leading to either camalexin or CYP81F2-dependent IGS metabolites did not alter Verticillium-induced disease symptoms, a cyp79b2 cyp79b3 mutant impaired in both branches resulted in significantly enhanced susceptibility. Hence, our data provide an insight into root-specific early defenses and suggest tryptophan-derived metabolites as active anti- fungal compounds against a vascular pathogen.
基金funded by the National Natural Science Foundation of China(32471824,32171746,42077450,31870522,31670550,42122054)the leading talents of basic research in Henan Province,the Scientific Research Foundation of Henan Agricultural University(30500854)+4 种基金Excellent Youth Creative Research Group Project in Henan Province(252300421002)Foreign Scientists Studio in Henan province(GZS2025011)the Funding for Characteristic and Backbone Forestry Discipline Group of Henan Province,Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control(2023B1212060002)Guangdong Basic and Applied Basic Research Foundation(2021B1515020082)the RUDN University Strategic Academic Leadership Program,Funding for Characteristic and backbone forestry discipline group of Henan Province and Research Funds for overseas returnee in Henan Province,China.We thank Editage Service in improving the English language.
文摘Nutrient acquisition through symbiotic ectomycorrhizal fungi is carbon(C)costly but fundamental for plant growth,community,and ecosystem functioning.Here,we examined the functions of roots and mycorrhiza with respect to nutrient uptake after artificially inducing C limitation-seven months after girdling of an ectomycorrhizal tree,Pinus taeda.Root physiological activity(measured as root nitrogen content and root exudation)declined after girdling and was accompanied with 110%and 340%increases in mycorrhizal colonization and extramatrical hyphal length,respectively.Fungi colonizing roots switched to a community characterized by higher C efficiency(lower C cost)of nutrient acquisition(CENA,the amount of nutrient acquisition per unit C cost)and lower network complexity,indicating a tradeoff between CENA and stability of the fungal community.Root transcriptome analysis suggested a shift in metabolic pathways from a tricarboxylic acid cycle decomposition of carbohydrate to lipid biosynthesis to maintain closer associations with mycorrhiza for nutrient cycling after the girdling.By integrating multi-level evidence,including root transcriptome,fungal composition,and network complexity data,we demonstrate an increased dependence on mycorrhiza for nutrient acquisition under the C limitation condition,which is likely due to a shift to fungal community with higher CENA at the cost of lower stability.
