Phytohormonal and metabolism analysis of Brassica rapa L. ssp. Pekinensis with different resistance during Plasmodiophora brassicae infection

[摘要] Clubroot of Chinese cabbage ( Brassica rapa L. ssp. pekinensis ), caused by the obligate parasite Plasmodiophora brassicae , accounts for serious yield losses. The aim of our study was to explore the phytohormone levels and metabolome changes in the roots of resistant and susceptible B. rapa genotypes at a late stage of infection, i.e., 28 days post-infection. Both genotypes showed decreased auxin levels after P. brassicae infection except for indole-3-acetic acid. Overall, the susceptible genotype had higher auxin and cytokinin levels after infection, with the exception of trans-zeatin and 3- indolebutyric acid as compared to the resistant genotype. Jasmonic acid levels declined after infection regardless of the genotype. Resistance against clubroot was evident with the increased levels of salicylic acid in the resistant genotype. The susceptible genotype had a higher number of differentially accumulated metabolites (DAMs) (262) than the resistant genotype (238) after infection. Interestingly, 132 DAMs were commonly detected in both genotypes when infected with the pathogen, belonging to metabolite classes such as phenolic acids, amino acids, and derivatives, glucosinolates, organic acids, flavonoids, nucleotides and derivatives, and fatty acids. The differential metabolite analysis revealed that metabolites related to amino acid biosynthesis, fatty acid biosynthesis and elongation, glutathione metabolism, and glucosinolate metabolism were highly accumulated in the resistant genotype, suggesting their essential roles in resistance against P. brassicae infection.

[学科分类] 仪器

[关键词] Auxins;Brassicaceae;Clubroot;Cytokinins;Fatty acids;Glucosinolates;Glutathione;Salicylic acid;Jasmonic acid