Terpenoids are a class of structurally diverse natural products involved in various plant biological processes. Their primary function is believed to provide chemical defense against natural enemies. However, the understanding of the role of terpenoids in plant defense against fungal pathogens is very limited.
This research analyzes the correlation between terpenoids and defense against a black spot disease-causing fungal pathogen Alternaria tenuissima in the ornamental plant Chrysanthemum morifolium. Five cultivars of C. morifolium were compared for their defense against A. tenuissima infection and ranked as resistant and susceptible based on the sizes of leaf lesion after infection. Analysis of the leaf extracts revealed a significant negative correlation between the content of terpenes 1,8-cineole, E-β-caryophyllene, β-copaene, and γ-muurolene and damaged leaf area in the cultivars. Besides, A. tenuissima infection induced the emission of terpenoid volatiles.
The cultivar with a higher level of resistance and high contents of terpenoids released less volatiles upon A. tenuissima infection than the cultivars with a lower level of resistance. In conclusion, this study uncovers the complex relationship between the constitutively produced and induced terpenoids and their role in defense against the fungal pathogen A. tenuissima in C. morifolium.
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He, Xi & Jiang, Yifan & Chen, Sumei & Chen, Feng. (2022). Terpenoids and Their Possible Role in Defense Against a Fungal Pathogen Alternaria tenuissima in Chrysanthemum morifolium Cultivars. Journal of Plant Growth Regulation. 10.1007/s00344-022-10619-z.