Resistance to Aphid (Macrosiphoniella sanbourni) and Antifungal Activities of Volatile Organic Compounds from Artimisia and Tanacetum Species

Species from genus of Artimisia and Tanacetum , closely related to Chrysanthemum , are potential parents for improving the resistance of cultivated chrysanthemums due to their resistance to pests and pathogens. In present study, we aimed to identify the aphid and pathogen resistant species by evaluating their volatile compounds' antifungal properties and aphid infestation resistance. The antifungal activity of volatile components showed that the leave and stem volatiles of A. sacrorum had the strongest antifungal effect against Alternaria alternata , with inhibition rates reaching 93.58% and 92.66%, respectively. The stem volatiles of T. vulgare had the strongest antifungal activity against Colletortrichum siamense , with inhibition rate up to 29.10%. Choice and no-choice assays showed that all tested six closely related species had strong repellent and antifeedant effects on aphid ( Macrosiphoniella sanbourni ) compared to Chrysanthemum morifolium ‘Qi Yue Bai’. Discriminating Partial Least Squares Analysis (PLS-DA) and Discriminating Analysis of Orthogonal Partial Least Squares (OPLS-DA) separated the samples into different groups. β-Ylangene, β-copaene and ε-muurolene were associated with the antifungal activity against A. alternata . β-Terpinene and β-myrcene were associated with the antifungal activity against C. siamense . Scopoletin, eucalyptol, thujone, camphor and β-thujene were associated with aphid resistance. These metabolites were chemical marker candidates for resistance to biotic stress in closely related species to Chrysanthemums , and A. rubripes , T. vulgare and A. sacrorum are potential parental materials for Chrysanthemum breeding for disease and pest resistance.