Allelopathy of root exudates from different resistant eggplants to Verticillium dahliae and the identification of allelochemicals
Three eggplant cultivars were inoculated with Verticillium dahliae Kleb. to assess their resistance to Verticillium wilt. Solanum tor was resistant, “Liyuanziqie” was tolerant, and “Xi’anlvqie” susceptible. The disease incidence and disease index of Verticillium wilt and the amount of V. dahliae in rhizospheric soil, variation of microbial composition, the allelopathy of root exudates to mycelium growth of V. dahliae and the chemical substances of root exudates from eggplant cultivars with different resistance to Verticillium wilt were investigated in this experiment. The results showed that the root exudates of resistant type could not only affect the growth and development of V. dahliae, but also influence V. dahliae indirectly through regulating soil microbial community composition. This may be one of the reasons for the increase of disease resistance. However, the susceptible type exhibited an opposite trend. It was inferred that the resistant type contained some particular components, such as acohd, amide, pyranoid, fluorene, while the susceptible one comprised more types of components, that is, ketone, phenol, ester and phenolic acid.
Key words: Allelopathy, allelochemical, root exudates, eggplant, Verticillium dahliae, Verticillium wilt, microbial composition.