Eggplant by grafting enhanced with biochar recruits specific microbes for disease suppression of Verticillium wilt

Abstract

The suppressiveness of soils to inhibit pathogens mostly require rich microbiome harbouring plant growth-promoting microbes in the soil, especially rhizosphere. The present study evaluates the suppressiveness of the rhizosphere of a grafted eggplant under biochar amendment and its effects on the microbial communities involved. This study used four treatments consisting of grafted (CB) and self-rooted (CA) eggplants, with 10 t/ha biochar addition each (as BB and BA). Results revealed that BB significantly suppressed the incidence of Verticillium wilt by more than 70% and improved the yield of eggplant compared with the control. Treatment of CB and BB showed significant effects on the community structure and abundance of bacteria and fungi. The bacteria diversity and richness of CB and BB were higher than those of the BA and CA, respectively. For bacteria, the analysis showed the genus Bacillus to be abundant in the rhizosphere of both CB and BB, while genera Humicola, Chaetomium, Mortierella, and Tausonia were the dominant fungi, suggesting they may play an active part in disease suppression. Based on Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis, the results showed that CB and BB harbored more genes responsible for disease resistance than CA and BA. In summary, grafting with the addition of biochar was effective in suppressing Verticillium wilt of eggplant and can be given as a recommendation to eggplant growers to alleviate Verticillium wilt.