Genotype-Dependent Responses of Pepper Endophytes to Soil Microbial Community Shifts Induced by Allyl Isothiocyanate Fumigation

Wenfeng Tian^1,2Qiuxia Wang²Aocheng Cao²Dongdong Yan²Yuan Li²Zhoubin Liu^1*Yang Bozhi^1*Wensheng Fang^2*

• ¹Hunan Agricultural University, Changsha, Hunan, China
• ²Chinese Academy of Agricultural Sciences (CAAS), Beijing, China

Allyl isothiocyanate demonstrates efficacy as a soil fumigant, exerting substantial control over soilborne pathogens and nematodes. Soil microbial diversity and composition affect crop growth and health, but whether soil microbial community changes cause crop endophyte changes are unknown. In this study, allyl isothiocyanate was used to fumigate the soil, and the response of endophytic bacteria of different genotypes (Xiangla359, La Xuan, Shuang Jiao) was investigated. The results showed that allyl isothiocyanate fumigation significantly increased soil microbial community diversity, stimulated the growth of Actinomycetota, and inhibited the growth of Pseudomonadota. However, the effects of allyl isothiocyanate on endophytic bacteria of capsicum varied according to variety. For example, fumigation significantly reduced the microbial diversity in the root and leaves of Xiangla359, but had no significant effect on La Xuan and Shuang Jiao. Correspondingly, soil fumigant allyl isothiocyanate had different growth promotion effects on the three varieties of pepper after disinfection, and the promotion effect on Xiangla359 the largest. Our results suggest that although allyl isothiocyanate fumigation significantly alters soil microbial community diversity and structural composition, the effects on crop endophytes are highly dependent on crop genotypes.