The control effect of endophytic fungus Fusarium equiseti FUS-8 on cotton Verticillium wilt and its effects on soil microbial communities

Cotton Verticillium wilt is a very serious soil-borne disease caused mainly by Verticillium dahliae, which severely affects the yield and quality of cotton. There has been an increasing amount of research on the biocontrol of plant disease; however, there is still a lack of effective biocontrol strains.

In this study, antagonistic endophytic fungi were screened to inhibit V. dahliae, and soil microbiome technologies were used to characterize the biocontrol mechanism.

The strain FUS-8 was isolated from cotton stems; the strain significantly inhibited the growth of V. dahliae and was identified as Fusarium equiseti. FUS-8 had a small amount of cellulase activity, and its fermentation broth significantly inhibited the sporulation and colony formation of V. dahliae. After inoculation with FUS-8 in the greenhouse and field, the disease index significantly decreased. Preinoculation with FUS-8 inhibited the expression of pod. FUS-8 colonized the roots, hypocotyls, and stems of cotton. After preinoculation with FUS-8 in the greenhouse, the Shannon and Sobs indices of fungi and bacteria significantly decreased. The abundance of Bacillus genus in the treatment group was significantly greater than that in the control group 4 days after preinoculation with FUS-8 and 14 days after inoculation with V991. The LDA value of Bacillus in the treatment group was the highest at the genus level after inoculation with FUS-8 only; after reinoculation with V991, Pseudoxanthomonas had the highest LDA value in the treatment group.

FUS-8 altered soil microbial communities, enriched beneficial bacteria, and reduced the incidence of cotton Verticillium wilt.