Application of Bacillus subtilis NCD-2 can suppress cotton verticillium wilt and its effect on abundant and rare microbial communities in rhizosphere

Abstract

Bacillus subtilis NCD-2 (BS) shows prominent biological control for cotton verticillium wilt (CVW). However, it is unknown whether the effects on the abundant and rare microbial communities in rhizosphere after application of BS. Therefore, we investigated the effects of BS treatment on the suppression of CVW and the microbial community structure in rhizosphere. BS treatment successfully suppressed CVW, achieving a control effect of 61.60%, and cotton yield increased by 6.07% compared with blank control. Moreover, application of BS resulted in 28.17%, 18.63%, and 5.08% increases in plant fresh weight, dry weight, and number of branches, respectively. However, the populations of Verticillium dahliae in rhizosphere did not decrease by BS treatment. Microbial diversity analysis showed that soil bacterial and fungal diversities were increased under BS treatment. Principal component analyses revealed that BS had significantly effect on the abundant and rare microbial communities. Higher abundances of Acidobacteria, Chloroflexi, and Planctomycetes were observed among abundant bacterial taxa in the BS treatment. Furthermore, the abundances of Arenimonas, Hydrogenophaga, Chaetomium, Aspergillus, Nectria, Psathyrella, Conocybe, and Chrysosporium were also significantly higher than those in blank control. Redundancy analysis indicated that the microbial communities structure in BS treatment were positively related to ammonium nitrogen (NH4+-N), inorganic phosphorus (IP), and pH, but negatively to nitrate nitrogen (NO3–-N), AK, and organic matter (OM). These research results may offer theoretical bases for comprehensive the mechanism of ecological prevention and control CVW by application of BS.