Rhizosphere bacterial community in watermelon-wheat intercropping was more stable than in watermelon monoculture system under Fusarium oxysporum f. sp. niveum invasion

Abstract

Although intercropping and pathogen invasion can affect the plant rhizosphere bacterial community, how intercropping affects the rhizosphere bacterial community in response to pathogen invasion is poorly understood. The root system of watermelon was separated into two halves and placed in separate pots for Fusarium oxysporum f. sp. niveum(FON) inoculation and wheat intercropping. Responses of the watermelon rhizosphere bacterial community to wheat intercropping and FON inoculation were analyzed by high-throughput sequencing. Wheat intercropping did not affect the diversity but altered the composition of rhizosphere bacterial community on both sides of watermelon roots. In watermelon monoculture, FON inoculation increased the diversity of the rhizosphere bacterial community and stimulated certain potentially plant beneficial bacteria. The effects of FON inoculation on the watermelon rhizosphere bacterial community diversity and composition in watermelon-wheat intercropping were weaker than those in watermelon monoculture. No contact between wheat and FON was required to decrease the disease index of Fusarium wilt. The effects of wheat intercropping and FON inoculation on the watermelon rhizosphere bacterial community were mostly plant-mediated, and under FON invasion the rhizosphere bacterial community was more stable in watermelon-wheat intercropping than in watermelon monoculture.