Intercropping of wheat changed cucumber rhizosphere bacterial community composition and inhibited cucumber Fusarium wilt disease

Abstract

Enhancing the plant rhizosphere microbial community function by increasing plant diversity in the field is a promising strategy for enhancing agricultural sustainability. This study evaluated the effectiveness of the intercropping of wheat in controlling cucumber Fusarium wilt disease. Bacterial community diversity and abundance in cucumber rhizosphere were estimated by high-throughput amplicon sequencing and quantitative polymerase chain reaction (PCR). Results showed that the intercropping of wheat inhibited the severity of cucumber seedling Fusarium wilt disease, increased the alpha diversity and altered the composition of the bacterial community in cucumber rhizosphere. Compared with monocropped cucumber, intercropped cucumber had higher relative abundances of Anaerolineae, Deltaproteobacteria, Phycisphaerae and Planctomycetacia, and lower Alphaproteobacteria and Cyanobacteria. Moreover, the intercropping of wheat promoted bacterial genera with plant-beneficial potential (e.g. Pseudomonas, Haliangium and Archangium spp.) in cucumber rhizosphere. Quantitative PCR confirmed that Pseudomonas spp. abundance was higher in intercropped cucumber rhizosphere than in monocropped cucumber rhizosphere. Overall, the intercropping of wheat decreased the severity of Fusarium wilt of cucumber and promoted potential plant-beneficial microbes in cucumber rhizosphere.