Isolation and Identification of Biocontrol Bacteria against Root Rot and Their Effects.

Fusarium root rot (FRR) seriously affects the growth and productivity of . Therefore, protecting from FRR has become an important task, especially for increasing production. The purpose of this study was to screen FRR control strains from the rhizosphere soil. Eighty-four bacterial strains and seven fungal strains were isolated, and five strains were identified with high inhibitory effects against (FO): (MH), (CJ5, CJ7, and CJ8), and (CJ9). All five strains had high antagonistic effects in vitro. Results showed that MH and CJ5, as biological control agents, had high control potential, with antagonistic rates of 86.01% and 82.78%, respectively. In the pot experiment, the growth levels of roots and stems of seedlings treated with MH+CJ were significantly higher than those of control plants. The total nitrogen, total phosphorus, total potassium, indoleacetic acid, and chlorophyll contents in leaves were also significantly increased. In the biocontrol test, the combined MH + CJ application significantly decreased the malondialdehyde content in roots and significantly increased the polyphenol oxidase, phenylalanine ammonolyase, and peroxidase ability, indicating a high biocontrol effect. In addition, the application of spp. and increased the abundance and diversity of the soil fungal population, improved the soil microbial community structure, and significantly increased the abundance of beneficial strains, such as and . The abundance of , , and other pathogenic strains was significantly reduced, and the biocontrol potential of root rot was increased. Thus, spp. and complex bacteria can be considered potential future biocontrol agents for FRR.