A New Biocontrol Agent Bacillus velezensis SF334 against Rubber Tree Fungal Leaf Anthracnose and Its Genome Analysis of Versatile Plant Probiotic Traits

Natural rubber is an important national strategic and industrial raw material. The leaf anthracnose of rubber trees caused by the species is one of the important factors restricting the yields of natural rubber. In this study, we isolated and identified strain SF334, which exhibited significant antagonistic activity against both . and . , the dominant species of causing rubber tree leaf anthracnose in the Hainan province of China, from a pool of 223 bacterial strains. The cell suspensions of SF334 had a significant prevention effect for the leaf anthracnose of rubber trees, with an efficacy of 79.67% against . and 71.8% against . . We demonstrated that SF334 can lead to the lysis of . and . mycelia by causing mycelial expansion, resulting in mycelial rupture and subsequent death. . SF334 also harbors some plant probiotic traits, such as secreting siderophore, protease, cellulase, pectinase, and the auxin of indole-3-acetic acid (IAA), and it has broad-spectrum antifungal activity against some important plant pathogenic fungi. The genome combined with comparative genomic analyses indicated that SF334 possesses most genes of the central metabolic and gene clusters of secondary metabolites in . strains. To our knowledge, this is the first time a strain has been reported as a promising biocontrol agent against the leaf anthracnose of rubber trees caused by . and . . The results suggest that . could be a potential candidate agent for the leaf anthracnose of rubber trees.