Unveiling the Potential of Endophytic Bacillus amyloliquefaciens LJ1 from Nanguo Pear: A Genomic and Functional Study for Biocontrol of Post-Harvest Rot

Bacillus amyloliquefaciens is a well-recognized biocontrol agent and plant growth promoter. This study characterized the endophytic B. amyloliquefaciens LJ1, isolated from Nanguo pear fruit, through whole-genome sequencing and functional analyses. The B. amyloliquefaciens LJ1 genome (3,947,365 bp, 46.48% GC content) encodes 3757 protein-coding sequences. Genomic analysis revealed diverse carbohydrate-active enzymes (CAZymes) and 12 secondary metabolite biosynthetic gene clusters, including those potentially producing surfactin, fengycin, bacillibactin, and bacilysin. Safety assessments, including hemolysis, indole production, biogenic amine production, and a 21 day mice-feeding trial, indicated no adverse effects, suggesting B. amyloliquefaciens LJ1 is non-pathogenic. In vitro assays demonstrated significant inhibitory activity against Penicillium expansum, a major post-harvest pathogen, by suppressing spore germination and germ-tube elongation. These results suggest that B. amyloliquefaciens LJ1 possesses significant biocontrol potential and could be a promising agent for sustainable disease management in Nanguo pear and potentially other crops.