Enhanced disease resistance and growth promotion in prickly ash by the rhizobacterium Bacillus velezensis P87

Prickly ash, an economically significant industrial crop valued for its culinary, medicinal, and essential oil applications, is widely cultivated across numerous countries. However, its sustainable production is increasingly threatened by various diseases, with Fusarium solani -induced root rot emerging as one of the most devastating pathogens. The escalating prevalence of root rot, compounded by the lack of effective control measures, underscores the urgent need for sustainable management strategies. This study explored the potential of rhizosphere microorganisms as biocontrol agents against F. solani , with a particular focus on Bacillus species as environmentally friendly alternatives for integrated disease management. Through comprehensive screening and characterization, B. velezensis P87 was identified as the most potent antagonist, exhibiting stable antifungal activity through the production of lipopeptides that effectively inhibit F. solani growth and spore germination. Greenhouse experiments demonstrated that B. velezensis P87 exhibits significant therapeutic and protective efficacy against root rot in prickly ash, with pre-inoculation priming of seedlings resulting in higher control efficiency. Additionally, B. velezensis P87 enhanced chlorophyll content, defensive enzyme activities, and the accumulation of osmolytes (soluble sugars, proteins, and proline) and lignin, thereby promoting plant growth and health. Transcriptomic analysis revealed that B. velezensis P87 priming activated key defense-related pathways, including MAPK signaling, plant hormone signal transduction, and phenylpropanoid biosynthesis, leading to the significant upregulation of defense- and growth-related genes. This study highlights the potential of B. velezensis P87 as an effective biocontrol agent for managing root rot and promoting growth in prickly ash, offering a promising solution for sustainable cultivation practices. • Bacillus velezensis P87 showed potent antifungal activity against Fusarium solani causing root rot in prickly ash. • The antifungal activity of strain P87 was due to lipopeptides, which inhibited fungal growth and spore germination. • Strain P87 effectively controlled root rot and promoted growth, enhancing plant health in prickly ash. • Priming with strain P87 upregulated key genes related to disease resistance and growth in prickly ash.