关键词: 贝莱斯芽孢杆菌, 中药材, 怀山药, 怀地黄, 怀牛膝, 促生作用, 生物防治, 全基因组测序

Abstract: To evaluate the biocontrol and growth‑promoting effects of Bacillus velezensis Bv1‑4 on three medicinal plants（Dioscorea opposite Thunb.，Rehmannia glutinosa Libosch.，Achyranthes bidentata Blume.）and elucidate its mechanisms，the antagonistic effects against different pathogens were assessed through plate confrontation assays and fermentation filtrate antibacterial tests，and the control efficacy was validated through indoor pot trials. Whole‑genome sequencing of strain Bv1‑4 was conducted using third‑generation sequencing technology，and genomic characteristics were analyzed to identify functional genes and assess secondary metabolite biosynthesis potential，thereby further elucidating its antagonistic mechanisms.The results showed that antibacterial rates of isolate Bv1‑4 against Fusarium solani F.oxysporum and F.proliferatum were 67.12%，54.20% and 67.97%，respectively.Both fermented filtrate and sterilized fermented filtrate inhibited mycelial growth and spore germination.In pot experiments，the biocontrol efficacy of isolate Bv1‑4（45.39%—62.31%）was comparable to that of the 500‑fold dilution of 10% difenoconazole water‑dispersible granule. And sole inoculation with isolate Bv1‑4 significantly increased root fresh weight of D.opposite，R.glutinosa，A.bidentata by 19.30%，36.66%，and 75.36%，respectively.Whole genome sequencing revealed that the genome of isolate Bv1‑4 was circular with a length of 4 075 292 bp and the G+C content of 46.35%，and had 4 030 protein‑coding genes.antiSMASH analysis predicted 14 secondary metabolite biosynthetic gene clusters in the genome of isolate Bv1‑4，including seven with complete（100%）similarity to clusters encoding amyloliquecidin GF610，macrolactin H，bacillaene，fengycin，difficidin，bacillibactin，and bacilysin.In conclusion，B.velezensis Bv1‑4 demonstrates excellent biocontrol efficacy against Fusarium diseases in medicinal plants，along with significant plant growth‑promoting traits. These findings highlight its potential for development as a specialized microbial agent for traditional Chinese medicinal crops.

Key words: Bacillus velezensis；Chinese medicinal plant；Dioscorea opposite Thunb.；Rehmannia , glutinosa Libosch.； Achyranthes bidentata Blume.；Growth?promoting effect；Biocontrol；Whole genome sequencing