植物保护学报2025，Vol.52Issue(6)：1404-1415,12.DOI:10.13802/j.cnki.zwbhxb.2025.2025076
烟草棒孢霉叶斑病生防菌GK-6的抗病机制
The mechanism of resistance in biocontrol bacterial strain GK-6 against tobacco Corynespora leaf spot
摘要
Abstract
In order to screen for biocontrol bacterial sources against tobacco Corynespora leaf spot,endophytic bacteria have been isolated from healthy tobacco in the disease-affected tobacco-growing areas in Zunyi City,Guizhou Province.Then the antagonistic strain was screened using the fungal patho-gen Corynespora cassiicola,and identified by combining colony morphology characteristics with multi-locus sequence analysis.Its biofilm-forming ability and swarming motility were analyzed using crystal violet staining and plate motility assays.Subsequently,the pot experiment was conducted to evaluate the control efficacy of the antagonistic strain against the tobacco Corynespora leaf spot.Furthermore,conidial germination inhibition assays,mycelial growth rate determination,and Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry analysis were performed to elucidate the anti-fungal mechanisms of this antagonistic strain.Subsequently green fluorescent protein labeling was employed to investigate the colonization dynamics of this antagonistic strain in tobacco plants.The results demonstrated that a bacterial strain,which exhibited an inhibition rate of 63.75%to Corynespora cassiicola,has been obtained and named GK-6.The strain GK-6 was identified as Bacillus velezensis,exhibiting strong biofilm-forming capacity and swarming motility.Its control efficacy on Corynespora leaf spot in tobacco reached 41.67%.The conidial germination of C.cassiicola treated with the fermen-tation supernatant of the strain GK-6 for 96 h was only 64.67%,which was lower than that of the con-trol group(100.00%).The crude extract of the strain GK-6 exhibited potent antifungal activity against C.cassiicola with an EC50 value of 0.032 mg/mL,and the crude extract contained antimicrobial com-pounds such as fengycin,surfactin,and bacillomycin.Additionally,the strain GK-6 could stably colo-nize on the leaves of tobacco plants,on the 35th day after inoculation,its population was 2.87×103 CFU/g.The results of this study provided a theoretical basis for the development of B.velezensis GK-6 as a bio-control agent.关键词
烟草棒孢霉叶斑病/多主棒孢霉/贝莱斯芽胞杆菌/脂肽/分生孢子萌发Key words
tobacco Corynespora leaf spot/Corynespora cassiicola/Bacillus velezensis/lipopeptide/conidial germination引用本文复制引用
于心如,李琳新,吴惠平,张婷婷,谈发洋,夏春成,黄纯杨,丁婷..烟草棒孢霉叶斑病生防菌GK-6的抗病机制[J].植物保护学报,2025,52(6):1404-1415,12.基金项目
贵州省烟草公司遵义市公司科技项目(2022XM09),中国烟草总公司重点研发项目(110202202014) （2022XM09）
