一株沙福芽胞杆菌ZG6的筛选、鉴定及其对茶树轮斑病的生防潜力研究

轮斑病是茶树生产上的重要病害，造成茶叶产量和品质重大损失。为获得有效防治茶树轮斑病的生防菌株，从合肥茶园茶树根部组织中分离筛选到一株对茶树轮斑病菌具有较强拮抗活性的内生细菌ZG6。对峙培养条件下，该菌株对茶树轮斑病菌的菌丝抑制率可达65.38%。基于菌落形态、生理生化特征、16S r RNA和gyr B基因的序列分析，将菌株ZG6鉴定为沙福芽胞杆菌Bacillussafensis。菌株ZG6具有广谱抑菌能力，对油菜菌核病菌、玉米小斑病菌和苹果腐烂病菌表现出较强的抑制效果，抑制率分别为78.82%、64.71%和61.82%。酶学试验结果表明，菌株ZG6在代谢过程中可产生纤维素酶和蛋白酶。茶树离体枝条叶片防效试验结果表明，菌株ZG6的发酵液、无菌发酵滤液与菌液均对茶树轮斑病有预防和控制效果，在茶树离体枝条的叶片上的防效可达69.9%以上。由此可见，沙福芽胞杆菌ZG6具有作为防治茶树轮斑病生防菌剂研发的潜力。

Screening and Identification of Bacillus safensis ZG6 and Its Biocontrol Potential against Gray Blight on Camellia sinensis

Tea gray blight is a severe disease that occurred in tea plantings in China, causing significant losses to tea yield and quality. In order to obtain effective biocontrol strains against tea gray blight, an endophytic bacterium ZG6 with strong antagonistic activity against the pathogen Pseudopestalotiopsis sp. DSP-6 was isolated and screened from tea roots in Hefei. The strain ZG6 inhibited mycelial growth by dual culture assay, with an inhibition rate of 65.38%. Based on colony morphology, physiological and biochemical characteristics, partial nucleotide sequences of 16S rRNA and gyrB gene, strain ZG6 was identified as Bacillus safensis. The strain ZG6 had a broad-spectrum inhibition ability against Sclerotinia sclerotiorum, Bipolaris maydis, and Cytospora mandshurica, with inhibition rates of 78.82%, 64.71% and 61.82%, respectively. The enzymatic test revealed that strain ZG6 produced cellulase and protease in the metabolic process. The fermentation broth, fermentation filtrate and suspension of strain ZG6 showed control efficacy over 69.9% against gray blight on the leaf of the tea detached branch. In summary, B. safensis ZG6 could be a potential biocontrol agent for the management of tea gray blight.