枸杞炭疽病生防菌株筛选、生物功能测定及防治效果

为研发对枸杞炭疽病有良好防治效果的生防制剂，利用枸杞炭疽病菌Colletotrichum acutatum对实验室已分离保存的芽胞杆菌菌株进行室内筛选，并对拮抗效果较好的菌株进行形态学和分子生物学鉴定、病原菌孢子萌发抑制试验、生物学功能测定、稳定性测定、抑菌谱测定以及室内离体防治效果试验和田间防治效果试验。结果表明，菌株F3A对枸杞炭疽病菌有较好的拮抗作用，对枸杞炭疽病菌菌丝的抑制率为62.13%；结合形态学特征、16S rDNA以及gyrA基因序列分析，将菌株F3A鉴定为贝莱斯芽胞杆菌Bacillus velezensis；菌株F3A具有溶解有机磷和无机磷的能力，在含色氨酸和不含色氨酸的金氏培养液中产吲哚乙酸量分别为5.76 mg/L和5.74 mg/L；菌株F3A产蛋白酶和葡聚糖酶的活性较高；菌株F3A连续培养20代后，对枸杞炭疽病菌的抑制率为61.21%，该菌对棉花枯萎病菌Fusarium oxysporum f.sp.vesinfectum、番茄早疫病菌Alternaria solani、黄瓜枯萎病菌F.oxysporum f.sp.cucumerinum、番茄灰霉病菌Botrytis cinerea、番茄叶霉病菌Cladosporium fulvum、茄子菌核病菌Sclerotinia sclerotiorum和黄芪根腐病菌F.solani的抑制率分别为40.71%、53.58%、32.00%、53.00%、79.27%、71.13%和66.08%；菌株F3A发酵液的保护作用明显优于治疗作用，菌株F3A发酵液1倍稀释液室内预防效果为90.32%；喷施菌株F3A发酵液1倍稀释液3 d和7 d后的田间防治效果分别为78.26%和63.19%。表明菌株F3A有作为开发枸杞炭疽病生物农药的潜力。

Screening of biocontrol bacteria against Chinese wolfberry anthracnose, determination of its biological functions and biocontrol efficacy

In order to develop biocontrol agents with good prevention and control efficacy against wolfberry anthracnose, Colletotrichum acutatum was used to screen Bacillus strains isolated and preserved in our laboratory. The morphological and molecular biological identification, pathogen spore germination inhibition test, biological function test, stability test, inhibition spectrum test, laboratory in vitro control and field control effect test of the Bacillus strains with higher fungicidal activity were carried out. The results showed that the strain F3A had strong antagonistic ability against Chinese wolfberry anthracnose, with an inhibition rate of 62.13%. The strain was identified as Bacillus velezensis based on morphological observation, 16S rDNA and gyrA gene sequence analysis. The strain F3A was able to dissolve organic phosphorus and inorganic phosphorus and the secreted contents of indole-3-acetic acid were 5.76 mg/L and 5.74 mg/L on the King media with 100 mg/L tryptophan and without tryptophan, respectively. The strain F3A had a higher activity of protease and glucanase and its growth inhibition rate was 61.21% after continuous culture for 20 generations. The inhibition spectrum tests showed that the inhibition rates of the F3A strain against Fusarium oxysporum f. sp. vesinfectum, Alternaria solani, F. oxysporum f. sp. cucumerinum, Botrytis cinerea, Cladosporium fulvum, Sclerotinia sclerotiorum and F. solani were 40.71%, 53.58%, 32.00%, 53.00%, 79.27%, 71.13% and 66.08%, respectively. The protective effect of strain F3A fermentation broth was better than that of control, the protective effect of 1×diluent of fermentation broth was 90.32%. The field control test results confirmed that the prevention effect of strain F3A three days and seven days after spray were 78.26% and 63.19%, respectively. The results suggested that strain F3A had the potential to be used as a biological pesticide for the control of Chinese wolfberry anthracnose.