水稻纹枯病生防菌株的筛选、鉴定及其防治效果

为获得对水稻纹枯病有生防潜力的菌株，从湖北省恩施土家族苗族自治州植物根际土壤中分离获得菌株，筛选对水稻纹枯病菌有拮抗作用的菌株，并测定其发酵液的抑菌活性、抑菌谱及生物学特性；基于形态学特征、生理生化特征及分子生物学特征对其进行分类鉴定，并通过离体叶片、室内盆栽和田间试验进一步评价其生防潜力。结果显示，从根际土壤中共分离获得162株菌株，其中生防菌株E12对水稻纹枯病菌的抑制率最高，达94.93%，且该菌株对常见的12种植物病原菌均有抑制作用，抑制率在59.84%~93.14%之间；生防菌株E12能分泌蛋白酶、嗜铁素和淀粉酶，具有固氮及形成生物被膜的能力；结合形态学特征、生理生化特征及分子生物学特征，将菌株E12鉴定为越南伯克霍尔德氏菌Burkholderia vietnamiensis；生防菌株E12处理离体水稻叶片后，其相对病斑长度较对照显著减小，对水稻纹枯病的室内盆栽和田间防治效果分别为62.51%和67.78%。表明越南伯克霍尔德氏菌E12在防控水稻纹枯病方面有较好的潜力。

Screening, identification of biocontrol bacteria and evaluation of its efficacy on rice sheath blight

In order to obtain strains with biocontrol potential against rice sheath blight, strains were isolated from the rhizosphere soil of plants in Enshi Tujia and Miao Autonomous Prefecture, Hubei Province, a strains with antagonistic effects against Rhizoctonia solani were screened, and the antibacterial activity, antibacterial spectrum and biological characteristics of the fermentation broth of the selected strain E12 were determined. Based on the morphological, physiological and biochemical characteristics and molecular biological characteristics, the biocontrol potential was further evaluated by in vitro leaves, indoor pot and field experiments. A total of 162 strains were isolated from rhizosphere soil, among which strain E12 had the highest inhibitory rate against R. solani (94.93%), and its inhibition rates against 12 common plant pathogens ranged from 59.84% to 93.14%. E12 could secrete protease, ferrophilin and amylase, and had nitrogen fixation and biofilm formation ability. Based on the morphological, physiological and biochemical characteristics and molecular biological characteristics, strain E12 was identified as Burkholderia vietnamiensis; after treatment of detached rice leaves with the fermentation broth of E12, the relative spot length was significantly reduced compared with the control, and the control efficacy against rice sheath blight in pot and field experiments was 62.51% and 67.78%, respectively. These results indicated that Bu. vietnamiensis E12 had a good potential for the control of rice sheath blight.