广西水稻内生细菌的动态分布及其对水稻纹枯病菌的拮抗作用

从广西稻区74种水稻品种中采集了222个水稻标样,分离出1903株内生细菌。经形态和生理生化测定,确定这些菌株分属于芽孢杆菌属Bacillus、鞘胺醇单孢菌属Sphingomonas、土壤杆菌属Agrobacterium、伯克霍尔德氏菌属Burkholderia、肠杆菌属Enterobacter和成团泛菌属Pantoea。其中,Bacillus和Enterobacter为主要类群,Bacillus为优势类群。水稻内生细菌的类群随不同的水稻品种和栽培地区而变化。水稻内生细菌在植株器官中的分布以根部数量最多,其次是叶鞘和叶。内生细菌的总量在水稻生育期的变化趋势是从苗期到孕穗期上升,从灌浆期到乳熟期下降。分离到的1903株内生细菌中,有412个菌株对水稻纹枯病菌Rhizoctoniasolani有拮抗作用。

Dynamic Distribution of Endophytic Bacteria in Rice from Guangxi and Their Antagonism to the Pathogen of Rice Sheath Blight

Study on the distribution and fluctuation of endophytic bacterial population in rice plants is important for screening of specific endophytic bacteria strains to control rice sheath blight.1903 endophytic bacterial strains were isolated from roots,sheaths and leaf tissues of 222 symptomless rice plants collected from Guangxi province.According to the morphological,physiological and biochemical characteristics,these strains were identified as the bacteria in genus of Bacillus,Sphingomonas,Agrobacterium,Burkholderia,Enterobacter and Pantoea.Among them,Bacillus and Enterobacter were the main genus and Bacillus was the dominant genus.The genera of endophytic bacteria in rice were varied with cultivars and cultivating regions.The endophytic bacteria were isolated most frequently in the roots of rice plants,followed by those in sheaths and leaves.The total amount of endophytic bacteria increased gradually from the seedling stage to the booting stage,and then decreased gradually from the filling stage to the milky stage.412 of the 1903 isolates exhibited antagonistic activity against pathogen of rice sheath blight when dual cultured.