生防菌株336x 在小麦内部的定殖研究

摘要

变形斑沙雷氏菌（Serratia p roteamaculans ）336x是一株对小麦全蚀病具有生防作用的小麦内生细菌。为研究336 x在小麦内部的定殖及分布，将336 x基因组酶切片段与携带绿色荧光蛋白基因（g f p）的质粒pAD123进行连接，筛选产生荧光的质粒并转化336x菌株，获得336x的荧光标记菌株336x gfpa。对比336x gfpa与野生型菌株在小麦中的定殖能力及对小麦全蚀病的生防能力，发现二者无显著差异；荧光显微镜观察结果表明，336x gfpa主要定殖于小麦根部细胞间隙和维管组织。%Serratia proteamaculans strain 336x isolated from wheat roots is an endophytic bacte-rium and has biological control activity against take-all of wheat induced by Gaeumannomyces graminis var .tritici .To elucidate colonization pattern of 336x in wheat ,the genomic DNA frag-ments of 336x were inserted into pAD123 to construct pAD123-336x ,in which the gf p gene was expressed under the control of 336x gene promoter .The plasmid pAD123-336x was transferred in-to 336x wild type strain by electroporation ,and one mutant designated as 336x-gfpa was acquired . Colonization study and biocontrol assay revealed that 336x-gfpa had comparatively equal biocon-trol activity and colonization ability to 336x .Observation under fluorescent microscope revealed that 336x-gfpa was mainly colonized in intercellular space and vascular tissue of wheat root .