快生型大豆根瘤菌（Rhizobium　fredii）3．7Kb增效片段的亚克  

Cloning and Sequencing of a 3. 7kb Enhancing Fragment from Rhizobium friedii B52

作　　者：张学贤[1] 马立新[1] 周俊初[1] 陈华癸 

机构地区：[1]华中农业大学微生物系

出　　处：《高技术通讯》1996年第4期4-7,共4页Chinese High Technology Letters

基　　金：863计划资助

摘　　要：利用柯氏质粒ｐＬＡＦＲ１为载体构建了快生型大豆根瘤菌Ｂ５２菌株的基因文库，并通过植物结瘤试验筛选到一个３．７Ｋｂ增效片段，将其导入慢生型大豆根瘤菌２２１０，能提高其共生固氮效率。所得高效菌株ＨＮ３２在黑龙江、四川和广西大面积应用，平均增产１１．４％（５）。本文测定了３．７Ｋｂ片段的核苷酸序列，计算机分析发现含有两个开放阅读框架（ＯＲＦｓ）。ＯＲＦ１编码含１９０个氨基酸的多肽，与已报道基因和多肽的同源性很低，但其Ｎ端１９个氨基酸与发根农杆菌的乳糖转移酶高度同源。ＯＲＦ２编码含２３５个氨基酸的多肽，与碗豆根瘤菌的ｈｕｐＥ及苜蓿根瘤菌的糖基转移酶基因显示５４％的同源性。The cosmid gene library of Rhizobium fredii strain B52 genome was constructed, and a 3. 7kb enhancing fragment was isolated through plant experiment, which could improve the symbiotic efficiency of Bradyrhizobium strain 2210. The obtained highly effective strain was called HN32. It has been widely used as soybean inoculant in Helongjiang, Sichuan and Guangxi provinces with an average of 6% yield increase comparing with 2210. The recombinant plasmid pHN32 in strain HN32 contains a 3. 7kb foreign insert (Zhou et al. 1990). Its nucleotide seuqence was analyzed. Computer analysis indicated that there were two open reading frames (ORFs) within the 3. 7kb enhancing fragment. ORF1 shows no homology with known genes except the first 19 amino acids which had high homology with lactose transferase of Agrobacterium trdiobacter. ORF2 shows 54% homology with hupE of Rhizobium leguminosarum,and related with glycosylation transfer gene of Rhizobium meliloti. Names enfA and enfB are proposed to ORF1 and ORF2 respectively.

关 键 词：大豆 根瘤菌 亚克隆 序列分析 

分 类 号：S565.1[农业科学—作物学]