苜蓿中华根瘤菌042BMnoeA基因的克隆、敲除与功能的初步分析  

Cloning, deletion and functional analysis of noeA from Sinorhizobium meliloti 042BM

作　　者：杜秉海[1] 姜巨全[1] 李小红[1] 王磊[1] 杨苏声[1] 

机构地区：[1]中国农业大学生物学院微生物学系农业部农业微生物资源与其应用重点开放实验室,北京100094

出　　处：《微生物学报》2005年第2期195-200,共6页Acta Microbiologica Sinica

基　　金：国家"973项目"(2 0 0 1CB10 890 5 );欧盟科技合作项目 (ICA4_CT_2 0 0 1_10 0 5 6)~~

摘　　要：通过PCR扩增获得了 0 4 2BM的noeA基因。该基因与苜蓿中华根瘤菌 (Sinorhizobiummeliloti) 10 2 1noeA的同源性为 99% ,而其NoeA与 10 2 1NoeA的相似性为 97%。还发现其NoeA与中慢生根瘤菌 (Mesorhizobiumsp .)BNC1可能的SAM_依赖性的甲基转移酶相似性为 32 % ,而其 30 3～ 36 2氨基酸区域与大肠杆菌 (Escherichiacoli)的核糖体 5 0S亚基的L11蛋白甲基转移酶 (PrmA)的 16 0～ 2 2 0氨基酸区域的相似性达到 4 1%。通过插入卡那盒 ,敲除noeA ,获得突变株 0 4 2BMA_Km。与苜蓿中华根瘤菌 0 4 2BM相比 ,敲除noeA的突变株在普通紫花、保定、宁夏、百发和傲汉苜蓿品种上的结瘤数、根瘤鲜重和植株地上部分的干重都有不同程度的增加 ,而在秘鲁苜蓿品种上的结瘤数和植株地上部分的干重明显下降 ,在皇后和美国杂花苜蓿品种上则没有明显的变化。BM noeA was obtained by PCR. It is identical to that of S.meliloti 1021 at 99 level, and similarity of their NoeA is 97. In addition, it was found that this protein shares significant homology with the SAM-dependent methyltransferase of Mesorhizobium sp.BNC1(32 similarity), and the similarity of its 303～362 region to the 160～220 region of L11 methyltransferases of E.coli (PrmA) is 41. Compared to 042BM, the noeA deletion mutant 042BMA-Km showed different degrees of increase in number of nodule, fresh weight of nodule and plant top dry weight on alfalfa cultivars of Putong Zihua, Baoding, Ningxia, Baifa and Aohan, but decrease on Milu. However, this mutant has no significant change in ability to nodulate cultivars of Huanghou and Zahua. Hence, noeA is involved in alfalfa cultivar-specific nodulation.

关 键 词：苜蓿中华根瘤菌 结瘤基因 基因敲除 结瘤作用 

分 类 号：Q785[生物学—分子生物学]