根癌农杆菌中DapB突变株功能的研究  

Characterization of the DapB mutant of Agrobacterium tumefaciens

作　　者：阎春兰[1] 赵薇 陈凤美 王祖英 谭彦平 YAN Chunlan;ZHAO Wei;CHEN Fengmei;WANG Zuying;TAN Yanping(College of Life Sciences,South-Central Minzu University,Wuhan 430074,China)

机构地区：[1]中南民族大学生命科学学院,武汉430074

出　　处：《中南民族大学学报（自然科学版）》2023年第5期600-608,共9页Journal of South-Central University for Nationalities：Natural Science Edition

基　　金：国家自然科学基金资助项目(31772399);国家级大学生创新创业训练计划(202010524016)。

摘　　要：在对根癌农杆菌中二氢吡啶二羧酸还原酶DapB蛋白序列分析的基础上,利用转座子诱变敲除dapB基因.结果发现,根癌农杆菌中的DapB序列具有典型的保守的二核苷酸结合域和底物结合域.dapB基因突变后,突变株的生长明显延迟,外加二氨基庚二酸可恢复突变株的生长;突变株可能通过在细胞膜中合成更多的蛋白质和提高细胞壁碳水化合物含量来提高细胞的韧性以对抗外界环境;与此同时,dapB基因突变影响到农杆菌对GABA的响应.以上结果说明根癌农杆菌中DapB蛋白是一个有功能活性的二氢吡啶二羧酸还原酶,与细胞的生长、细胞壁的合成以及细胞对GABA的响应有关.本研究为寻求新的抗生素靶位点以控制根癌农杆菌中冠瘿瘤奠定了基础.Based on the amino acid sequence analysis of DapB protein(dihydrodipicolinate reductase)in Agrobacterium tumefaciens(A.tumefaciens),the dapB gene of A.tumefaciens was knocked out by transposon T5 mutation to obtain mutant and complementary strains.Compared with DapB proteins in other microorgranisms,the amino acid sequences of the agrobacterial DapB protein had the typical conserved dinucleotide binding domain and substrate binding domain.When the dapB gene was mutated by Tn5 transposon in A.tumefaciens,the growth of mutant was obviously delayed.The detention growth of mutant could restore to the level of WT by adding diaminopimelate(DAP),not by lysine.The mutant might increase the tenacity by synthesizing more protein in the membrane and enhancing the carbohydrate content in cell wall to counteract the external environment.Meanwhile,the dapB mutation influenced A.tumefaciens to response GABA.The above results showed that the DapB protein in A.tumefaciens is a functional homolog of dihydrodipicolinate reductase and directly related with the growth of cells,cell wall synthesis and cells response to GABA.This study is useful to characterize novel antibiotic target for biological control of crown gall disease caused by A.tumefaciens.

关 键 词：根癌农杆菌 二氢吡啶二羧酸还原酶 抗生素靶位点 植物病原菌 

分 类 号：Q93[生物学—微生物学]