Sinorhizobium meliloti nifA gene exerts a pleiotropic effect on nodulation through the enhanced plant defense response  

作　　者：CHEN XiaoTao ZOU HuaSong YAO ZhenHua CHENG HaiPing DAI XiaoMi ZHU JiaBi YU GuanQiao 

机构地区：[1]National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100039, China [3]Biological Sciences Department, Lehman College, the City University of New York, Bronx, New York 10468, USA

出　　处：《Chinese Science Bulletin》2007年第21期2925-2929,共5页

基　　金：Supported by the National Basic Research Program of China (Grant No. 2001CB108901);National Natural Science Foundation of China (Grant No. 30170512)

摘　　要：Sinorhizobium meliloti nifA gene is required for the expression of a bunch of nif and fix genes. Here, we report its pleiotropic effects on the nodule formation. Compared with wild type strain, nifA mutant sig- nificantly reduced nodule suppression rate in split-root system. The plants inoculated with mutant strain produced lower amount of daidzein and less necrotic cells on their roots. In addition, the defense genes failed to be evoked by nifA mutant at the early nodulation stage. These findings indicated that host defense response was one of the mechanisms mediated by nifA gene to regulate nodule formation during symbiosis. Even though nifA mutant could increase the number of nodules in host plant, it synthesized lower Nod factors than wild type. This suggested that nifA gene mediated multiple and diverse instances in nodulation formation.Sinorhizobium meliloti nifA gene is required for the expression of a bunch of nif and fix genes. Here, we report its pleiotropic effects on the nodule formation. Compared with wild type strain, nifA mutant significantly reduced nodule suppression rate in split-root system. The plants inoculated with mutant strain produced lower amount of daidzein and less necrotic cells on their roots. In addition, the defense genes failed to be evoked by nifA mutant at the early nodulaUon stage. These findings indicated that host defense response was one of the mechanisms mediated by nifA gene to regulate nodule formation during symbiosis. Even though nifA mutant could increase the number of nodules in host plant, it synthesized lower Nod factors than wild type. This suggested that nifA gene mediated multiple and diverse instances in nodulation formation.

关 键 词：多效性反应 结瘤 植物 防御能力 

分 类 号：Q94[生物学—植物学]