期刊
JOURNAL OF BACTERIOLOGY
卷 183, 期 8, 页码 2595-2604出版社
AMER SOC MICROBIOLOGY
DOI: 10.1128/JB.183.8.2595-2604.2001
关键词
-
类别
Inositol derivative compounds provide a nutrient source for soil bacteria that possess the ability to degrade such compounds. Rhizobium strains that are capable of utilizing certain inositol derivatives are better colonizers of their host plants. We have cloned and determined the nucleotide sequence of the myo-inositol dehydrogenase gene (idhA) of Sinorhizobium fredii USDA191, the first enzyme responsible for inositol catabolism. The deduced IdhA protein has a molecular mass of 34,648 Da and shows significant sequence similarity with protein sequences of Sinorhizobium meliloti IdhA and MocA; Bacillus subtilis IolG, YrbE, and YucG; and Streptomyces griseus StrI. S. fredii USDA191 idhA mutants revealed no detectable myo-inositol dehydrogenase activity and failed to grow on myo-inositol as a sole carbon source. Northern blot analysis and idhA-lacZ fusion expression studies indicate that idhA is inducible by myo-inositol. S, fredii USDA191 idhA mutant was drastically affected in its ability to reduce nitrogen and revealed deteriorating bacteroids inside the nodules. The number of bacteria recovered from such nodules was about threefold lower than the number of bacteria isolated from nodules initiated by S. fredii USDA191. In addition, the idhA mutant was also severely affected in its ability to compete with the wild-type strain in nodulating soybean. Under competitive conditions, nodules induced on soybean roots were predominantly occupied by the parent strain, even when the idhA mutant was applied at a 10-fold numerical advantage. Thus, we conclude that a functional idhA gene is required for efficient nitrogen fixation and for competitive nodulation of soybeans by S. fredii USDA191.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据