Complete genome structure of the nitrogen-fixing symbiotic bacterium Mesorhizobium loti
Complete genome structure of the nitrogen-fixing symbiotic bacterium Mesorhizobium loti
复制标题
DOI：
10.1093/dnares/7.6.331
复制
发表时间：
2000-12-31
期刊：
影响因子：
4.1
通讯作者：
Tabata, S
中科院分区：
文献类型：
--
作者：
Kaneko, T;Nakamura, Y;Tabata, S
测定了一株共生菌中生根瘤菌MAFF303099的基因组全序列。洛提根结线虫基因组由1条染色体(7,036,071碱基)和两个质粒组成，分别命名为PMLA(351,911碱基)和pMLb(208,315碱基)。该染色体包括6752个潜在的蛋白质编码基因、两组rRNA基因和代表47个tRNA物种的50个tRNA基因。54%的潜在蛋白质基因与已知功能的基因序列相似，21%与假设基因相似，其余25%与已报道的基因没有明显的相似性。确定了一个611kb的DNA片段，这是一个很有可能的共生岛候选基因，并在该区域分配了30个固氮基因和24个结瘤基因。密码子使用分析表明，共生岛和质粒起源于其他遗传系统并传递。PMla和pMLb两个质粒的基因组分别包含320个和209个潜在的蛋白质编码基因，这些基因具有多种生物学功能。这些基因包括与ABC转运蛋白系统、磷酸盐同化、双组分系统、DNA复制和接合有关的基因，但只发现了一个与结瘤有关的基因。
The complete nucleotide sequence of the genome of a symbiotic bacterium Mesorhizobium loti strain MAFF303099 was determined. The genome of M. loti consisted of a single chromosome (7,036, 071 bp) and two plasmids, designated as pMLa (351, 911 bp) and pMLb (208, 315 bp). The chromosome comprises 6752 potential protein-coding genes, two sets of rRNA genes and 50 tRNA genes representing 47 tRNA species. Fifty-four percent of the potential protein genes showed sequence similarity to genes of known function, 21% to hypothetical genes, and the remaining 25% had no apparent similarity to reported genes. A 611-kb DNA segment, a highly probable candidate of a symbiotic island, was identified, and 30 genes for nitrogen fixation and 24 genes for nodulation were assigned in this region. Codon usage analysis suggested that the symbiotic island as well as the plasmids originated and were transmitted from other genetic systems. The genomes of two plasmids, pMLa and pMLb, contained 320 and 209 potential protein-coding genes, respectively, for a variety of biological functions. These include genes for the ABC-transporter system, phosphate assimilation, two-component system, DNA replication and conjugation, but only one gene for nodulation was identified.