Deduction of minimum sysmbiosis island gene sets for Lotus rhizobia

为了推导莲与中生根瘤菌共生的最小共生基因组，我们比较了三种中生根瘤菌共生岛的核苷酸序列。loti菌株中发现155个基因是完全保守的。我们制备了可控制的启动子和新的选择标记，用于M。loti菌株。我们还通过突变其rep基因，将广宿主范围载体pBBR 1MCS 2制成温度敏感的衍生物。此外，我们对几种M. loti菌株，并将获得的读段定位在菌株MAFF 303099的基因组序列上。这一结果支持M.共生岛核心结构保守的loti菌株。

In an attempt to deduce the rhizobial minimum symbiosis gene sets for mutualism between Mesorhizobium loti and Lotus species, we compared nucleotide sequences of symbiosis islands of three M. loti strains and found 155 genes are completely conserved among them. We made controllable promoters and new selectable markers to be used with M. loti strains. We also made a temperature sensitive derivative of the broad-host range vector pBBR1MCS2, by mutagenesis of its rep gene. In addition, we performed Next Generation Sequencing analysis of several M. loti strains and mapped the obtained reads on the genome sequence of the strain MAFF303099. The results supported the divergence of main chromosomes among M. loti strains with conserved core structure of symbiosis island.