百脉根根瘤菌nod-lacZ转录融合子构建及表达分析
Construction and expression study of Mesorhizobium lotinod-lacZ fusions

根据Mesorhizobium loti基因组信息，克隆nodA、nodB、nodD等基因的启动子序列，分别与报告基因构建相应的转录融合子（nod-lacZ），并分别导入中慢生型百脉根根瘤菌MAFF303099和广谱根瘤菌NGR234（Rhizobium sp.）中，利用百脉根根的抽提物作为诱导物，检测结瘤基因的表达。结果表明:在MAFF303099菌株中，百脉根根抽提物不能诱导nodA的表达；能诱导nodB 和nodD1的表达；nodD2呈组成型表达；供试的5种不同的类黄酮化合物都不能诱导nodA基因表达；在NGR234菌株中，毛地黄酮（Luteolin）能诱导nodA表达。
The promoter sequences of nodA,nodB,nodD were cloned based on the genomic information of Mesorhizobium loti MAFF303099 and fused with the reporter gene lacZ to construct the nod-lacZ fusion separately. Then these fusions were separately transformed into M. loti MAFF303099 and Rhizobium sp. NGR234 to detect the expression of these nod genes after induced by Lotus japonicus root extract (RE). The results showed that there was no expression of nodA when treated with root extracts.RE induced expression of nodB and nodD1,but showed upregulation of just 2-3 times. nodD2 expressed constitutively in M. loti MAFF303099.Neither of these induced the expression of nodA in M. loti MAFF303099 induced by 5 different flavonoid compounds separately,but the expression of nodA was detected in NGR234 strain treated by Luteolin.