华癸中慢生根瘤菌焦磷酸硫胺素结合蛋白基因tpp的功能研究
Function of thiamine pyrophosphate-binding protein gene tpp in Mesorhizobium huakuii

在构建M. huakuii tpp基因突变株的基础上，通过自生生长和植物盆栽试验，研究焦磷酸硫胺素结合蛋白tpp基因在根瘤菌的生长及与紫云英宿主共生固氮过程中的功能。通过同源重组获得华癸中慢生根瘤菌tpp突变菌株HKtpp,并进一步研究tpp基因突变对菌株生长及共生固氮功能的影响。结果显示：tpp基因突变会减缓菌株生长，突变菌株胞内的谷胱甘肽还原酶活性显著降低。植物盆栽试验表明，突变菌株感染紫云英宿主形成有效的红色根瘤，但是其固氮酶活降低了26.4%。结果表明：tpp基因在根瘤菌的生长和共生固氮中发挥着重要作用。
Mesorhizobium huakuii tpp mutant HKtpp was obtained by homologous recombination,and the effects of mutant HKtpp on the growth and symbiotic nitrogen fixation function of the strain were studied by autogenous growth and plant pot experiment. The results showed that the mutant HKtpp reduced the strain growth,and the activity of glutathione reductase in the mutant strain was significantly decreased. The mutant HKtpp formed effective red nodules,but its nitrogenase activity was decreased by 26.4%. It is indicated that tpp gene played an important role in the growth and symbiotic nitrogen fixation of Rhizobium.