CAJ | 학술논문

苜蓿中华根瘤菌nifA基因在共生固氮过程中担负着调控功能,nifA突变株Rm1354在宿主植物的根部诱导白色无效根瘤.本文报道Rm1354在自生状态下的表型变化.nifA的突变导致根瘤菌在半固体培养基上泳动变慢,胞外蛋白含量降低.有趣的是,Rm1354在延宕期间高丝氨酸内酯含量比野生型低,在指数期和静止期却比野生型高.另外,突变株Rm1354的竞争结瘤能力也大大减弱.这些结果揭示了苜蓿中华根瘤菌nifA基因对许多细胞学过程都有调控作用.
목숙중화근류균nifA기인재공생고담과정중담부착조공공능,nifA돌변주Rm1354재숙주식물적근부유도백색무효근류.본문보도Rm1354재자생상태하적표형변화.nifA적돌변도치근류균재반고체배양기상영동변만,포외단백함량강저.유취적시,Rm1354재연탕기간고사안산내지함량비야생형저,재지수기화정지기각비야생형고.령외,돌변주Rm1354적경쟁결류능력야대대감약.저사결과게시료목숙중화근류균nifA기인대허다세포학과정도유조공작용.
Sinorhizobium meliloti nifA is important in fixing nitrogen during symbiosis. A nifA null mutant induces small white invalid nodules in the roots of host plant. The additional phenotypic alterations associated with the disruption of the nifA gene are reported in this study. Under a free-living state, S. meliloti nifA mutant reduces its ability to swarm on a half-solid plate. Interestingly, the AHL (Acylhomoserine lactones) contents in the nifA mutant are lower than that of the wild type during the lag phase,whereas it is reversed in the logarithmic and stationary phases. Quantitative spectrophotometric assays reveal that the total amount of extracellular proteins of the nifA mutant are lower than that of the wild type. In addition, the mutant abolishes its nodulation competitive ability during symbiosis. These findings indicate that NifA plays a regulatory role in multiple cellular processes in S.meliloti.