gusA基因检测慢生花生根瘤菌竞争性的研究

采用大肠杆菌和根瘤菌接合的方法,将gusA标记基因分别导入了2株慢生型花生根瘤菌Spr3-5和Spr4-5中。结果表明,gusA基因在2株慢生型花生根瘤菌Spr3-5和Spr4-5中可以有效表达;对出发菌株和标记菌株的代时测定结果表明,二者之间没有显著差异;在标记菌株与出发菌株等量接种的前提下,比较了二者的竞争结瘤能力,结果表明,标记菌株形成的根瘤(蓝瘤)的占瘤率与出发菌株差异不显著;为了研究标记菌株与出发菌株的固氮有效性,测定了标记菌株与出发菌株各自共生植株的干重、全氮和叶绿素含量,结果表明,标记菌株与出发菌株的这3项指标之间没有显著差异。这说明利用gusA基因研究慢生根瘤菌的竞争结瘤能力是可行的。

Study on the Competitiveness of Peanut Bradyrhizobial Strains Using gusA

The gusA gene was introduced into 2 peanut bradyrhizobiol strains, Spr3-5 and Spr4-5 respectively by conjugation. The result showed that the gusA gene in Spr3-5 and Spr4-5 could be expressed effectively. The detectiong of generation time of marked and parental strains demonstrated there was no significant difference between them, which indicated their growth rate was the same. Inoculating parental and marked strains at 1:1 ratio, their competitive ability was tested. The result showed that the proportion of blue nodules didn't differ significantly from 50 %. It indicated that the competitiveness of maked strains was not changed significantly compared with the parent strains. To study nitrogen fixing efficiency of marked and parental strains, the symbiotic shoot dry weight, the contents of total nitrogen and chlorophyll of marked and parental strains were tested. The result showed that there was no significant difference between them, which indicated that the nitrogen fixing efficiency of marked strains didn't differ from parental strains markedly in different ways. It was proved that the application of gusA in competitiveness study of Bradyrhizobium sp.(arachis) was simple and reliable.