应用全细胞蛋白SDS-PAGE分子标记技术验证含羞草根瘤菌的结瘤能力

对云南省热带及亚热带地区的含羞草根瘤菌进行了分离,选择其中40株菌为接种菌株,通过结瘤试验并采用全细胞蛋白SDS-PAGE分子标记方法研究了其结瘤能力.经过结瘤试验,发现除菌株SWF66075和SWF66093没有结瘤外,其它38株菌株均与含羞草植物结瘤.结瘤率为95%.从结瘤试验所获根瘤中,分离得到结瘤菌株,采用全细胞蛋白SDS-PAGE分子标记对结瘤菌株与接种菌株进行了比较研究.蛋白图谱及聚类分析显示,26株接种菌株与其结瘤菌株的全细胞蛋白分子图谱完全相同,在100%的相似水平上与其结瘤菌株聚在一起,说明宿主植物所形成的根瘤确系接种菌株侵入所致,因而可将这些菌株确认为根瘤菌菌株;而SWF66012、SWF66029、SWF66044和SWF66058等12株菌株的结瘤菌株与其各自接种菌株的全细胞蛋白图谱存在较大差异,推测这12株接种菌株与其结瘤菌株可能不是同一菌株,尚不能确定它们与含羞草植物的结瘤能力,这些菌株是否为根瘤菌菌株仍需进一步验证.研究结果表明,全细胞蛋向SDS-PAGE分子标记技术是一种快速、准确地验证根瘤菌结瘤能力的方法.该方法进一步完善了结瘤试验,并初步揭示了根瘤菌的竞争结瘤能力,适用于对大量根瘤内分离菌株进行根瘤菌的证实研究.图2参28

Verification of Nodulation Ability of Strains Isolated from Mimosa spp. Nodules Using Whole Cell Protein SDS-PAGE Molecular Marker Method

The nodules of Mimosa spp. were collected from some areas in Yuanjiang and Xishuangbanna, Yunnan, China. Bacteria were isolated from these nodules with modified medium, and 40 strains were selected to carry out the nodulation test. The result showed that 38 strains could nodulate M. pudica. The nodulation rate was approximately 95%. 38 re-isolated strains and their whole cell protein profiles were obtained. The clustering analysis demonstrated that 26 re-isolated strains had a protein pattern identical to that of their original strains at the similarity of 100%, indicating that these 26 strains could establish symbiosis with M. pudica. The whole cell protein profiles of 12 strains were different from those of the re-isolated strains, indicating that the nodules were not formed by them and further research is needed. This study shows that the whole cell protein SDS-PAGE can be used in inoculation test, and it is a time-saving and accurate molecular marker to identify rhizobia, especially for characterizing plenty of isolates from nodules of various plants. Also, this study preliminarily reveals that the competitive nodulation ability differs among rhizobiai strains. Fig 2, Ref 28