洪湖市土壤中快生型大豆根瘤菌的多样性

DIVERSITY OF RHIZOBIUM FREDII STRAINS IN THE SOIL OF HONGHU COUNTY

从湖北省洪湖市土壤中分离纯化了９２株快生型大豆根瘤菌。用来自８个取样地点的１２个快生型典型菌株和１个慢生型菌株的抗血清检测了该快生型大豆根瘤菌群体的抗原构成。其中６５株菌归入１５个血清型，２０．７％属于ＵＳＤＡ２０５型，１５．２％为Ａｄ３０１（１）型。有２７株不与已知抗血清反应，为未知的血清型。对供试菌株质粒进行的快速检测结果表明，各菌株均含有２～６个质粒，其中最大的质粒在５００Ｍｄ左右。含４个质粒的菌株最多，含５～６个质粒的菌株较少。根据质粒图谱分析，洪湖快生型大豆根瘤菌可分为１１个质粒型．菌株的质粒型与血清型之间无明显相关性。

Rhizobial strains were isolated from soybean (Glycine max ) cultivar Aijiaozao grown in the soil in Honghu County Hubei Province, under soybean cultivation without inoculation for decades. Every nodule on the sampled roots was collected to make isolation instead of selection at random. After purification and authentication,a total of 92 Rhizobium fredii strains were obtained. Each strain was tested with polyclonal antisera produced against 1 2 Rhizobium fredii and 1 Bradyrhizobium japonicum strains by agglutination reaction in tube, 65 strains fell into 1 5 serogroups and the remainding 27 strains showed no reaction to the antisera used. The plasmid profiles of these strains were determined by modified procedure of Eckhardt rapid visualization. All of the strains contained 2～6 plasmids. The size of these plasmids ranged from approximately 12 Md to 530 Md with strain USDA205 as reference. The strains tested could be classified into 11 plasmid groups. The results showed that the diversity occurred not only in strains from different host plants but also in those from single host plant.