四川地区结瘤大豆根际土壤中紫云英、苜蓿和三叶草根瘤菌的多样性分析  

Diversity of rhizobia nodulating Astragalus sinicus, Medicago sativa and Trifolium repens in nodulated soybean rhizosphere soil in Sichuan

作　　者：李艳梅[1] 钟宇舟 谭渊[1] 何中山[1] 徐雯芳 陈强[1] 余秀梅[1] 

机构地区：[1]四川农业大学资源环境学院微生物系,成都610041

出　　处：《应用与环境生物学报》2015年第2期234-241,共8页Chinese Journal of Applied and Environmental Biology

基　　金：教育部博士点基金项目(20135103120003);国家自然科学基金项目(31300461);四川农业大学"人才引进项目";四川农业大学大学生创新性实验计划项目和科研兴趣计划项目资助~~

摘　　要：为了解四川地区结瘤大豆根际土壤是否存在与紫云英、苜蓿和三叶草共生结瘤的根瘤菌及其多样性,从四川盆地采集不同种植模式下结瘤大豆根际土壤样品31份,利用紫云英、苜蓿和三叶草进行盆栽捕获试验以获得共生根瘤,从根瘤中分离纯化出根瘤菌,对其进行表型和分子鉴定;并将根瘤菌回接到紫云英、苜蓿、三叶草和大豆根际以检测根瘤菌的寄主范围.在捕获实验中,苜蓿和三叶草分别在6个土壤样品中共生结瘤,而紫云英只在2个土样中共生结瘤,并从共生根瘤中分离出14株根瘤菌;16S r DNA基因序列的相似性分析表明这14株根瘤菌均属于根瘤菌属(Rhizobium),且16S r DNA基因的系统发育树揭示它们分属于根瘤菌属的不同种;这14株根瘤菌在回接实验中都只能让捕获豆科植物结瘤,而不能让其他3种豆科植物结瘤.本研究结果表明,四川地区结瘤大豆根际土壤中的紫云英根瘤菌(Rhizobium astragali)、苜蓿根瘤菌(R.meliloti)和三叶草根瘤菌(R.leguminosarum var.trifolii)资源较少,其与大豆根瘤菌(Bradyrhizobium japonicum)分属于不同的属,且根瘤菌的回接实验进一步证明了根瘤菌的寄主专一性.This study collected thirty-one rhizosphere soil samples of nodulated soybean with different planting styles fromthe Sichuan Basin to analyze whether rhizobia nodulating with Astragalus sinicus, Medicago sativa and Trifolium repens appear around the nodulated soybean rhizosphere, and to understand their diversity. Three leguminous plants of A. sinicus, M. sativa and Z repens were planted in the 31 soil samples to capture rhizobia. Rhizobia strains were isolated from different root nodules, and then phenotype and molecule identification were performed for them. To test the nodulating host scope, rhizobia isolates were inoculated to A. sinicus, M. sativa, T. repens and Glycine max. The capture results showed that both M. sativa and T, repens were nodulated in six different soil samples, whereas A. sinicus was nodulated in two soil samples. All together 14 representative rhizobia strains were isolated from the 14 root nodule samples. Similarity analysis of 16S rDNA genes identified the 14 representative rhizobia strains as Rhizobium genus. Phylogenetic tree of 16S rDNA genes indicated that the 14 representative stains were different species of Rhizobium genus. Nodulation test for each leguminous plants showed that the rhizobia strains could nodulate only the original leguminous plant but not any other. The research result indicated limited resource of Rhizobium astragali, R. meliloti and R. leguminosarum var. trifolii in the nodulated soybean rhizophere soil with rich Bradyrh＆obiumjaponicum of Sichuan, and that the limited rhizobia strains are of different genus from B. japonicum. The host specificity of rhizobia is also confirmed by the nodulation test.

关 键 词：根瘤菌 大豆根际土壤 紫云英 苜蓿 三叶草 

分 类 号：S154.3[农业科学—土壤学]