Compatibility of rhizobial genotypes within natural populations of Rhizobium leguminosarum biovar viciae for nodulation of host legumes
Compatibility of rhizobial genotypes within natural populations of Rhizobium leguminosarum biovar viciae for nodulation of host legumes
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DOI：
10.1128/aem.69.4.2276-2283.2003
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发表时间：
2003-04-01
影响因子：
4.4
通讯作者：
Amarger, N
中科院分区：
文献类型：
--
作者：
Laguerre, G;Louvrier, P;Amarger, N
从两种大块土壤、根际以及生长在相同土壤中的寄主豆类、蚕豆 (Vicia faba) 和豌豆 (Pisum sativum) 的根瘤中采集了豆科根瘤菌 (Rhizobium leguminosarum) 的种群样本。还分析了在其他土壤中生长的其他结瘤豌豆、蚕豆和野豌豆（Vicia sativa）种群以及来自不同地理位置的蚕豆结瘤菌株。根瘤菌的特征是重复的外基因组回文 PCR 指纹和/或 16S-23S 核糖体 DNA 基因间间隔区的 PCR 限制性片段长度多态性 (RFLP) 作为基因组背景的标记，以及结瘤基因区域 nodD 的 PCR-RFLP 作为基因组共生成分的标记。成对比较显示了大块土壤、根际和根瘤种群的遗传结构之间的差异，以及野豆科交叉接种组内宿主特异性程度的差异。对于蚕豆，共生基因型似乎是根瘤菌基因型成功占据根瘤的主要决定因素，与相关的基因组背景、植物基因型和采样的土壤无关。一种特定的根瘤菌共生基因型与蚕豆之间的相互作用似乎对于结瘤具有高度特异性，并且与固氮效率相关。与大块土壤和蚕豆结瘤种群相比，对豌豆结瘤种群的分析表明，基因组背景和共生基因型之间存在优先关联。根瘤菌基因组的两个组成部分都可能影响豌豆结瘤的竞争力，根际定植可能是竞争根瘤占据的决定性步骤。
Populations of Rhizobium leguminosarum biovar viciae were sampled from two bulk soils, rhizosphere, and nodules of host legumes, fava bean (Vicia faba) and pea (Pisum sativum) grown in the same soils. Additional populations nodulating peas, fava beans, and vetches (Vicia sativa) grown in other soils and fava bean-nodulating strains from various geographic sites were also analyzed. The rhizobia were characterized by repetitive extragenomic palindromic-PCR fingerprinting and/or PCR-restriction fragment length polymorphism (RFLP) of 16S-23S ribosomal DNA intergenic spacers as markers of the genomic background and PCR-RFLP of a nodulation gene region, nodD, as a marker of the symbiotic component of the genome. Pairwise comparisons showed differences among the genetic structures of the bulk soil, rhizosphere, and nodule populations and in the degree of host specificity within the Vicieae cross-inoculation group. With fava bean, the symbiotic genotype appeared to be the preponderant determinant of the success in nodule occupancy of rhizobial genotypes independently of the associated genomic background, the plant genotype, and the soil sampled. The interaction between one particular rhizobial symbiotic genotype and fava bean seems to be highly specific for nodulation and linked to the efficiency of nitrogen fixation. By contrast with bulk soil and fava bean-nodulating populations, the analysis of pea-nodulating populations showed preferential associations between genomic backgrounds and symbiotic genotypes. Both components of the rhizobial genome may influence competitiveness for nodulation of pea, and rhizosphere colonization may be a decisive step in competition for nodule occupancy.