Genetic characterization of root-nodule bacteria associated with Acacia salicina and A. stenophylla (Mimosaceae) across south-eastern Australia
Genetic characterization of root-nodule bacteria associated with Acacia salicina and A. stenophylla (Mimosaceae) across south-eastern Australia
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DOI：
10.1099/ijs.0.021014-0
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发表时间：
2011-02-01
影响因子：
2.8
通讯作者：
Thrall, Peter H.
中科院分区：
文献类型：
--
作者：
Hoque, Mohammad S.;Broadhurst, Linda M.;Thrall, Peter H.
豆科植物和固氮土壤微生物之间的共生关系在全世界植物群落中具有重要的生态意义。例如，营养贫乏的澳大利亚土壤通常以灌木豆科植物（例如金合欢属植物）为主。然而，相对较少的研究量化了这些生态上重要的植物-微生物相互作用的多样性、宿主特异性和有效性的模式。在这项研究中，使用 16S rRNA 基因序列和 PCR-RFLP 分析来检查从澳大利亚东南部两种广泛分布的豆科植物（Acacia salicina 和 Acacia stenophylla）的根瘤中分离出的细菌菌株，分布范围遍及近 60 个地点。结果表明，微生物种群存在广泛的遗传多样性，包括广泛的新基因组物种。虽然之前的研究表明，大多数澳大利亚本土豆科植物主要与慢生根瘤菌属的物种结瘤，但我们的研究结果表明，与其他根瘤形成细菌属的成员有显着关联，包括根瘤菌属、Ensifer、Mesorhizobium、伯克霍尔德氏菌属、叶杆菌属和德沃西亚属。遗传分析还揭示了多种非结瘤细菌内生菌，之前仅记录了其中的一个子集。尽管这些内共生体的生态作用尚不清楚，但它们可能在促进植物生长、结瘤和疾病抑制方面发挥直接和间接作用。
Symbiotic relationships between legumes and nitrogen-fixing soil micro-organisms are of ecological importance in plant communities worldwide. For example, nutrient-poor Australian soils are often dominated by shrubby legumes (e.g. species of Acacia). However, relatively few studies have quantified patterns of diversity, host-specificity and effectiveness of these ecologically important plant-microbe interactions. In this study, 16S rRNA gene sequence and PCR-RFLP analyses were used to examine bacterial strains isolated from the root nodules of two widespread south-eastern Australian legumes, Acacia salicina and Acacia stenophylla, across nearly 60 sites. The results showed that there was extensive genetic diversity in microbial populations, including a broad range of novel genomic species. While previous studies have suggested that most native Australian legumes nodulate primarily with species of the genus Bradyrhizobium, our results indicate significant associations with members of other root-nodule-forming bacterial genera, including Rhizobium, Ensifer, Mesorhizobium, Burkholderia, Phyllobacterium and Devosia. Genetic analyses also revealed a diverse suite of non-nodulating bacterial endophytes, only a subset of which have been previously recorded. Although the ecological roles of these endosymbionts are not well understood, they may play both direct and indirect roles in promoting plant growth, nodulation and disease suppression.