Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641003, India.
J Microbiol Biotechnol. 2012 Mar;22(3):301-10. doi: 10.4014/jmb.1109.09025.
Prosopis juliflora and Parthenium hysterophorus are the two arid, exotic weeds of India that are characterized by distinct, profuse growth even in nutritionally poor soils and environmentally stressed conditions. Owing to the exceptional growth nature of these two plants, they are believed to harbor some novel bacterial communities with wide adaptability in their rhizosphere. Hence, in the present study, the bacterial communities associated with the rhizosphere of Prosopis and Parthenium were characterized by clonal 16S rRNA gene sequence analysis. The culturable microbial counts in the rhizosphere of these two plants were higher than bulk soils, possibly influenced by the root exudates of these two plants. The phylogenetic analysis of V1_V2 domains of the 16S rRNA gene indicated a wider range of bacterial communities present in the rhizosphere of these two plants than in bulk soils and the predominant genera included Acidobacteria, Gammaproteobacteria, and Bacteriodetes in the rhizosphere of Prosopis, and Acidobacteria, Betaproteobacteria, and Nitrospirae in the Parthenium rhizosphere. The diversity of bacterial communities was more pronounced in the Parthenium rhizosphere than in the Prosopis rhizosphere. This culture-independent bacterial analysis offered extensive possibilities of unraveling novel microbes in the rhizospheres of Prosopis and Parthenium with genes for diverse functions, which could be exploited for nutrient transformation and stress tolerance in cultivated crops.
刺槐和豚草是印度的两种干旱外来杂草，其特点是即使在营养贫瘠的土壤和环境胁迫条件下，也能旺盛生长。由于这两种植物具有特殊的生长特性，人们认为它们的根际可能存在一些具有广泛适应性的新型细菌群落。因此，在本研究中，通过克隆 16S rRNA 基因序列分析，对与刺槐和豚草根际相关的细菌群落进行了表征。这两种植物根际的可培养微生物数量高于土壤总量，这可能受到这两种植物根分泌物的影响。16S rRNA 基因 V1_V2 结构域的系统发育分析表明，与土壤总量相比，这两种植物根际存在更广泛的细菌群落，主要包括刺槐根际的酸杆菌门、γ-变形菌纲和拟杆菌门，以及豚草根际的酸杆菌门、β-变形菌纲和硝化螺旋菌门。与刺槐根际相比，豚草根际的细菌群落多样性更为明显。这种无需培养的细菌分析为揭示刺槐和豚草根际中具有多种功能基因的新型微生物提供了广泛的可能性，这些微生物可用于养分转化和栽培作物的抗胁迫。
