Kalam Sadaf, Das Subha Narayan, Basu Anirban, Podile Appa Rao
Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India.
J Basic Microbiol. 2017 May;57(5):376-385. doi: 10.1002/jobm.201600588. Epub 2017 Apr 11.
Rhizosphere microbial community has diverse metabolic capabilities and plays a crucial role in maintaining plant health. Oligotrophic plant growth promoting rhizobacteria (PGPR), along with difficult-to-culture microbial fractions, might be involved synergistically in microbe-microbe and plant-microbe interactions in the rhizosphere. Among the difficult-to-culture microbial fractions, Acidobacteria constitutes the most dominant phylum thriving in rhizospheric soils. We selected effective PGPR for tomato and black gram and studied their effect on population densities of acidobacterial members. Three facultatively oligotrophic PGPR were identified through 16S rRNA gene sequencing as Sphingobacterium sp. (P3), Variovorax sp. (P4), and Roseomonas sp. (A2); the latter being a new report of PGPR. In presence of selected PGPR strains, the changes in population densities of Acidobacteria were monitored in metagenomic DNA extracted from bulk and rhizospheric soils of tomato and black gram using real time qPCR. A gradual increase in equivalent cell numbers of Acidobacteria members was observed over time along with a simultaneous increase in plant growth promotion by test PGPR. We report characterization of three effective PGPR strains and their effects on indigenous, underexplored difficult-to-culture phylum-Acidobacteria. We suggest that putative interactions between these two bacterial groups thriving in rhizospheric soils could be beneficial for plant growth.
根际微生物群落具有多样的代谢能力，在维持植物健康方面发挥着关键作用。贫营养型植物促生根际细菌（PGPR）以及难以培养的微生物组分可能协同参与根际中的微生物-微生物和植物-微生物相互作用。在难以培养的微生物组分中，酸杆菌门是根际土壤中最主要的优势门类。我们筛选了对番茄和黑豆有效的PGPR，并研究了它们对酸杆菌门成员种群密度的影响。通过16S rRNA基因测序鉴定出三株兼性贫营养型PGPR，分别为鞘氨醇单胞菌属（P3）、贪铜菌属（P4）和玫瑰单胞菌属（A2）；后者是关于PGPR的新报道。在选定的PGPR菌株存在的情况下，利用实时定量PCR监测从番茄和黑豆的根际土壤和 bulk土壤中提取的宏基因组DNA中酸杆菌门的种群密度变化。随着时间的推移，观察到酸杆菌门成员的等效细胞数逐渐增加，同时测试的PGPR对植物生长的促进作用也同步增强。我们报道了三株有效PGPR菌株的特性及其对根际土壤中本地的、未充分研究的难以培养的酸杆菌门的影响。我们认为，这两类在根际土壤中共同存在的细菌之间可能存在的相互作用对植物生长有益。
