Microbial Resources Division, Institute of Bioresources and Sustainable Development (IBSD), Takyelpat Institutional Area, Imphal, Manipur, 795001, India.
Department of Genetics, Osmania University, Hyderabad, Telangana, 500007, India.
Int Microbiol. 2020 May;23(2):241-251. doi: 10.1007/s10123-019-00097-x. Epub 2019 Aug 28.
The role of microflora is an indispensable part of the living organisms. Plants actively recruit specific microbial community to establish favorable habitat with the distinct microbiome, essentially unique for each species, offering new opportunities for plant growth and productivity. Umorok, an indigenous chili variety of northeastern India, production is highly affected by various factors; therefore, rhizosphere bacteria and their relationship with the root exudates released were analyzed to demonstrate rhizosphere bacterial impact on plant growth and health. Culturable and metagenomic bacterial DNA was characterized and the chemical nature of the root exudate was analyzed using chemotaxis assay after its basic analysis in HPLC. Juvenile stage exhibited diverse bacterial species of gammaproteobacteria, alphaproteobacteria, and actinobacteria but lacked the betaproteobacteria while the microbial diversity was reduced in flowering and fruiting stages. However, every growth stage maintained a similar amount of bacterial population regardless of diversity. The population of Pseudomonas, Bacillus, and Burkholderia species was increased several folds in flowering and fruiting stage. Further, the chemotaxis assay unveiled the advantage of root exudate chemical composition for specific microbial recruitment. The chemical composition analysis of root exudates showed substantial variation in the concentration of organic acids, phenolics, and flavonoids that are favoring unique bacterial species. Thus, root exudates confer and limit the related microbial population besides typical plant-bacterial synergetic association. This study emphasized information about the type of microbial load present in each growth stage, which is essential to develop a microbial consortia package for Umorok overall crop improvement.
微生物群的作用是生物活体不可或缺的一部分。植物积极招募特定的微生物群落，形成具有独特微生物组的有利栖息地，其本质上对每个物种都是独一无二的，为植物的生长和生产力提供了新的机会。印度东北部的本土辣椒品种乌莫罗克的产量受到各种因素的高度影响；因此，分析了根际细菌及其与根分泌物的关系，以证明根际细菌对植物生长和健康的影响。对可培养和宏基因组细菌 DNA 进行了表征，并在 HPLC 基本分析后使用趋化性测定分析了根分泌物的化学性质。幼年期表现出多样化的γ变形菌门、α变形菌门和放线菌门的细菌种类，但缺乏β变形菌门，而在开花和结果阶段微生物多样性减少。然而，无论多样性如何，每个生长阶段都保持着相似数量的细菌种群。在开花和结果阶段，假单胞菌、芽孢杆菌和伯克霍尔德菌的种群数量增加了数倍。此外，趋化性测定揭示了根分泌物化学组成对特定微生物招募的优势。根分泌物的化学组成分析显示，有机酸、酚类和类黄酮的浓度存在很大差异，有利于独特的细菌种类。因此，根分泌物除了典型的植物-细菌协同关系外，还赋予和限制了相关的微生物种群。这项研究强调了每个生长阶段存在的微生物负荷类型的信息，这对于开发乌莫罗克整体作物改良的微生物联合体包至关重要。
