Department Of Environmental Science And Technology

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Author: search.filters.author.Rathi, ManohariHas files: No

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    Role of Quorum Sensing in the Survival of Rhizospheric Microbes
    (Springer Nature, 2022-01-01T00:00:00) Rathi, Manohari; Manchanda, Geetanjali; Singh, Raghvendra Pratap
    Quorum sensing (QS) signaling is a cell-to-cell communication or coordination at microbial population level. However, the ecological role of QS in complex or multi-species communities, principally in the milieu of community assemblage, has neither been experimentally discovered nor theoretically revealed. QS comprises the production of secreted signals (diffusible), which can diverge across diverse types of microbes. Over the past decades, there has been a significant accretion of data of the molecular mechanisms, gene regulons, signal structures, and behavioral responses related with QS systems gained. More recent studies have focused on understanding quorum sensing in the context of bacterial sociality. Studies of the role of quorum sensing in cooperative and competitive microbial interactions have discovered, how QS coordinates interactions both within and between the species. Such studies of quorum sensing as a social behavior have relied on the development of �synthetic ecological� models that use nonclonal bacterial populations. Hence, the aim of this chapter is to understand how microbes might interact with one another in the plant root�associated soils using QS system. � The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021.
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    Brevundimonas diminuta MYS6 associated Helianthus annuus L. for enhanced copper phytoremediation
    (Elsevier Ltd, 2020-08-31T00:00:00) Rathi, Manohari; K N, Yogalakshmi
    Natural occurring metal-tolerant microbial population have replaced conventional expensive metal remediation approach since the last few years. The present study focuses on investigating the potential of a copper-tolerant plant growth promoting rhizobacterial strain Brevundimonas diminuta MYS6 for Cu bioremediation, plant growth promotion and Cu uptake in Helianthus annuus L. Box-Behnken Design of response surface methodology optimized the influencing parameters such as pH, temperature and Cu concentration. At optimized conditions of pH (5), temperature (32.5 �C) and Cu concentration (250 mg/L), the rhizobacteria followed a sigmoid growth curve pattern with maximum Cu removal of 94.8% in the stationary phase of growth. Cu exposed Brevundimonas diminuta MYS6 produced increased EPS (18.6%), indicating their role in internal defence against Cu stress. The FTIR analysis suggested the role of carboxylic acids, alcohols and aliphatic amine groups in Cu bioremoval. Furthermore, the results of pot experiments conducted with Helianthus annuus L. var. CO4 and Brevundimonas diminuta MYS6 showed enhanced plant growth and Cu uptake. The rhizobacteria increased root and shoot length, fresh and dry plant biomass and leaf chlorophyll by 1.5, 1.7, 9.9, 15.8 and 2.1 fold. The plant biomass mediate enhanced Cu uptake in roots and shoots was found to be 2.98 and 4.1 folds higher when compared to non-inoculated treatment. Henceforth the results of the study evidence the rhizobacterial strain Brevundimonas diminuta MYS6 as an efficient bio-inoculant for copper remediation. � 2020 Elsevier Ltd