Biofilm producing Bacillus vallismortis TR01K from tea rhizosphere acting as plant growth promoting agent

Abstract

Microbial biofilms are an aggregation of single or multi-species bacteria that acquires the capacity to adhere to any surface where they can act like a wholesome system chemically “speaking with” each other through quorum sensing. This synergism is very prominently noticed in the rhizospheric regions of plant roots subsequently forming a dome which can protect the root-rhizospheric niche from various biotic and abiotic stress. The bacterial EPS have a number of roles like adhesion, cohesion and aggregation of soil particles, retaining water molecules, acts as a potential barrier on the rhizospheric regions, facilitating ionic and genetic information exchange within the matrix component, enhanced production of plant readily available nutrients etc. Keeping this scenario in mind, this study was formulated on to isolate and explore novel rhizobacteria with colossal biofilm forming ability showing great potential as a source of lignocellulolytic plant growth promoting agent.The crop chosen for this study was tea or Camellia sinensis, a quintessential beverage that is consumed across the globe. The rhizospheric region of a woody plant like tea, acts as a hub for lignocellulosic enzyme producing bacteria. The novel rhizobacteria isolated from cultivated tea soil, Bacillus vallismortis TR01K [NCBI Genbank Accession Number MT672714], was found to have an immense biofilm forming potential that ranged approximately 40x times higher than normal standard bacterial biofilm forming potentials when tested under laboratory conditions. Further in vitro characterizations of the novel strain showed it's immense potential to make plant nutrient available, to produce plant growth hormones (IAA, GA3, Cytokinin) and produce plant stress mitigating hormone (ACC deaminase). Lignocellulolytic enzymes are a vital part of lignocellulosic biomass degradation-a sustainable biotechnological approach for enzymes, organic acids, feed and biofuel production. The selected bacteria was tested elaborately for the family of lignocellulolytic enzymes (cellulase, laccase, lignin peroxidase, pectinase, amylase, chitinase, beta glucanase etc.) which showed promising results. Thus, proving the entire set of experiments in compliance with the aforementioned hypothesis that the novel bacterial isolate from tea rhizosphere has a significant biofilm forming potential with a colossal potency for being lignocellulolytic plant growth promoting agent.