22 - Tripartite interactions: plant-Pseudomonas putida-microRNAs in agricultural productivity

Abstract

Food and energy are two major emerging challenges faced by humans because of the increasing human population, decreasing fossil energy and global warming events. In such conditions, it is very difficult to grow crops and, thus, new methods are required to increase productivity. Beneficial rhizospheric bacteria known as plant growth-promoting rhizobacteria (PGPR), which have several plant growth promotion activities like P-solubilization, 1-aminocyclopropane-1-carboxylate deaminase activity, indole acetic acid and siderophore production, thereby improve seed germination, growth and plant yield, as well as defense responses towards phytopathogens. Pseudomonas putida (RA) strain MTCC5279 is a PGPR that have most of these PGP activities with the potential to enhance the plant growth and productivity in a sustainable manner. Recently, PGPR have also been reported to involve in amelioration of different abiotic stresses by controlling the various stress-responsive genes, morpho-physiological and biochemical parameters as well as modulation of stress-responsive microRNAs (miRNAs). miRNAs are 20–24 nt, noncoding, small regulatory RNAs reported to control the growth, development and metabolism of plants by controlling cellular, biological and molecular processes. PGPR-mediated modulation of miRNAs and their target genes involved in adaptive responses associated to sustainable growth and development of plants under various stresses. Moreover, significant changes in the expression conserved and putative novel miRNAs in P. putida-inoculated Arabidopsis and chickpea have been reported their involvement in the growth and development as well as drought stress amelioration. We address the current status of PGPR-mediated miRNA modulation as well as the growth and development of host plants during tripartite (plant-PGPR-miRNAs) interactions, and their role in the sustainable agricultural growth and productivity of plants.