Structural and functional diversity of plant growth promoting microbiomes for agricultural sustainability

Abstract

The plant allied microbes are phyllospheric, endophytic, and rhizospheric that is allied with plants eco-systems. These microbes have are termed as plant growth promoting (PGP) microbes as they have an ability to enhance growth of plant through indirectly or directly PGP mechanisms. The PGP microbes improve the growth and development of plant under both normal and diverse abiotic stresses conditions of temperatures, pH, salinity and drought. The microbes uses subsequent mechanism to stimulate the plant growth like biological nitrogen fixation; solubilization of minerals (P, K and Zn); production of phyto-hormones (Indole acetic acid, cytokinin and gibberellic acid); 1-aminocyclopropane-1-carboxylate deaminase attributes; production of extracellular hydrolytic enzymes (amylase, cellulase, chitanase, pectinase, protease, and xylanase), siderophores, hydrogen cyanide and ammonia. The PGP microbes sorted out from soil and plant associated are belong to several phylum of all three domain, that is, Archaea, Bacteria and Eukarya with predominant species of genera Arthrobacter, Pseudomonas, Aspergillus, Bacillus, Burkholderia, Colletotrichum, Exiguobacterium, Flavobacterium, Fusarium, Halobacillus, Haloferax, Lysinibacillus, Paenibacillus, Penicillium, Psychrobacter, Sediminibacillus, Streptomyces, Trichoderma, and Virgibacillus. In agriculture PGP microbiomes potentiality has increased steadily as it is an effective way to reduce the use of different chemical-based fertilizer, pesticide and other supplements. Present progress on research related to PGP microbial diversity (plant and soil microbiomes), along with their colonizing capability and action’s mechanism should increase their applications for plant growth and disease management of agricultural system toward the agricultural sustainability. Present review deals with the structural and functional diversity of PGP microbiomes for agricultural sustainability.