Microbial Consortia-Mediated Plant Defense against Phytopathogens and Growth Benefits

Microorganisms under natural habitats live in communities and some provide benefits to plants. The concept of development of microbial consortia for bio-control and crop sustainability relies on this fact. Microbes when introduced to soil as consortium interact with a host plant, partially mimic the natural soil conditions. To improve stability of the released microbes in different agricultural fields, use of microbial consortia is advocated. Further, microbes together can also offer multiple mechanisms of mycoparasitism, competition, antibiosis, induced systemic resistance etc., to fight pathogens. Microbes in communities also strengthen the capabilities of the partners in an additive or synergistic manner. Although development of microbial consortia is important for management of plant diseases, it is also equally important to understand how they influence plant metabolism when the consortium is introduced to soil. Various plant physiological parameters that are identified to aid biocontrol by pathogens include activation of phenyl propanoid pathway, activation of antioxidant pathways and various stress enzymes such as phenyl alanine ammonia lyase, peroxidase and polyphenol oxidase etc. The compatible microbial consortia trigger defence responses in an enhanced level in crop plants than the microbes alone, and provides better protection against pathogens. Evaluation of compatibility and synergism of microbial components is essential for the success of microbial consortia. Further rapid evaluation methodologies or kits need to be developed for quicker developments in the field of microbial consortia.