Biotic stress alleviation: A sneak peek into the beneficial taxa in rhizosphere

Abstract

Biotic stress is a known cause of considerable agricultural loss, and reducing this loss is crucial for enhancing crop productivity and achieving global food security. Although plants are sessile, they have well-equipped beneficial microbial neighbors in the rhizosphere that can be shaped and recruited to meet their needs, especially during periods of stress. Multiple factors stimulate shifts within beneficial microbes, especially the most malleable bacterial groups, to favour their host, and numerous studies have revealed how biotic stress strongly alters the rhizosphere taxa of plants to predominantly Proteobacteria, Firmicutes and Actinomycetes. To this end, the Actinomycetes-members of these bacterial taxa have been applied as beneficial bioinoculants to control diseases in plants with a dearth utilization of their metabolites (including antibiotics) as chemo-control agents against phytopathogens. Therefore, this review examines how biotic stress shapes key bacterial taxa in the rhizosphere and highlights the potential of Actinomycetes-derived antibiotics and other metabolites to mitigate biotic stress through direct antagonism of pathogens as well as inducing plant defense. This chemo-control approach could potentially replace synthetic chemicals in mitigating biotic stress for crop productivity.