Microbial phytohormones: the potential orchestrators of plant growth and defense
Ruchi Tripathi, T. Aravind, Sumit Kumar, Chetan Keswani, Satyendra Pratap Singh, Rashmi Tewari, A. K. Tewari, Krishna Pratap Singh, Tatiana Minkina
Abstract
Plants are subjected to an array of biotic stresses that can have an altered consequence on the overall plant morphology and physiology. Various mechanisms involving different pathways are stimulated in the host plants to tolerate or avoid the stress effects that are triggered during changes in the regular metabolic process. Phytohormones (PHs) are one of the key regulators largely governing the plant growth response to environmental cues along with having a crucial role in plant defense stimulation against different stresses. Some of these PHs such as cytokinin, gibberellin, salicylic acid, auxin, and ethylene are also produced by the beneficial microbes. The beneficial microbe diversity plays a potential role in the disease prevention and can be executed as a biological marker in plant defense strategies. An array of PHs of microbial origin has been reported that are working in multifaceted signaling network in response to varied developmental and environmental clues. These hormone signaling pathways are used by the plants in dual ways either for initiating the growth responses or the defense responses against the invading pathogen. Keeping in view the role of PHs and microbial phytohormone production capability, we propose their implication in sustainable agriculture.