Endophytic Microbiomes and Their Plant Growth-Promoting Attributes for Plant Health

Endophytes reside within internal tissues of living plants without causing any harm to the host. The influence of these microbial communities on plant growth, yield, stress, and disease resistance, has been identified as potential research priorities in agriculture. In this chapter, we aim to explore the diverse host–endophyte interactions for plant growth promotion and health. Initially, the colonization of endophytes in specific plant tissues is discussed along with their mechanism of entry, habitat selection, response to stimuli, and evasion of the plant immunity. Endophytic microbes promote plant growth through different types of direct and indirect mechanisms. Plant growth-promoting endophytes (PGPE) play a vital role in phytohormone production, nutrient acquisition, nitrogen fixation, and solubilization of minerals. Further, indirect mechanisms (like suppression of plant pathogens by producing volatile organic compounds, antagonizing agents, and quorum quenchers) are also discussed in detail. Siderophores production and the secretion of different hydrolytic enzymes like chitinases, glucanases, and proteases also help in the induction of systemic resistance and protection of the host plants. Bioactive metabolites derived from endophytes serve as excellent therapeutic agents and have potential applications in agriculture, cosmetics, pharmaceutical, and food industries. Hereby, this chapter highlights the scientific rationale behind using endophytic microbiomes as potential biofertilizers, biopesticides, and biocontrol agents.