Endophytic Phytobiomes as Defense Elicitors: Current Insights and Future Prospects

The endophytes are microbial organisms inhabiting within the plant body either intercellularly or intracellularly. Earlier these endophytes were considered either as pathogenic or having no significant role in the plant’s physiology and metabolism, but with the advancement of research and technology, the critical roles played by them are emerging. These endophytes form a symbiotic relationship with their host where in exchange of nutrient and habitat, they provide the plant protection against various stresses both biotic and abiotic. They provide the protection or resistance through either direct mechanisms or indirectly by eliciting various pathways within their host plants against the stresses. The endophytes help the host plant to acclimatize under harsh conditions by eliciting the defense-related genes, which in response triggers the concerned pathways for the synthesis of secondary metabolites for plant defense. A better understanding of the mechanisms and the role of endophytes in stress management will help in designing defense strategies to cope with the stresses and to improve integrated strategies for stress management in agriculture. The chapter thus explores the various mechanisms with the endophytes eliciting both biotic and abiotic defense responses in their host plants under stress conditions and their future application in agriculture and crop sciences.