Endophytes and Plants Interaction: A Hidden Microbial World Inside the Plant

Endophytes are a diverse group of microbes that colonize internal plant tissues without causing harm to the host. They play a crucial role in plant growth, development, and stress management. The is a complex mechanism involving evasive strategies to bypass host immune response, significant alteration in plant gene expression and establishment of a balance mutualistic relationship. Endophytes enhance plant health through various direct and indirect mechanisms, including the production of phytohormones such as auxin, gibberellins, and cytokinin. Moreover, they also solubilize nutrients, mainly nitrogen and phosphorus. A significant contribution of endophytes is the induction of induced systemic resistance (ISR), a defense response that primes the plant against a broad spectrum of pathogens and environmental stressors. The colonization of endophytes is governed by complex signaling pathways, immune modulation and tissue specificity, influenced by host genotype, age, and environmental conditions. This review highlights the ecological significance, mechanisms of colonization and functional contribution of endophytes to host plants. Furthermore, the review emphasizes that endophytes can recruit or influence other beneficial microbes in the rhizosphere region of host plants. Conclusively, this review synthesizes current understanding of the molecular strategies these microbes employ to survive within plant tissue and modulate plant immune system. We emphasize the immense, yet underexploited, potential of endophytes in enhancing plant resilience and productivity and advocates further research into their mechanisms and applications to meet growing demands of global agriculture.