The concept of endophytes and their beneficial relationship with the plant is widely accepted as an important step in the co-evolution and diversity of plants. The symbiotic relationship between plants and fungi and rhizobia with legumes have a long evolutionary history. During exploration, fossils have shown close associations between endophytic fungi and plants roughly, 400 million years ago. The common symbiotic relationship between fungi and plants facilitated the evolution of large group of primary and secondarymetabolites of considerable chemical diversity, have a unique structure and high biological activity. During the last two decades, a growing interest in the study of endophytes, origin, biodiversity, interactions between endophytes and host plants, their role in ecology as well as biological activities of metabolites have been established. Several novel and beneficial activities for these microorganisms are evident by available literature, reveals their role as multifarious biologicals. The diversity and dynamics of endophyte populations, use of microbial inoculants to improve plant growth and health, and their role as a newbio-resource for metabolites are considerable interests of the twenty-first century. The exploration of active secondary metabolite is one of the most important reasons for the endophytes of industrial significance.
