Diversity and the role of endophytic bacteria: a review

Endophytes belong to a widespread group of microorganisms that colonise intracellular and intercellular spaces in all known plant parts but do not cause diseases or major morphological changes to the host. Endophytic bacteria ubiquitously colonise plant internal tissues, where they can form a variety of interactions, including commensalistic, symbiotic, trophobiotic and mutualistic. Endophytic bacteria produce pharmaceutically important compounds such as antimicrobials, antioxidants, industrial enzymes, antidiabetics and anti-cancer agents. In addition, endophytes can also support their host by producing a variety of natural products for potential use in medicine, agriculture or industry. This group of bacteria can have a tremendous impact on plant communities, raising their fitness by endowing tolerance to biotic and abiotic stress. There are great prospects for searching, selecting and studying new endophytic bacteria species in order to create new microbial preparations for adaptive crop production, while reducing the environmental impacts of agriculture. The present review summarises studies to date about endophytic bacteria, including topics such as isolation methods, the diversity of these bacteria and their biological roles.