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.