Bacterial Endophytes, a resilient way toward sustainable agriculture: provide plant growth promotion and biocontrol of plant pathogens

Plant pathogens are considered a major constraint in decreasing the quality and quantity of plants and plant products by attacking the seed from its germination to the harvesting stage. To date, various multifunctional chemical pesticides have been applied to control these infectious entities, but these chemical pesticides are not as effective in controlling them. That is why "bacterial endophytes," an alternative to these chemical pesticides, have been determined in the history of mankind through multidisciplinary ways. At the same time, these endophytes work to save the living environment, improve plant growth, and control infectious plant pathogens. The current study summarizes and analyzes the pioneering and recent works on plant bacterial endophytes and their mechanisms as biocontrol agents/plant growth promotion, interaction with the host plant, root colonization, systemic colonization of aerial plant tissues, phytohormone production and modulation, host specificity, genes expressed in the endosphere, multi-omics approaches to improve endophyte use, and biopesticide formulation by these bacterial endophytes. The manuscript highlights the most necessary information about bacterial endophytes, and the study will play a vital role in the further use and handling of these bacterial endophytes for sustainable agricultural production.