Endophytic bacteria are the plant beneficial bacteria that thrive inside plants and can improve plant growth under normal and challenging conditions. They can benefit host plants directly by improving plant nutrient uptake and by modulating growth and stress related phytohormones. Indirectly, endophytic bacteria can improve plant health by targeting pests and pathogens with antibiotics, hydrolytic enzymes, nutrient limitation, and by priming plant defenses. To confer these benefits, the bacteria have to colonize the plant endosphere after colonizing the rhizosphere. The colonization is achieved using a battery of traits involving motility, attachment, plant-polymer degradation, and evasion of plant defenses. The diversity of endophytic colonizers depends on several bacteria, plant and environment specific factors. Some endophytic bacteria can have a broad host range and can be used as bioinoculants in developing a safe and sustainable agriculture system. This review elaborates the factors affecting diversity of bacterial endophytes, their host specificity and mechanisms of plant growth promotion. The review also accentuates various methods used to study endophytic communities, wild plants as a source of novel endophytic bacteria, and innovative approaches that may improve plant-endophyte association. Moreover, bacterial genes expressed in planta and challenges to study them are also discussed.

内生细菌是对植物有益的细菌，可在植物内部生长并在正常和富挑战性的条件下改善植物的生长。它们可以通过改善植物对养分的吸收以及调节生长和胁迫相关的植物激素而直接使寄主植物受益。间接地，内生细菌可以通过使用抗生素，水解酶，营养限制剂和启动植物防御来针对害虫和病原体，从而改善植物健康。为了赋予这些益处，细菌必须在定殖根际后定植在植物内球上。通过一系列涉及运动，附着，植物多聚体降解和逃避植物防御的性状来实现定殖。内生殖民者的多样性取决于几种细菌，植物和环境的特定因素。一些内生细菌可以具有广泛的宿主范围，并且可以用作生物安全剂，用于发展安全和可持续的农业系统。这篇综述阐述了影响细菌内生菌多样性，其宿主特异性和植物生长促进机制的因素。审查还强调了用于研究内生群落的各种方法，作为新型内生细菌来源的野生植物以及可改善植物与内生植物结合的创新方法。而且，细菌基因表达 审查还强调了用于研究内生群落的各种方法，作为新型内生细菌来源的野生植物以及可改善植物与内生植物结合的创新方法。而且，细菌基因表达 审查还强调了用于研究内生群落的各种方法，作为新型内生细菌来源的野生植物以及可改善植物与内生植物结合的创新方法。而且，细菌基因表达还讨论了植物的研究和挑战。