Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan; Department of Biology, Lahore Garrison University, Lahore, Pakistan.
Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan.
Microbiol Res. 2019 Apr;221:36-49. doi: 10.1016/j.micres.2019.02.001. Epub 2019 Feb 4.
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.
内生细菌是在植物体内茁壮成长的植物有益细菌，它们可以在正常和挑战条件下改善植物的生长。它们可以通过改善植物养分吸收和调节与生长和应激相关的植物激素来直接有益于宿主植物。间接的，内生细菌可以通过使用抗生素、水解酶、营养限制以及植物防御的启动来靶向害虫和病原体，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殖植物的内皮层。这种定植是通过一系列涉及运动性、附着性、植物聚合物降解和逃避植物防御的特性来实现的。内生定殖者的多样性取决于几种细菌、植物和环境特定因素。一些内生细菌具有广泛的宿主范围，可以用作生物接种剂，以开发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、宿主特异性和植物生长促进机制的因素。该综述还强调了用于研究内生群落的各种方法、野生植物作为新型内生细菌的来源，以及可能改善植物-内生菌关联的创新方法。此外，还讨论了在植物体内表达的细菌基因以及研究它们的挑战。
