Abstract

Under natural conditions plants are not individual entities; they are associated with diverse microbiota to form the plant holobiont. The concept of plant holobiont is being actively explored to address the issues related to plant’s health. Endophytes are a class of plant-associated microbes, which reside within the internal tissues of plants. They have been ubiquitously reported in all plants investigated so far. The plant-endophyte interactions may exhibit different modes of symbiotic association, ranging from beneficial (mutualism), neutral (commensal), to even pathogenic. Although we have a fair idea of the factors affecting plant-microbe interactions, the intricacies involved in fine-tuning their association are just beginning to unfold. Some of the pertinent questions surrounding the plant-endophyte symbiosis include: how are endophytes different from other beneficial microbes like rhizobia, mycorrhizae, and rhizobacteria? What mechanisms ensure that endophytes gain an unsurpassed entry and colonization into plants without eliciting a strong defense reaction? Why do different strains of the same microbial species enter into diverse modes of symbiotic association with plants? What factors cause the switch in the lifestyle of endophytes? In the present review, these questions have been addressed in the light of recent data and finally, concluded with gaps in endophyte research, which could be deliberated in future endeavors.

摘要

在自然条件下，植物不是个体。它们与各种微生物群相关联，从而形成植物全生命周期。为了解决与植物健康有关的问题，正在积极探索植物全生命周期的概念。内生细菌是一类与植物相关的微生物，位于植物的内部组织中。迄今为止，在所有调查过的植物中都普遍报道了它们。植物与内生菌的相互作用可能表现出不同的共生关联模式，范围从有益（互惠），中性（共生）到甚至是致病性。尽管我们对影响植物与微生物相互作用的因素有一个清晰的认识，但微调它们之间的关联所涉及的复杂性才刚刚开始显现。有关植物-内生菌共生的一些相关问题包括：内生菌与其他有益微生物如根瘤菌，菌根和根瘤菌有何不同？哪些机制可确保内生菌获得无与伦比的进入和定植到植物中而不会引起强烈的防御反应？为什么同一微生物物种的不同菌株会进入与植物共生关联的多种模式？哪些因素导致内生菌生活方式的改变？在本综述中，这些问题已根据最近的数据得到了解决，最后以内生菌研究的不足作为结论，可以在今后的工作中加以探讨。和根瘤菌？哪些机制可确保内生菌获得无与伦比的进入和定植到植物中而不会引起强烈的防御反应？为什么同一微生物物种的不同菌株会进入与植物共生关联的多种模式？哪些因素导致内生菌生活方式的改变？在本综述中，这些问题已根据最近的数据得到了解决，最后以内生菌研究的不足作为结论，可以在今后的工作中加以探讨。和根瘤菌？哪些机制可确保内生菌获得无与伦比的进入和定植到植物中而不会引起强烈的防御反应？为什么同一微生物物种的不同菌株会进入与植物共生关联的多种模式？哪些因素导致内生菌生活方式的改变？在本综述中，这些问题已根据最近的数据得到了解决，最后以内生菌研究的不足作为结论，可以在今后的工作中加以探讨。