内生细菌广泛分布于植物各种组织和器官的细胞间隙或细胞内。过去的研究多集中于普通的高等植物，而苔藓植物内生细菌的研究较少。少数国外学者及本实验室的初步研究表明在个体微小的苔藓植物中确实存在着丰富的内生细菌，其潜在的功能显示它们与苔藓植物具有较强的适应性和抗逆性有关。因此，系统地研究与不同苔藓植物共生的内生细菌的多样性，发掘有益的细菌资源，并探讨其共生机制成为本研究的重点。本研究拟从西藏极端环境地区选取不同类别的苔藓植物，利用培养法和基于细菌16S rDNA的DNA和RNA水平的克隆文库技术对其内生细菌的群落结构及多样性进行分析和比较；并将分离鉴定的内生细菌侵染无菌的宿主植物，同时结合从薻苔和台湾拟金发藓中分离鉴定的两株新菌的基因组测序，根据它们在宿主中的迁移和定殖规律和有效的基因组信息来分析内生细菌在宿主中的功能。本研究对于发掘更多抗逆性强的细菌资源、了解细菌和苔藓植物的共生机制意义重大。

Endophytic bacteria were widely distributed in the intracellular and intercellular spaces of all kinds of plant tissues and organs. Most related research was concentrated on the common plants, and seldom was made on the endophytes of bryophytes.The primary studies by fewer foreign scientists and our lab showed that the abundant endophytic bacteria were indeed existed in the small plants of bryophytes, which potential functions displayed the relationship to the stronger adaption and stresses resistance of bryophytes.Thus, the key of this project was designed by doing the deeply systematic work on the endophytic bacterial community structure and diversity in different bryophytes, discovering the beneficial bacterial resources and analysing their symbiosis mechanism.To do this , we plan to sample the different bryophytes from Tibet, an extreme environment area; and then made the analysis and comparison of their endophytic bacterial community structure and diversity by using traditional cultural method and bacterial 16S rDNA- based clone library technique; then the isolated endophytes were infected to the sterile hosts and combined with the genome sequencing of two new strains isolated from Takakia lepidozioides and Polytrichastrum formosum in order to make an analysis on the functions of the endophytes in the hosts according to their moving and colonization characteristics and effective genome information. This research would be helpful to discovering much more bacterial resources with the stronger stresses resistance and understanding the symbiosis mechanism between bryophytes and endophytes.