青藏高原垫状点地梅叶际及内生可培养微生物多样性

Diversity of phyllospheric and endophytic culturable microorganisms in Androsace tapete of the Qinghai-Tibetan Plateau

摘要:

【背景】垫状点地梅作为青藏高原最具代表性的垫状植物，其叶际和内生微生物对适应极端环境有重要意义，同时也是一种独特的资源。【目的】探究垫状点地梅叶际和叶内可培养微生物多样性，以及不同生存状态个体之间的微生物差异。【方法】采用纯培养方法分离和纯化3个不同地区垫状点地梅叶际和叶内的细菌、酵母菌和丝状真菌，并用16S rRNA基因和ITS区域序列进行分析鉴定。【结果】最终得到叶际微生物350株，鉴定为22属49种，优势种为Penicillium sajarovii；内生微生物274株，鉴定为19属45种，优势种为Bacillus mycoides；两者的优势属均为Penicillium。垫状点地梅叶际和叶内之间及不同生存状态个体之间微生物的α多样性大多无显著差异，各群落间的成员也有重叠，但物种组成存在显著的空间异质性。【结论】垫状点地梅叶际和叶内有着丰富的可培养微生物资源，来源于不同生存状态的个体或不同部位的微生物物种组成差别较大，微生物对不同环境的选择偏好形成了不同的群落模式。但这些不同来源的微生物群落之间同样存在高比例的共有菌株，这些共有菌株的异养方式和生态位并不固定，可兼共生和腐生生存，生存空间也无明确的界限。纯化的菌株可为日后功能菌株的开发利用提供材料。

Abstract:

[Background] Androsace tapete is the representative cushion plant species on the Qinghai-Tibetan Plateau, and the phyllospheric and intrafoliar microorganisms are important for this species to adapt to the extreme environment and are also a unique resource. [Objective] To investigate the diversity of phyllospheric and endophytic culturable microorganisms in A. tapete and the differences in the microorganisms between living and dead individuals. [Methods] Phyllospheric and intrafoliar bacteria, yeasts, and filamentous fungi were isolated from A. tapete in three different regions by pure culture, purified, and identified based on 16S rRNA and ITS sequence analysis. [Results] A total of 350 phyllospheric strains (49 species in 22 genera) were identified, with the dominant species of Penicillium sajarovii, and 274 endophytic culturable strains (45 species in 19 genera) were screened out, with the dominant species of Bacillus mycoides. The two shared the dominant Penicillium. The difference in alpha diversity between phyllospheric and intrafoliar microorganisms of A. tapete and between the living and dead individuals was mostly not significant. The communities shared some members, but there was significant spatial heterogeneity in species composition. [Conclusion] There are abundant culturable phyllospheric and intrafoliar microbial resources in A. tapete, and the species composition was remarkably different between living and dead individuals and between different parts of the leaf, and the selection preferences of microorganisms for different environments result in different community patterns. However, the microbial communities from different sources shared a high proportion of strains, and the heterotrophic mode and ecological niche of these shared strains are not fixed. The heterotrophic pattern and the niches of the shared strains are not fixed. They can survive by both symbiosis and saprophytism, and the living space has no clear boundary. The purified strains can be used for the development and utilization of functional strains.