羌塘高原地区藓状雪灵芝根际土壤细菌多样性研究

Bacteria diversity study on rhizosphere soil of Arenaria bryophylla in Qiangtang Plateau region

关键词:  藓状雪灵芝, 根际土壤细菌, 群落组成, 多样性, 功能预测

Key words:  Arenaria bryophylla, rhizosphere soil bacteria, community composition, diversity, functional prediction

摘要:

藓状雪灵芝(Arenaria bryophylla)主要分布于海拔5 000 m附近的极端环境,是高原地区重要的藏药植物之一。为探究高原藓状雪灵芝根际土壤细菌多样性,该文采用高通量测序技术,对不同地区的藓状雪灵芝根际土壤细菌多样性与群落组成特征进行研究。结果表明:(1)3个采样点根际土壤细菌α多样性无显著性差异,但细菌群落结构组成显著不同( P<0.05 ); 3个采样点根际土壤细菌群落的优势门均为变形菌门和厚壁菌门,优势属组成存在差异; 根际土壤细菌群落的连接以正相关为主,表现出协同作用。(2)光照强度、铵态氮、速效磷和有机物显著影响藓状雪灵芝根际土壤细菌组成( P<0.05 ),光照强度的解释度最高。(3)COG功能基因家族和KEGG代谢通路预测显示,氨基酸转运和代谢、碳水化合物的运输和代谢是优势功能,不同地区的优势功能基因存在显著性差异( P<0.05 )。综上认为,羌塘高原不同地区藓状雪灵芝根际土壤细菌群落结构组成存在显著性差异,光照强度等环境因子显著影响细菌群落组成且不同地区根际土壤细菌功能表现出分异性。该研究结果为青藏高原传统藏药藓状雪灵芝的研究提供了理论基础,也为进一步了解藓状雪灵芝对青藏高原恶劣环境的适应性进化提供了参考依据。

Abstract:

Arenaria bryophylla, which is mainly distributed in extreme environments at an altitude of about 5 000 m, is one of the important Xizang medicinal plants in the plateau region. To explore the bacterial diversity in the rhizosphere soil of A. bryophylla in the Qiangtang grassland of northern Xizang, China, this study used high-throughput sequencing technology to investigate the diversity and community composition of rhizosphere soil bacteria from A. bryophylla at different sites. The results were as follows:(1)There was no significant difference in the α-diversity of rhizosphere soil bacteria among the three sampling sites, but the bacterial community composition was significantly different(P<0.05). The dominant phyla of the bacterial communities in the rhizosphere soil at all three sampling sites were Proteobacteria and Firmicutes, while the composition of dominant genera differed. Correlation network analysis showed that the connections within the rhizosphere soil bacterial communities were mainly positive, indicating synergistic effects.(2)Light intensity, ammonium nitrogen, available phosphorus, and organic matter significantly affected the composition of bacteria in the rhizosphere soil of A. bryophylla(P<0.05), with light intensity having the highest explanatory power.(3)Predictions of COG functional gene families and KEGG metabolic pathways showed that amino acid transport and metabolism, and carbohydrate transport and metabolism were the dominant functions, and there were significant differences in the dominant functional genes among different regions(P<0.05). In conclusion, there are significant differences in the composition of the bacterial community in the rhizosphere soil of A. bryophylla in different regions of the Qiangtang Plateau. Environmental factors such as light intensity significantly affect the bacterial community composition, and the functions of rhizosphere soil bacteria in different regions show differentiation. This study provides a theoretical basis for the research on A. bryophylla as a traditional Xizang medicine on the Qinghai-Xizang Plateau, and also provides a reference for further understanding the adaptive evolution of A. bryophylla to the harsh environment of the Qinghai-Xizang Plateau.