荒漠植物黑沙蒿嫩枝与成熟枝内生菌群落结构差异

Difference in endophyte community structure between young and mature branches of Artemisia ordosica

摘要:

【背景】黑沙蒿是我国北方沙漠地区分布广泛、抗旱性能优良的固沙灌木，对稳定沙漠地区生态系统有至关重要的作用。【目的】内生菌在植物生命过程中扮演着重要角色，认识植物生长发育阶段幼嫩和成熟组织内生菌群的结构变化，对于理解菌群间的相互作用及保护宿主植物抵御生物和非生物胁迫具有积极意义。【方法】以宁夏拉巴湖林场黑沙蒿为研究对象，对其嫩枝和成熟枝木质化相关指标进行测定并对其内生菌群落进行高通量测序分析。【结果】黑沙蒿茎枝不同发育阶段木质素和纤维素差异显著，嫩枝内生细菌、真菌的多样性高于成熟枝，具有更多的OTU；成熟枝则通过木质素、纤维素的积累，表现出较高的环境适应能力；随着黑沙蒿茎枝的不断发育，内生真菌群落变化较为明显，优势门出现未识别真菌菌门替代子囊菌门的趋势。【结论】黑沙蒿茎枝不同发育阶段对植物微生物组的组装有深刻的影响，内生细菌和真菌微生物组在植物发育的不同阶段起着不同的生态作用。本研究揭示了黑沙蒿茎枝发育过程中内生细菌、真菌群落结构的差异，为荒漠地区生态恢复提供理论参考。

关键词:木质化;内生细菌;内生真菌;黑沙蒿

Abstract:

[Background] The drought-resistant sand-fixing shrub Artemisia ordosica, which is widely distributed in the desert area in northern China, plays an important role in stabilizing the ecosystem in desert area. [Objective] Endophyte plays an essential part in plant life. It is of great significance for understanding the interaction among microbial communities and protecting host plants against biotic and abiotic stresses to clarify the structure variation of endophytic communities in young and mature tissues of plants during growth and development. [Methods] In this study, we measured the lignification indices of young and mature branches of A. ordosica from Labahu Forest Farm in Ningxia and performed high-throughput sequencing of the endophyte communities. [Results] Content of lignin and cellulose was significantly different between A. ordosica branches at different development stages. The diversity of endophytic bacteria and fungi in young branches was higher than that in mature branches, and more OTUs were found in the former than in the later. Mature branches accumulated lignin and cellulose, thus boasting stronger adaptability. With the development of branches, endophytic fungal community changed more significantly, as the unidentified phylum gradually took the position of Ascomycota as the dominant phylum. [Conclusion] Development stage of A. ordosica branches has profound impact on the assembly of plant microbiome. Endophytic bacteria and fungi play different ecological roles at different development stages of plants. We revealed the difference in the community structure of endophytic bacteria and fungi between young and mature branches of A. ordosica, hoping to provide a reference for ecological restoration in desert area.

Key words:lignification;endophytic bacteria;endophytic fungi;Artemisia ordosica