高通量测序分析重庆地区茅苍术根际丛枝菌根真菌多样性

Arbuscular mycorrhizal fungi diversity in rhizosphere soil of Atractylodes lancea (Thunb.) DC. in Chongqing region by high-throughput sequencing

摘要:

【背景】丛枝菌根真菌(arbuscular mycorrhizal fungi，AMF)是土壤微生物区系中分布最广泛的一类菌根真菌，能与地球上90%的维管植物形成共生体，可通过调节植物的生理代谢过程增强植物的抗逆性。【目的】揭示重庆地区中药材茅苍术根际土壤中AMF的结构与组成，解析土壤因子对AMF类群的影响。【方法】以重庆地区茅苍术主产地彭水县、秀山县、石柱县、南川区和酉阳县2?3年生茅苍术根际土壤为材料，利用Illumina MiSeq 2500测序平台进行真菌扩增子测序，分析不同地点土壤的茅苍术根际AMF类群组成和多样性的差异。【结果】茅苍术的菌根侵染率均在50%以上，每10 g风干土壤中孢子含量在50个以上，最高达到144个。根际土壤共检测到球囊菌门Glomeromycota的3纲4目8科9属AMF，包括Glomus、Claroideoglomus、Gigaspora、Paraglomus、Archaeospora、Ambispora、Acaulospora、Diversispora和Scutellospora，其中前6属为5个区县土样共有。球囊霉属(Glomus)相对丰度最高，达67%，为所有地区茅苍术根际样本中的优势类群。冗余度分析(redundancy analysis，RDA)表明，土壤pH对AMF群落组成影响最大。pH、有机质、碱解氮、速效钾与Shannon指数呈正相关，有效磷与之呈负相关；各土壤因子与Simpson指数的相关性则相反。5个土壤因子均与丰度(Chao1)指数呈负相关。另外，pH、有机质与均匀度(ACE)指数呈正相关；碱解氮、速效钾、有效磷与之呈负相关。【结论】茅苍术根际土壤中AMF资源丰富，土壤因子对AMF群落组成和丰度影响显著，是导致AMF群落结构地理分布格局差异的重要原因之一。

Abstract:

[Background] Arbuscular mycorrhizal fungi (AMF) is the most widely distributed mycorrhizal fungus among soil microflora. They can form mycorrhizal symbiosis with more than 90% of the vascular plants, and enhance the plant’s resistance by regulating the plant’s physiological and metabolic processes. [Objective] To reveal the structure and composition of AMF in rhizosphere soil of Chinese herbal medicine Atractylodes lancea (Thunb.) DC. from Chongqing area, and to analyze the influence of soil factors on AMF groups. [Methods] Using rhizosphere soils of A. lancea (Thunb.) DC. collected from Pengshui, Xiushan, Shizhu, Nanchuan and Youyang counties in Chongqing as material, to analyze the differences in the composition and diversity of AMF from different locations and soils via high-throughput sequencing. [Results] The mycorrhizal infection rate of A. lancea (Thunb.) DC. was more than 50%, and the content of soil spores was more than 50 per 10 g of air dried soil, and the highest number was 144. Three classes, 4 orders, 8 families and 9 genera of Glomeromycota including Glomus, Claroideoglomus, Gigaspora, Paraglomus, Archaeospora, Ambispora, Acaulospora, Diversispora and Scutellospora were detected in rhizosphere soil. The first six genera were common to soil samples of five counties. Glomus had the highest relative abundance of 67%, which was the dominant group in all samples. RDA analysis showed that soil pH had the greatest effect on AMF community composition. Soil pH, organic matter, alkaline nitrogen and available potassium were positively correlated with Shannon index, while available phosphorus was negatively correlated. The correlation between each soil factor and Simpson index was opposite. Five soil factors were negatively correlated with Chao1 index. In addition, pH and organic matter were positively correlated with ACE index, while alkaline nitrogen, available potassium and available phosphorus were negatively correlated. [Conclusion] The rhizosphere soil of A. lancea (Thunb.) DC. is rich in AMF resources, and soil factors have significant effects on the composition and abundance of AMF community, which is one of the important reasons for the difference of AMF community structure and geographical distribution pattern.