山桐子叶际微生物群落多样性、结构及功能预测分析

Diversity,structure and function prediction of phyllospheric microorganism community in Idesia polycarpa

【目的】山桐子是优良的木本油料树种,叶片是山桐子植株的一个关键器官,分析健康与感病山桐子叶际微生物群落的丰富度、多样性、群落组成以及功能预测,为探明山桐子病害特征及发病机理,科学开展山桐子林地抚育管理提供参考依据。【方法】采用Illumina平台对健康与感病山桐子叶际微生物群落DNA片段进行双端(Paired-end)测序。通过Vsearch软件聚类获取OTUs,根据其在不同样本的分布,评估每个样本的Alpha多样性水平,进一步衡量不同样本间的物种丰度组成差异;根据基因测序结果,预测菌群代谢功能。【结果】1)健康山桐子和感病山桐子的叶际细菌运算分类单位(OTUs)分别为212和198个,叶际真菌OTUs分别为101和79个。针对山桐子叶际微生物的研究表明,健康山桐子叶际细菌及真菌的丰富度和多样性均高于感病叶片。2)山桐子叶际细菌以不动杆菌属Acinetobacter为优势菌属,在健康和感病植株中相对丰度分别为32.67%和24.90%;健康山桐子叶际真菌以链格孢属Alternaria(17.41%)、亚隔孢壳属Didymella(15.44%)为优势菌属,感病山桐子叶际真菌以链格孢属(54.77%)为优势菌属。相比于健康山桐子,感病山桐子叶际真菌中链格孢属相对丰度大幅升高,可能是关键致病菌属。3)PICRUSt2功能预测山桐子叶际细菌群落共得到6个一级功能层、34个二级功能层,在代谢方面功能较为活跃;真菌群落共得到5个一级功能层、29个二级功能层,主要功能类群为生物合成、前体代谢物和能量的产生。【结论】健康山桐子植株叶际细菌及真菌丰富度和多样性均高于感病植株,链格孢属真菌可能是山桐子感病的关键因子;与代谢、生物合成及能量产生有关的微生物群落是活跃度最高的。

【Objective】Idesia polycarpa is a good woody oil species,leaf blade is a key organ of I.polycarpa.The richness diversity,community composition and function prediction of phyllospheric microorganism community of healthy and susceptible I.polycarpa were analyzed to provide a reference for exploring the characteristics and pathogenesis of I.polycarpa disease and scientifically developing the management of I.polycarpa forest.【Method】Illumina platform was used to sequencing the DNA fragments of healthy and susceptible phyllospheric microorganism community in I.polycarpa.Vsearch software was used to obtain OTUs,and the Alpha diversity level of each sample was evaluated according to its distribution in different samples to further measure the difference in species abundance composition among different samples.According to the results of gene sequencing,the metabolic function of bacterial community was predicted.【Result】1)There were 212 and 198 interfoliar bacterial operational taxa(OTUs)in healthy and susceptible I.polycarpa,respectively,and 101 and 79 interfoliar fungal OTUs(OTUs).The results showed that the abundance and diversity of bacteria and fungi in healthy I.polycarpa leaves were higher than those in susceptible leaves.2)Acinetobacter was the dominant bacterium in I.polycarpa,and the relative abundance of healthy and susceptible plants was 32.67%and 24.90%respectively.Alternaria(17.41%)and Didymella(15.44%)were the dominant genera of healthy I.polycarpa interfoliar fungi,while Alternaria(54.77%)was the dominant genera of susceptible I.polycarpa interfoliar fungi.Compared with healthy I.polycarpa,the relative abundance of Alternaria in the interfoliar fungi of susceptible I.polycarpa increased significantly,which might be the key pathogen genus.3)Six first-order and 34 second�order functional layers were found in the interleaf bacterial community of I.polycarpa,which were active in metabolism.Fungal communities were divided into 5 primary functional layers and 29 secondary functional layers,and the main functional groups were biosynthesis,precursor metabolites and energy production.【Conclusion】The abundance and diversity of interfoliar bacteria and fungi in healthy I.polycarpa are higher than those in susceptible plants,and Alternaria fungi may be the key factor of I.polycarpa disease.The microbial community associated with metabolism,biosynthesis and energy production are the most active as predicted.