女贞叶、茎、根及根际土壤真菌群落结构及功能群特征

Characteristics of Community Structure and Functional Group of Fungi in Leaf,Stem,Root and Rhizosphere Soil of Ligustrum lucidum

【目的】探明女贞不同营养器官和根际土壤真菌群落的物种组成、多样性和功能群特征,为研究女贞及其相关真菌的互作关系及开发利用女贞内生和根际真菌资源奠定基础,同时为林木微生物组研究提供参考。【方法】以女贞叶、茎、根和根际土壤为研究对象,基于真菌rRNA基因ITS1区,应用Illumina MiSeq高通量扩增子测序技术,结合生物信息学分析,解析女贞内生和根际土壤真菌群落的多样性、物种组成及功能群特征,并比较其群落结构差异。【结果】女贞叶、茎、根和根际土壤真菌丰富度排序为根际土壤>茎>根>叶,多样性为根际土壤>叶>茎>根。4种样品共有的OTU为31个,占OTU总数的2.08%。在叶、茎和根内分别有39.42%、35.26%和76.94%的OTU同时存在于根际土壤中。β-多样性分析表明,β多样性分析表明,叶的真菌群落结构与茎较为相似,而与根和根际土壤差异较大生态位的真菌群落结构存在显著差异(R=0.8981,P<0.01)。在门水平上,叶、茎、根和根际土壤真菌群落的优势菌均为子囊菌门和担子菌门;在属级水平上,叶、茎内生真菌的优势属为枝孢属和维希尼克氏酵母属,根内优势属为Rhexodenticula和普可尼亚属,根际土壤的优势属为裸盖菇属和Saitozyma。叶、茎、根及根际土壤共有的真菌主要包括枝孢属、维希尼克氏酵母属、Saitozyma、Rachicladosporium、Symmetrospora、链格孢属及青霉菌属。在真菌功能群分类中,叶、茎、根和根际土壤真菌功能群分类呈现地上和地下部分分化的特征,叶和茎中的真菌以复合营养型(病理-腐生-共生营养型、病理-腐生营养型)为主,分别占叶和茎真菌功能群的76.97%和91.68%,而根和根际土壤中的真菌以单一营养型(腐生营养型、共生营养型)为主,分别占60.05%和67.51%。【结论】女贞根际土壤的真菌多样性显著高于叶、茎和根。叶的真菌群落结构和功能群特征与茎较为相似,但与根和根际土壤差异较大。在叶和茎中,真菌功能群以病理-腐生-共生营养型为主,而根和根际土壤中的真菌功能群以腐生营养型为主。

【Objective】This study aimed to explore the species composition,diversity and functional group characteristics of fungal community in three vegetative organs and rhizosphere soil of Ligustrum lucidum,so as to lay a foundation for the privet-fungi interaction study and the development and utilization of the privet endophytic and rhizosphere fungal resources.This research could provide a reference for the study of trees microbiome.【Method】The leaf,stem,root and rhizosphere soil of L.lucidum were selected as research objects,and the ITS1 region of fungal rRNA gene was sequenced by Illumina MiSeq instrument.Based on the sequencing result,the diversity,species composition,functional group characteristics and their difference in community structure of fungal community in three vegetative organs and rhizosphere soil were analyzed subsequently.【Result】The species richness of fungal community of different samples was in the order of RS>SE>RE>LE,and the community diversity was RS>LE>SE>RE.There were 31 OTUs in the four samples,accounting for 2.08%of the total OTUs.Approximately 39.42%,35.26%and 76.94%of OTUs in leaves,stems and roots were also found in rhizosphere soil,respectively.Theβdiversity analysis showed that the fungal community structure of leaf was relatively similar to that of stem,but was different from that of root and rhizosphere soil.At the phylum level,the dominant taxon of fungi in the four compartments were Ascomycota and Basidiomycota.At the genus level,the dominant fungi of endophytic fungi community in leaves and stems were Cladosporium and Vishniacozyma while the dominant fungi in the root were Rhexodenticula and Pochonia.In addition,the dominant fungi of rhizosphere soil were Psilocybe and Saitozyma.The common fungi in leaves,stems,roots and rhizosphere soil mainly were Cladosporium,Vishniacozyma,Saitozyma,Rachicladosporium,Symmetrospora,Alternaria and Penicillium.The statistical result of fungi functional group classification showed that the differentiation characteristics of samples could be divided into aboveground and underground parts with the fungi in leaves and stems were mainly of compound trophic(pathotrophy-saprotrophy-symbiotrophy,pathotrophy-saprotrophy),which accounted for 76.97%and 91.68%,respectively,while those were mainly of single trophic fungi(saprotrophy,symbiotrophy)in root and rhizosphere soil,accounting for 60.05%and 67.51%,respectively.【Conclusions】The diversity of fungal community in rhizosphere soil is significantly higher than that in leaves,stems and roots of L.lucidum.The fungal community structure and functional group characteristic of leaves are relatively similar to that of stems,but significantly different from those of roots and rhizosphere soil.The fungi functional group in leaves and stems is mostly pathotrophy-saprotrophy-symbiotrophy,while that in root and rhizosphere soil is mostly saprotrophy.