黑老虎内生真菌及根际土壤真菌的群落结构与生态功能分析

Community structure and ecological function analyses of endophytic and rhizosphere soil fungi in Kadsura coccinea

关键词:  黑老虎, 高通量测序, ITS, 内生真菌, 根际土壤真菌, 多样性, FUNGuild

Key words:  Kadsura coccinea, high-throughput sequencing, ITS, endophytic fungi, rhizosphere soil fungi, diversity, FUNGuild

摘要:

为探讨黑老虎(Kadsura coccinea)根际土壤和组织内生真菌菌群的组成及其生态功能,该研究采用ITS高通量测序技术对成熟黑老虎(根、茎、叶)内生真菌及根际土壤真菌群落结构、多样性和生态功能进行了分析。结果表明:(1)从12个样品中共获得2 241个可操作分类单元(OTU),涉及10门、41纲、95目、212科、367属,内生真菌(根、茎、叶)和根际土壤真菌OTU数分别为386、536、258、1 435个,其中共有的OTU为18个。在门水平上,黑老虎内生真菌及根际土壤真菌优势群落均为子囊菌门和担子菌门,其中子囊菌门在叶和茎中占比分别高达96.99%和95.37%; 在属水平上,黑老虎根际土壤真菌中腐生真菌被孢霉属占比较高(为13.5%),叶和茎等生长旺盛的组织中子囊菌门未分类属和痂囊腔菌属占比较高。(2)α多样性分析结果显示,黑老虎根际土壤真菌群落的丰度和多样性明显高于内生真菌,茎中内生真菌丰度显著高于根和叶,而根、茎和叶组织间内生真菌多样性差异不显著; PCoA分析结果显示,叶和茎的真菌群落结构相似性更高。(3)利用FUNGuild数据库进行的功能预测分析结果显示,黑老虎根际土壤真菌和内生真菌含有大量的未分类菌群; 功能已分类菌群中,病理寄生型功能群在生长旺盛的组织中占比较高。该研究结果为黑老虎优异功能菌的筛选和发掘提供了理论依据。

Abstract:

To investigate rhizosphere soil and endophytic fungal community structure, diversity, and ecological function in Kadsura coccinea, the endophytic fungal communities from roots, stems, leaves, and rhizosphere soils of mature K. coccinea were analyzed based on ITS high-throughput sequencing technology. The results were as follows:(1)A total of 2 241 operational taxonomic units(OTUs)were obtained from 12 samples at 97% of sequence homology level. The OTUs of endophytic(root, stem and leaf)and rhizosphere soil fungi were 386, 536, 258 and 1 435, respectively, of which 18 OTUs were in common. They belonged to 10 phyla, 41 classes, 95 orders, 212 families and 367 genera. The dominant fungal communities at the phylum level in the endophytic and rhizosphere soil of K. coccinea were Ascomycota and Basidiomycota. Among them, Ascomycota accounted for 96.99% and 95.37% of the endophytic fungal community in leaves and stems, respectively. At the genus level, the saprophytic fungi Mortierella accounted for a relatively high proportion(13.5%)in the rhizosphere soil. In contrast, pathogenic fungi such as Ascomycota_unclassified and Elsinoe were mainly found in vigorously growing tissues(leaves and stems).(2)Alpha diversity analysis showed that the richness and diversity of the fungal community in the rhizosphere soil of K. coccinea were significantly higher than those in endophytic fungi. Although the abundance of endophytic fungi in stems was significantly higher than that in roots and leaves, the differences in endophytic fungal diversity among roots, stems and leaves were not significant. The principal component analysis(PCoA)revealed that the fungal community structures of leaves and stems were more similar, and those of roots and rhizosphere soils were more similar.(3)The function of fungal communities in different tissues and rhizosphere soils of K. coccinea was predicted and analyzed by using FUNGuild platform. The results showed that the rhizosphere soil fungi and endophytic fungi contained a large number of unclassified fungi. Among the functionally classified fungi, the pathotroph functional group had a higher proportion in the vigorously growing tissues. This study provides a theoretical basis for the screening and exploring of active functional fungi in K. coccinea.