青枯病易感和钝感桑树品种根际土壤真菌群落结构比较

为研究青枯病易感和钝感桑树品种植株根际土壤真菌群落组成,该研究以ITS1F和ITS2R为引物,基于高通量测序技术对桑树青枯病易感品种(台湾长果桑,SM)和桑树青枯病钝感品种(桂桑12号,IM)植株根际土壤真菌群落结构进行分析。结果表明:(1)两个品种间指示真菌丰富度的ACE、Chao1指数及表征多样性的Shannon指数无显著差异,门分类水平,被孢霉门(Mortierellomycota)和球囊菌门(Glomeromycota)是青枯病钝感桑树品种植株根际土壤中特有的优势真菌门; 而属分类水平,Apiotrichum、地丝菌属(Geotrichum)、足放线病菌属(Scedosporium)和腐质霉属(Humicola)等是青枯病易感桑树品种植株根际土壤中富集的特有优势真菌属。(2)青枯病易感桑树品种植株根际土壤中,缺失了被孢霉门、球囊菌门真菌,以及被孢霉属(Mortierella)、镰刀菌属(Fusarium)、曲霉菌属(Aspergillus)和毛壳菌属(Chaetomium)等具有生防功能的优势真菌门属,可能是其易感青枯病的重要原因。(3)根据真菌群落对同类环境资源的利用途径进行功能预测发现,青枯病易感桑树品种根际土壤中,富集了相对较多的病理营养型和腐生营养型真菌; 而青枯病钝感桑树品种根际土壤中,富集了相对丰富的共生营养型真菌。(4)特有真菌数量更为丰富的土壤真菌OTU分类水平,可能是青枯病钝感桑树品种田间表现出更强抗性的重要原因。可见,在青枯病钝感桑树品种植株根际土壤中,富集的被孢霉属、镰刀菌属、曲霉菌属和毛壳菌属等优势特异真菌属,具有作为拮抗桑树青枯病备选菌属的潜力。

Comparison of fungal community structures in rhizosphere soil between sensitive and insensitive mulberry varieties to bacterial wilt

To reveal the resistant mechanism of fungal community structures in rhizosphere soil of sensitive and insensitive mulberries to bacterial wilt. Based on high-throughput sequencing technology, using ITS1F and ITS2R as primers, fungal community structures in rhizosphere soil between sensitive mulberry(Taiwan Morus macroura)and insensitive mulberry(Guisang 12)to bacterial wilt were analyzed. The results were as follows:(1)Although the indexes of soil fungal richness and diversity, such as ACE, Chao1 and Shannon were not significantly different between sensitive and insensitive mulberry varieties, but at phylum level, Mortierellomycota and Glomeromycota were the unique soil dominant fungi in rhizosphere soil of sensitive mulberry variety to bacterial wilt. At genus level, in comparison to the insensitive mulberry variety to bacterial wilt, Apiotrichum, Geotrichum, Scedosporium and Humicola were the special soil dominant fungi in rhizosphere soil of sensitive mulberry variety to bacterial wilt.(2)Compared to the insensitive mulberry variety, some soil fungal phyla and genera, such as Glomeromycota and Mortierellomycota, Mortierella, Fusarium, Aspergillus and Chaetomium were all lost in rhizosphere soil of sensitive mulberry variety to bacterial wilt. It suggests that higher abundance and diversity of soil fungal community structure in rhizosphere soil of insensitive mulberry variety to bacterial wilt were the important reasons for its higher resistance to bacterial wilt.(3)Based on the functional prediction according to the utilization pathways of fungal communities under similar environmental resources, higher abundance of pathotrophic and saprotrophic fungi enriched in rhizosphere soil of bacterial wilt susceptible mulberry varieties; On the contrary, higher abundance of symbiotrophic fungi enriched in rhizosphere soil of bacterial wilt resistant mulberry varieties.(4)Higher abundant soil unique fungi at OTU taxonomic level in rhizosphere of bacterial wilt resistant mulberry variety maybe can be considered as the important reason for its higher bacterial wilt resistant ability. The results suggest that Mortierella, Fusarium, Aspergillus and Chaetomium can be considered as the candidate antagonistic fungi for bio-controlling bacterial wilt in the rhizosphere soil of insensitve mulberry varieties to bacterial wilt.