竹叶兰根系共生真菌群落结构及生物学功能初探

Community structure and biological function of the root symbiotic fungi of Arundina graminifolia

为研究竹叶兰Arundina graminifolia根系共生真菌的群落结构及对寄主的营养作用,采用高通量测序技术对野生竹叶兰根围土壤、根表、根内3个生态位真菌的种类及生物学功能进行鉴定与预测。所测竹叶兰根系共生真菌的平均辛普森指数为根围0.972、根表0.905、根内0.703,说明3个位点都具有丰富的共生真菌;根围土壤真菌香农指数7.393显著高于根表和根内香农指数4.728和2.872,根表真菌多样性显著高于根内(P<0.05)。根表、根内有子囊菌门、担子菌门、罗兹壶菌门、壶菌门、毛霉菌门和被孢霉门,较根围土壤缺少球囊菌门和梳霉菌门;分子方差分析(AMOVA)证实3个生态位的真菌群落结构差异极显著(P=0.004)。各生态位丰度最高的20个真菌仅属于子囊菌和担子菌的40个属,其中子囊菌有30个属,种类数量占优势,而担子菌的单个种类丰度高于子囊菌。根围土壤腐生型真菌占优势(44.07%);根表主要有腐生、病原、共生型真菌;根内真菌营养类型差异大,样品M1的共生型真菌为优势类型(97.21%),M2、M3以腐生型占优(90.96%)。优势共生型真菌有革菌属Threlephora、根须腹菌属Rhizopogon和Dentiscutata,腐生型真菌主要有长毛孔菌属Funalia和Vuilleminia,均为担子菌。研究结果为揭示竹叶兰与根系真菌的营养关系以及共生真菌的开发提供了依据。

To study the community structure of the root symbiotic fungi of Arundina graminifolia and nutritional effect of the fungi on the host,high-throughput sequencing technology was used to identify the fungal species,and biological function of fungi in wild A.graminifolia rhizosphere soil(Rs),rhizoplane(Rp),and endoplane(Ep)was predicted.The average Simpson index of the root symbiotic fungi in Rs,Rp and Ep was 0.972,0.905,and 0.703 respectively,indicating that the three sites were rich in symbiotic fungi.The Shannon index in Rs was 7.393,significantly higher than that in Rp(4.728)and Ep(2.872),and fungal diversity in Rp was significantly higher than that in Ep(P<0.05).Ascomycota,Basidiomycota,Rozellomycota,Chytridiomycota,Mucoromycota and Mortierellomycota were mainly found in Rp and Ep.Glomeromycota and Kickxellomycota are absent in Rp and Ep.AMOVA analysis confirmed that the difference of fungal community structure between the three niches was extremely significant(P=0.004).The top 20 genera in each ecological niches only involve 40 genera of Ascomycota and Basidiomycota.Ascomycetous 30 genera are dominant,while the species richness of the single genus in Basidiomycota is higher than that in Ascomycota.The saprotrophic fungi dominated(44.07%)in Rs;Rp was mainly colonized by saprophytic,pathogenic and symbiotic fungi;the nutrient types of the fungi in Ep were different,by way of example,symbiotic fungi in sample M1 dominated(97.21%),while in M2 and M3 saprophytes dominated(90.96%).The dominant symbiotic genera are Threlephora,Rhizopogon and Dentiscutata.The saprophytic genera are mainly Funalia and Vuilleminia,belonging to basidiomycetes.Further study is needed for revealing the nutritional relationship between A.graminifolia and root symbiotic fungi.