湖南红壤区三个林龄板栗园外生菌根真菌多样性

Diversity of ectomycorrhizal fungi in three Castanea mollissima plantations in krasnozem region of Hunan Province

板栗Castanea mollissima是我国重要的生态经济树种,同时也是外生菌根(ectomycorrhizal,EcM)依赖型树种。为揭示湖南红壤区板栗EcM真菌多样性,本研究以9、17和35年3个不同林龄的板栗园为研究对象,利用Illumina Miseq测序平台对不同林分的板栗根部EcM样品ITS区进行高通量测序,分析板栗EcM真菌的多样性及其在不同林龄中的分布情况;同时测定板栗根际土壤理化性质,运用线性回归、Spearman相关性以及典型对应相关分析(canonical correspondence analysis,CCA)等,研究土壤因子与板栗EcM真菌多样性之间的关系。结果表明:3个林龄中的菌根样品测序得到EcM真菌可操作分类单元(operational taxonomic units,OTUs)46个,隶属于2门3纲8目13科18属。硬皮马勃属Scleroderma、粉孢牛肝菌属Tylopilus和红菇属Russula是板栗园中主要的EcM菌属。9年林分EcM真菌Shannon多样性指数最大(1.33),与35年林分Shannon多样性指数(0.22)有显著差异,各林龄物种丰富度指数无显著差异。线性回归分析发现土壤pH、全钾、速效钾、有效铁、有效钙和有效镁与EcM真菌的多样性呈显著负相关。结合CCA分析和相关性分析,发现土壤pH、全磷、全钾、速效钾及有效钙是影响湖南省红壤区板栗园EcM真菌群落组成的主要土壤因子。湖南红壤地区板栗EcM真菌群落组成较为丰富,为EcM真菌筛选及板栗园种植管理提供科学依据。

Castanea mollissima is an important ecological and economical tree species,also ectomycorrhizal(EcM)dependent tree species in China,and EcM fungal diversity of C.mollissima orchards with different ages of 9 years,17 years and 35 years in krasnozem region of Hunan Province was investigated.High-throughput sequencing of the ITS region of C.mollissima root EcM samples from different stands was carried out by Illumina MiSeq sequencing platform.The diversity and distribution of EcM fungi in different stands of C.mollissima were analyzed,and physical and chemical properties of C.mollissima rhizosphere soil were determined.Based on linear regression,Spearman correlation and canonical correlation analysis(CCA),the relationship between soil factors and the diversity of C.mollissima EcM fungi was studied.Forty six EcM fungal operational taxonomic units(OTUs)were detected,belonging to 2 phyla,3 classes,8 orders,13 families,and 18 genera.Scleroderma,Tylopilus and Russula were the main EcM genera in C.mollissima orchards.The Shannon diversity index of EcM fungi in the 9-year stand was the largest(1.33),which was significantly different from that in the 35-year stand(0.22).However,there was no significant difference in species richness index among different forest ages.Linear regression analysis showed that soil pH,total potassium(TK),available potassium(AK),available iron(Fe),available calcium(Ca)and available magnesium(Mg)were significantly negatively correlated with the diversity of EcM fungi.The CCA analysis and Spearman analysis suggested that soil pH,total phosphorus(TP),TK,AK and available Ca were the main soil factors affecting the composition of EcM fungal communities in C.mollissima orchards in krasnozem of Hunan Province.The fungal community composition of EcM fungi of C.mollissima is relatively rich in the krasnozem region of Hunan Province,and this study provides a scientific information for the selection of EcM fungi and planting management of C.mollissima orchards.