马尾松不同叶型幼苗外生菌根真菌群落特征

马尾松Pinus massoniana当年生幼苗中会出现全初生叶和全次生针叶两种变异类型,它们的根系生长以及外生菌根（ectomycorrhiza,ECM）真菌群落是否也表现出差异,截止目前尚不明晰。本研究以马尾松全初生叶及全次生针叶幼苗类型为材料,采集幼苗根系,利用万深LA-S植物根系分析系统测定根系形态,采用TTC法测定根系活力,利用IonS5 ^TMXL平台对根系真菌DNA扩增子区进行高通量测序,探析马尾松幼苗变异类型与根系构型及ECM真菌群落之间的关系。结果表明：两种类型幼苗的根系构型存在显著差异,全次生针叶幼苗的根系总长度、表面积、体积、分叉数以及根系活力等参数比全初生叶幼苗的高16%-44%。测序所得ECM真菌序列可划分为44个OTUs,隶属2门5纲9目13科15属。ECM真菌群落组成上,小球孢盘菌属Sphaerosporella为马尾松两种类型幼苗共有优势属,其在全初生叶幼苗ECM真菌中占比达95.59%,但在全次生针叶幼苗ECM真菌中仅占60.43%,同时全次生针叶幼苗ECM真菌中须腹菌属Rhizopogon也占有较高比例,为16.43%。ECM真菌群落多样性分析结果显示,马尾松全次生针叶幼苗中Shannon多样性指数、Chao 1与Ace丰富度指数均显著高于全初生叶幼苗。

Community structure characteristics of ectomycorrhizal fungi in different leaf type seedlings of Pinus massoniana

There are two variations of one-year-old Pinus massoniana seedlings,one with primary needles and another with secondary needles.However,it is still poorly understood that whether there are variations in root morphology and ectomycorrhiza(ECM)fungal community between these seedlings.In this study,the seedlings’roots of the two variants were collected to analyze root morphology by WANSHEN LA-S system and measure root activity by TTC method,and DNA ITS regions of the fungi in roots were sequenced with IonS5 TMXL platform.The results showed that there were significant differences in the root system of the seedlings.The total root length,surface area,volume,number of branching,and root activity of the seedlings with secondary needles were 16%to 44%higher than those of the seedlings with primary needles.The DNA sequences of ECM fungi were classified into 44 OTUs belonging to 2 phyla,5 classes,9 orders,13 families,and 15 genera.Sphaerosporella was dominant genera,reaching 95.59%of total genera in the seedlings with primary needles,and 60.43%in the seedlings with secondary needles.Rhizopogon also occupied a higher proportion(16.43%)of ECM fungi in the seedlings with secondary needles.Shannon diversity index,Chao 1,and Ace abundance index of ECM fungi of the seedlings with secondary needles were significantly higher than those of the seedlings with primary needles.