东北红松纯林菌根外生菌根真菌群落与环境因子的相关性

外生菌根是木本植物根系与真菌形成的共生结构,外生菌根真菌在红松等外生菌根树种的定植与森林生态系统的保持方面起到至关重要的作用。明确菌根系统内外生菌根真菌群落组成是揭示菌根共生机制的前提条件。本研究利用Illumina Hiseq测序平台对生长季内红松纯林内根围土壤及菌根样品ITS2区进行高通量测序,分析其外生菌根真菌群落结构随季节的变化规律,同时通过统计学的方法分析了红松根系微生态中外生菌根真菌群落结构组成变化与其他生物因素、非生物因素的相关性。结果如下：（1）从6月份到10月份,5个月的菌根样品测序共得到741个真菌OTUs,利用FUNGuild数据库分析,其中85个OTUs归类为外生菌根真菌,优势属（相对丰度>5）为蜡壳菌属Sebacina、乳牛肝菌属Suillus、Meliniomyces、红菇属Russula、棉革菌属Tomentella、须腹菌属Rhizopogon和缘腺革菌属Amphinema。6月份菌根中外生菌根真菌的多样性最大,显著高于其他月份。（2）红松林外生菌根真菌群落组成受到土壤pH、有效磷含量、有效钾含量和土壤有效氮含量的影响,它们与外生菌根真菌优势属相对丰度呈现正相关或负相关。（3）根围土壤内真菌是影响红松根系外生菌根真菌相对丰度的另一重要因素,其中,包括普可尼亚属Pochonia、产丝齿菌属Hyphodontia、镰刀菌属Fusarium、Collembolispora、枝穗霉属Clonostachys、Apodus、鹅膏属Amanita在内的土壤真菌与根内外生菌根真菌的相对丰度呈线性关系。同时,超过85%的根内外生菌根真菌与同一取样地的土壤共有,可以认为侵染和扩散是红松根内外生菌根真菌群落形成的主要方式,同时兼有植物根系的选择,因为根内并不包括所有土壤中存在的外生菌根真菌,其机制需要进一步人工模拟试验验证。

Correlation between ectomycorrhizal fungal community and environmental factors in Pinus koraiensis forest in Northeast China

ITS2 region of ectomycorrhizal fungi (EcMF) in root tips and rhizosphere soil of Korean pine Pinus koraiensis in Northeast China was sequenced by using Illumina Hi-Seq platform. The correlations between EcMF community and climate factors, soil physical and chemical properties were analyzed statistically. 741 OTUs were obtained from root tips collected from June to October, and 85 OTUs of them were classified as EcMF according to FUNGuild database. The dominant EcMF genera in roots were Sebacina, Suillus, Meliniomyces, Russula, Tomentella, Rhizopogon and Amphinema. The diversity of EcMF in June was significantly higher than that in other months. Soil pH, rainfall, mean monthly temperature and effective nitrogen of soil influenced the composition of EcMF community in Korean pine forest, showing positive or negative correlations with the richness of the dominant genera. Rhizosphere soil fungi were another factor influencing the richness of some EcMF in root tips. Pochonia, Hyphodontia, Fusarium, Collembolispora, Clonostachys, Apodus and Amanita had linear correlation with EcMF in root tips. More than 85% of the EcMF genera in the root tips and rhizosphere soil were in common. Root EcMF community formation mainly depended on invasion and dispersion of fungi and plant selection because not all soil fungi were present in the root system.