蒙古沙冬青及其伴生植物AM真菌物种多样性

于2015年7月在内蒙古乌海、磴口2个样地选取蒙古沙冬青(Ammopiptanthus mongolicus)及其伴生植物为研究对象,分别采集0-20 cm和20-40 cm土层根围土样,利用高通量测序方法分析了不同植物AM真菌群落结构和物种多样性,发掘新物种,为补充和完善AM真菌分类体系提供依据。试验共分离鉴定3纲5目6科9属89个AM真菌OTU,属包括Glomus,Funneliformis,Diversispora,Claroideoglomus,Rhizophagus,Septoglomus,Scutellospora,Ambispora和Paraglomus。与形态学研究结果相比,高通量鉴定结果在属水平上更丰富。同一土层不同样地,蒙古沙冬青AM真菌丰度和多样性指数高于伴生植物;同一土层不同植物,AM真菌丰度和多样性指数表现为磴口高于乌海;同一植物不同样地,AM真菌ACE指数和Chao1指数20-40 cm土层高于0-20 cm土层,Simpson指数和Shannon指数0-20 cm土层高于20-40 cm土层。RDA分析表明,AM真菌ACE指数和Chao1指数与土壤碱解N显著正相关,与酸性磷酸酶显著负相关;Simpson指数和Shannon指数与碱性磷酸酶显著正相关,与pH显著负相关。结果表明,蒙古沙冬青AM真菌物种多样性高于伴生植物,同一样地,寄主植物与土壤深度共同作用对AM真菌群落组成有显著影响。

Species diversity of arbuscular mycorrhizal fungi in the rhizospheres of Ammopiptanthus mongolicus-associated plants

Ammopiptanthus mongolicus is an endangered broadleaf leguminous plant found in the desert ecosystem of northwest China, and it is also an excellent sand fixation plant. Zygophyllum xanthoxylum, Tetraena mongolica, Nitraria Tangutorum and Artemisia desterorum are plants that associated with A. mongolicus. These plants undergo competition inhibition and cooperative evolution, and are ideal for improving desert areas and preventing desertification. Arbuscular mycorrhizal (AM) fungi can form symbioses with most terrestrial plant roots, and play an important role in improving plant growth and maintaining ecosystem stability. In order to discover new species and complement and improve the classification system of AM fungi, we used high-throughput sequencing to study species composition and the ecological distribution of AM fungi in the rhizosphere of Ammopiptanthus mongolicus and associated plants. Eighty-nine operational taxonomic units of AM fungi belonging to 5 classes, 3 orders, 6 families, and 9 genera including Glomus, Funneliformis, Diversispora, Claroideoglomus, Rhizophagus, Septoglomus, Scutellospora, Ambispora, and Paraglomus were identified. With regard to quantification at the genus level, high throughput sequencing was more sensitive than morphological evaluation. Ammopiptanthus mongolicus had a greater richness and diversity index than other associated plants. The ACE and Chao1 indices of AM fungi were higher in the 20-40 cm soil layer than in the 0-20 cm layer. However, the Simpson and Shannon indices were higher in the 0-20 cm layer. AM fungal abundance and diversity index were higher in Dengkou site than in Wuhai site. Redundancy analysis showed that the ACE and Chao1 indices of AM fungi were significantly positively correlated with soil-available N, but negatively correlated with acid phosphatase. Simpson and Shannon indices were significantly positively correlated with alkaline phosphatase, and significantly negatively correlated with pH. Together, these data show that the species diversity of AM fungi was higher in Ammopiptanthus mongolicus than in its associated plants. Furthermore, they reveal that interactions of host plant and soil depth had a significant effect on the community composition of AM fungi.