Diversity And Spatial Heterogeneity Of Arbuscular Mycorrhizal Fungi In The Rhizosphere Of Ammopiptanthus Nanus

Arbuscular mycorrhiza (AM) fungi are obligate symbiotic endophytes which widelydistributed in global terrestrial ecosystems and play a bridge role in the cycle of nutrientmaterial between plant and soil. It plays an important role in improving plant resistance,maintaining soil properties and repairing desert ecosystem.Ammopiptanthus nanus is a broad-leaved evergreen shrubs from leguminous family insand areas of Xinjiang, China and has important value in scientific, exploitage and utilization.Howere, The problems including seed propagation diddiculty, prone to pests, cutting of theplant for firewood lead to A. Nanus decreased year by year.For the research of A. Nanus was mainly focused on characteristics of plant communitystructure, Introduction and cultivation of A. Nanus and their symbiotic distribution of AMfungi of A. mongolicus activity, but diversity and spatial heterogeneity of AM fungicommunity in the rhizosphere of A. nanus reseach was rarely. To elucidate the speciesdiversity, spatial heterogeneity of AM fungi and the spatial dynamics of AM fungalcommunity under A.nanus by PCR-DGGE and DNA cloning and sequencing, we sampledfrom four different sites in Wuqia, Xinjiang in June2012. Soil samples were taken from therhizosphere of A.nanus and divided them into five depth intervals:0-10cm,10-20cm,20-30cm,30-40cm,40-50cm, respectively.1. Four genera and44species of AM fungi were isolated from the soil samples: Glomus,28species; Acaulospora,11species; and Scutellospora,4species; Gigaspora,1species. Ofthese, Glomus was the dominant genera;Glomus reticulatum was the common dominantspecies. The spore was characterized by its low density, small shape, thick wall and un-fulloverall shape, that indicated AM fungal spore had the obvious ecological adaptability.2. NS31/Glol domain sequences from AM fungi in the rhizosphere of A. nanus were usedto confirm optimum condition of DGGE. DGGE was performed on polyacrylamide gels withthe denaturing gradient from30%to60%and8%of concentration for Acrylamide,5uL PCRproducts were used for DGGE analysis. The electrophoresis was running at a fixed voltage of130V for8h at60℃. 3. The results showedthat the fingerprint characteristics of DGGE, richness, dominanceand diversity index of AM fungi have different from sampling sites and soil depths，amongthem,richness and diversity index of AM fungi were the highest at30-40cm soil layer inShang Artux.20AM fungal suquences belonged to two genern, such as Glomus andRhizophagus, and14species. Among them, G.indicum and Rh.intraradices were not relatedwith sequences of morphologically defined species.4. The results show that the Simpson’s diversity indice hadn’t significant difference at all;Species richness in Kangsu, Biaoertuokuoyi, Shang Artux increased successively and the thedifference was significant; Shannon diversity and evenness indices in Shang Artux werehigher than that at other sites; and the species composition of AM fungal inBaioertuokuoyi(yin) was the most similar to that in Shang Artux.5. Correlation analysis revealed that soil pH had a significantly positive correlation withspecies richness, Shannon diversity and evenness indices; Available P and total N had asignificantly negative correlation with species richness, Soluble salt had a significantlynegative correlation with Shannon diversity and evenness indices. The results supported theconclusion that species and genetic diversity and fungal community of AM fungi under A.Nanus in Xinjiang.