Spatiotemporal Heterogeneity Of Arbuscular Mycorrhizal Fungi And Glomalin Under The Canopy Of Hedysarum Scoparium In The Northern Desert,China

The AM(arbuscular mycorrhizal)fungi belong to belong to the subphylum Glomeromycotina within the phylum Mucoromycota.They are soil beneficial microorganisms that can form symbiotic relationship with higher plant roots.AM fungi is a bridge connecting the above-ground ecosystem and underground ecosystems.It plays an important role in biomass production,material recycling,improving soil physical and chemical properties,stabilizing and rehabilitating ecosystems,and enhancing plant ecosystem productivity.Glomalin-related soil protein(GRSP)is a glycoprotein secreted by mycelia and spores of AMF that binds tightly to iron and promotes the formation and stabilization of soil clusters through "gluing",thereby enhancing soil stability to water and wind erosion and increasing carbon storage.Hedysarum scoparium is a pioneer species which can effectively prevent wind erosion and sand fixation of desertification in northwestern China.However,there are few studies on the arbuscular mycorrhizal resources.In this study,0-30 cm soil samples were collected from the rhizosphere of H.scoparium in Ordos,Dengkou,Wuhai,Alxa Left,Shapotou,Minqin and Anxi in the desert areas of northwestern China in 2015,2016 and 2017.Firstly,the high-throughput sequencing method was used to compare the community structure and diversity of AM fungi and their correlation with soil factors in 7 sites between July 2015 and July 2016.In addition,the contents of glomalin and its correlation with environmental factors in 2015,2016 and July 2017 in each site were examined.The objective of this study is to understand the utilization of the AM fungi resources in the desert ecosystem and provide a basis for the restoration of the ecosystem.The main results are as follows:1.A total of 51 AMF OTUs were obtained by high-throughput sequencing,including 5 orders,6 families and 7 genera,including Glomus,Diversispora,Funneliformis,Paraglomus,Claroideoglomus,Scutellospora and Archaeospora.Among them,Glomus has a total of 38 OUTs,the most dominant among all samples,and is the dominant genus of Wuhai,Alxa Left,Shapotou,Minqin and Anxi.Diversispora has a total of 5 OUTs,which is the dominant genera at Ordos and Dengkou.Diversispora celata is the dominant species in all samples.2.AMF Shannon-Wiener index were significantly different between two years at Wuhai,Alxa Left,Shapotou,Minqin and Anxi.AMF richness showed significant differences between years at Dengkou,Wuhai,Alxa Left,Minqin and Anxi.While the diversity index and richness of AMF Showed similarity at Ordos between July 2015 and July 2016.In 2015,Shannon-Wiener index,Chao1 and richness of AMF were significantly higher at Ordos and Alxa Left than these at other sites.In 2016,the The Shannon-Wiener index,and richness of AMF winners show higher values at Wuhai,Alxa Left,Shapotou and Minqin.As a result,excluding Ordos with large differences in soil types,the diversity and abundance of AMF showed a trend of increasing first and then decreasing from east to west in other sites.3.NMDS indicated that the communities of AMF were significantly separated by different years.Meanwhile,there were significant differences between the groups at Ordos and Anxi,Ordos and Minqin,Dengkou and Anxi,Dengkou and Minqin,while there was no significant difference in AMF community composition in Wuhai,Alax Left and Shapotou plots.4.Physical and chemical properties of soil were the main factors affecting the community structure of AM fungi.Besides,the content of glomalin and the contribution of glomalin to soil organic carbon were significantly different between years and sites due to changes in climatic conditions and soil physical and chemical properties.The results of AMF and soil factor correlation coefficient analysis showed that Shannon-Wiener index was positively correlated with ACP,EEG and TEG,and negatively correlated with soil pH.The richness of AMF is positively correlated with EEG and negatively correlated with SOC and soil pH.TEG was positively correlated with ALP and ACP,SOC and soil moisture.EEG was positively correlated with ALP,ACP and soil moisture.