Soil Fungal Structure And Diversity In Root Rot Occurrence Aeras Of Alfalfa(Medicago Sativa) In Northwest China

Alfalfa is the largest grown and most important pasture crop in China and the world.With the continuous expansion of planting scale,the root rot becoming the primary factors to restrict the alfalfa production,which have influenced the yield and quality of Alfalfa heavily.Revealing the soil microecological mechanism of occurrence of alfalfa root rot has important theoretical and practical significance for controlling the root rot and promoting sustainable development of alfalfa industry.In this study,high throughput sequencing technology was used to detect soil fungal diversity.And combined with edaphic factor,climate factor,geographical distance and altitude,this study preliminary explored the key driving factors affecting soil fungal diversity.The main findings are as follows:(1)Through the correlation analysis of environmental factors,this study found that the incidence of alfalfa root rot was related to soil moisture,phosphorus,potassium and cultivated years.Moreover,potassium can reduce the incidence of root rot.However,soil moisture and cultivated years will promote the root rot getting worse.(2)Through the study of soil fungal diversity,this study found that the dominant fungal phyla across all samples were Ascomycota,Mortierellomycota,Basidiomycota,Chytridiomycota.And the 10 frequently found genera(relative abundance>1%)were Mortierella,Chaetomium,Cladosporium,Alternaria,Gibberella,Fusarium,Penicillium,Verticillium,Tetracladium,Aspergillus.(3)Further analysis on the relationship between soil fungal diversity,environment factors,geographical distance and altitude showed that soil moisture among edaphic factor plays a predominant role in shaping soil fungal diversity.Potassium and soil texture also were significantly and positively correlated with soil fungal diversity.The result of this study proved that climate factors,geographical distance and altitude were another important predictor of soil fungal diversity.Such as MAP and altitude were the best predictor of soil fungal diversity.(4)To explained the phenomenon of Soil microbial biogeography,this study explored the relative importance of environmental factors and geographical distance factors to the soil fungal diversity.Environmental factors and geographical distance factors explained 25.3%and 1% of the variation of soil fungal communities.Thus,compared with relative importance of geographical distance factors,this study discovered that environmental factors were considered as a more important driver of soil fungal diversity at regional scale.In other words,this study indicating that dispersal limitation might be less important than contemporary environmental conditions instructuring fungal communities at regional scale.