Study On Rhizosphere Microbial Flora Changes Potatoes Continuous Cropping Soil

This study focus on the fungal community diversity in potato monocropping soil of GanSu province, we analysised the soil fungal community and their variable roles in ecological functions based on conventional plate culturing and contemporary microbial molecular ecological methods (DGGE, clone library,454sequencing). Clone library research indicated that the rhizosphere microbial community changed during the years of potato continuous cropping, the Ascomycota became the major phylum. While from the454sequencing analysis, we found the dominant communities were similar, with dominant OTUs belonging to Hypocreales and Sordariale, but there was an obvious difference in higher-order organization (maybe the few). Research revealed that the number of co-expressed genes in healthy soil was more than in diseased, and connectivity of the same OTU in diseased soil was lower. Statistics revealed that the number of Fusarium solani was increased during different cropping years, and other pathogens were correlated significantly with others, positively or negatively. It was found that soil variables played an important role in soil functions. In diseased soil, soil properties were most significantly correlated with fungal populations negatively while healthy soil was balanced. Among them, the soil organic matter (OM) was the key variable associated with the healthy community, whereas NH4+-N and EC were the key variables associated with the diseased community. As NH4+-N and EC are directly combined with fertilizer amendment, it was concluded that the fertilizer amendment was the major cause leading to the community shifts from healthy to diseased one. Futher analyzing found some crossed fungal communities in healthy and diseased soil, soil properties would change the function of some fungal communities and their ecological functions as well as the soil planting condition with continuous cropping years.