Effect Of Sulfur On Microbial Diversity And Ulcer Disease In Kiwifruit Orchard Soil

Kiwifruit canker disease is a devastating disease in the production of kiwifruit.The occurrence of this disease severely restricted the sustainable development of kiwifruit industry in Guizhou.In order to understand the effects of sulfur on microbial diversity in kiwifruit orchard soil and incidence of kiwifruit canke,in this study,soil bacterial and fungal community diversity and soil physicochemical properties of kiwifruit orchard in Xiwen,Guizhou Province were studied by Miseq high-throughput sequencing method.The effects of sulfur on the ultrastructure of kiwifruit plant stem and the occurrence of kiwifruit canker disease were also investigated.The main findings are as follows:(1)The application of sulfur treatment had little effect on the diversity of soil bacterial communities,but it could increase the bacterial richness.When the sulfur concentration was 2.5 kg/m~3,the bacterial richness was the highest.Sulfur application could inhibit the bacterium of kiwifruit canker.The growth of proteobacteria bacteria was not the best when the application concentrations of sulfur were 2.0 and 2.5 kg/m~3,the proportion of f proteobacteria bacteria community in soil was reduced by 6.9%and11.23%compared with the control group,respectively.(2)Sulfur application inhibited the diversity and abundance of soil fungal communities in the early experimental period(0~6 months).The inhibitory effect was obvious when the sulfur concentrations were 0.5 and 1.0 kg/m~3.After one year of sulfur application,the inhibition of fungal amount gradually decreased.(3)The application of sulfur treatment could affect the community structure of soil microorganisms.Cluster analysis showed that the community structure of soil bacteria and fungi changed after sulfur treatment.(4)Applying appropriate amount of sulfur could significantly improve the soil environment and increase the soil fertility in a certain period of time.When the concentration of sulfur was 1.5 kg/m~3,the soil fertility index was improved compared to the non-sulfur treatment,and the differences were significant.The improvement of the physical and chemical properties of soil was conducive to improving the resistance of kiwifruit plants to kiwifruit canker disease.(5)Appropriate application of sulfur had an important role in maintaining epidermal cells and chloroplast structure of kiwifruit plant stems.Under the condtion of 0.5 and 1.0 kg/m~3 sulphur treatment,the kiwifruit leaves had uniform cell size,closely arranged and tightly packed,and the thylakoid structure was complete and orderly.When the sulfur concentration exceeded 2.5 kg/m~3,the chloroplast ultrastructure of kiwifruit leaves was destroyed.(6)Because the number of bacteria in the proteobacteria was significantly reduced and the physical and chemical properties of soil were improved,the incidence of the kiwifruit canker disease was significantly decreased after kiwifruit orchard soil by sulfur treatment.The incidence of kiwifruit canker disease treated by 0.5~3.0 kg/m~3was less than 70%.When the amount of sulfur applied was 1.5 kg/m~3,the prevention and control effect was the best with the control effect of 58.82%.