Diseases Resistance Analysis Of Kentucky Bluegrass Dwarf Mutant

Kentucky bluegrassis the most widely used lawn grass species in temperate regions of the world.In the early stage,the research group obtained the dwarf mutant A16 of precocious grass through space mutation breeding technology.In order to analyze its disease resistance,the Wild Type?WT?and dwarf mutant A16 of precocious grass were used as experimental materials in this study.Respectively inoculated Sclerotinia?the pathogen of Dollar spot disease?,Pythium aphanidermatum?the pathogen of pythium disease?,and Rhizoctonia?the pathogens of Brown patch?,the determination of WT and A16 under three kinds of pathogen infection incidence and disease index,activity of superoxide dismutase?SOD?,peroxidase?POD?activity and catalase?CAT?activity,ascorbic acid peroxidase?APX?activity,malondialdehyde?MDA?content,the contents of soluble sugar and soluble protein,as well as the expression levels of disease-related genes NPR1and PR1 at different time after infection,were used to compare the resistance of WT and A16 to infection by different pathogens and the resistance response to the same pathogen.The results showed that the indexes of WT and A16 were different under the infection of Sclerotinia.The incidence and disease index of WT in the apparent index were all significantly greater than A16,the SOD activity and soluble protein content of WT in the physiological index were not significantly different from that of A16,POD activity,CAT activity,APX activity and soluble sugar content were al lsignificantly less than A16,and MDA content was significantly greater than A16.The relative expression levels of both NPR1and PR1 genes of A16 reached the peak at 48h,which were 51.099 and 36.903.The disease indexes of WT and A16 were also different under the infection of Pythium aphanidermatum.The incidence of WT and disease index in the apparent disease indexes were significantly higher than that of A16,the activity of SOD,POD,CAT,APX and soluble sugar content in WT were all significantly lower than that of A16,and the content of MDA and soluble protein in WT were significantly higher than that of A16.The relative expression levels of NPR1 and PR1 gene of A16 both reached the peak at 24h,which were 7.434 and 8.723.The differences in the resistance responses of WT and A16 in the case of Rhizoctonia infection were as follows:the incidence and disease index of WT in the apparent index were both significantly less than A16.The activities of SOD,POD,CAT,APX and soluble sugar in WT were all significantly greater than A16,while the contents of MDA and soluble protein in WT were significantly less than A16.The relative expression of NPR1 and PR1 gene of A16 both reached the peak at 96h,which were 6.738 and 2.916.According to the apparent index,physiological index and molecular index,the resistance of A16 to Dollar spot disease and pythium disease was stronger than WT,and the resistance to brown spot disease was weaker than WT.When A16 was infected by three pathogens at the same time,its resistance was A16_pythium.