Pathogen Identification,Genetic Diversity Analysis And Sensitivity Determination Of Shenzinomycin To Rice Sheath Blight In Three Provinces Of Northeast China

Rice sheath blight is one of the rice diseases that cause severe economic losses and a serious decline in rice yield and quality worldwide.As one of the main rice producing areas in China,the three provinces of northeast China have a wide range of rice sheath blight.Most of the main rice varieties in actual are susceptible,and the methods of disease control are highly dependent on the chemical.How to prevent rice sheath blight in environmentally-friendly is a prominent problem in rice production in the absence of resistant germplasm resources.Existing research shows that,in addition to Rhizoctonia solani,some fungi of the Rhizoctonia genus can also induce rice sheath blight.To ascertain the distribution and genetic structure,analyze the evolutionary trends of various taxa,and scientifically control rice sheath blight,samples of rice sheath blight were collected from13 major rice producing areas in the three provinces of northeast China in this study.After isolate and identify the samples,we measured the pathogenicity,the anastomosis group,and the sensitivity to Shenzinomycin of the pathogenic fungi.The genetic diversity of the pathogenic fungi was analyzed by 16 pairs of SRAP primers.The main results were as follows:?1?A total of 207 strains were isolated,including 176 R.solani strains?accounting for 85.02%?and 31 R.oryzae-sativae strains?accounting for 14.98%?.R.solani was isolated in all regions,but R.oryzae-sativae was isolated only in part regions of Heilongjiang Province and Liaoning Province.Therefore,R.solani was the dominant strain of rice sheath blight in three provinces in northeast China.?2?Except for three unknown strains,the dominant anastomosis group of R.solani in three provinces of northeast China is AG1-?A,accounting for 90.34%;the AG-4 group accounting for 6.81%;the AG1-1C group accounting for 1.14%The anastomosis group of R.solani strains has no obvious relationship with its geographical distribution.?3?The pathogenicity of R.solani strains is different.The medium pathogenicity strain is the dominant strain,accounting for 61.90%,and the pathogenicity of the strain is related to its geographical origin.The pathogenicity of R.oryzae-sativae strains is different.The medium pathogenicity strain is the dominant strain,accounting for 74.19%,and the pathogenicity of R.oryzae-sativae strains is not related to its geographical origin.There was no correlation between the pathogenicity of two strains and the results of UPGMA cluster analysis.?4?The UPGMA cluster analysis results of 176 R.solani strains are related to its geographical origin.The genetic diversity of R.solani populations in 13 locations is different.The genetic structure of the population in Jiamusi city of Heilongjiang province is relatively complicated,and the population in Songyuan city of Jilin province is relatively simple.Geographical distance of R.solani populations does not correlate with its genetic distance,genetic identity,gene flow,and gene differentiation coefficient.The population of R.solani in Songyuan city of Jilin province is special,which has the potential to become an independent population and greater genetic variation.The geographical distribution of R.solani population has a certain impact on the gene flow and gene differentiation of the entire population.The population of R.solani in each locations has geographical isolation in space.AMOVA analysis showed that the genetic variation of the R.solani populations mainly came from within the group.?5?The UPGMA cluster analysis results of 31 R.oryzae-sativae strains are related to its geographical origin.The genetic diversity of R.oryzae-sativae populations in five locations is different.The genetic structure of the population in Acheng district,Harbin city of Heilongjiang Province,is relatively complicated,and the population in Liaozhong district,Shenyang city of Liaoning Province,is relatively simple.Geographical distance of R.oryzae-sativae populations does not correlate with its genetic distance,genetic identity,gene flow,and gene differentiation coefficient.The geographical distance between two locations in Liaoning province is closest,but its genetic distance and genetic differentiation are great,along with the weak gene flow.The reason may be that the differences in soil and climatic conditions from two locations cause the strains to face different selection pressures,and their gene made the directional selection.The geographical distribution of R.oryzae-sativae population has a certain impact on the gene flow and gene differentiation of the entire population.The population of R.oryzae-sativae in each locations has geographical isolation in space.AMOVA analysis showed that the genetic variation of the R.oryzae-sativae populations mainly came from within the group.?6?The EC₅₀ values of R.solani strains form three provinces in northeast China to shenzinomycin ranged from 0.0487 to 0.2348?g/m L,and the baseline sensitivity is 0.1292?g/m L.All the strains of R.solani are sensitive.The EC₅₀ values of R.oryzae-sativae strains form three provinces in northeast China to Shenazinomycin ranged from 0.0517 to 0.1697?g/m L,and the baseline sensitivity is 0.1163?g/m L.All the strains of R.oryzae-sativae are sensitive.Shenazinomycin does not affect on the sclerotia germination of R.solani and R.oryzae-sativae.The susceptibility of R.solani and R.oryzae-sativae strains to Shenazinomycin does not correlate with the geographical origin,pathogenicity,and UPGMA cluster analysis results.