Analysis Of The Molecular Basis Of Phenotypic Variation And Rice Blast Resistance In Asian Weedy Rice

Weedy rice has excellent phenotypic traits and strong variability,and has outstanding disease resistance and adaptability to adverse environments.It is a high-quality gene bank for rice variety improvement.In this study,175 weedy rice resources collected in different countries in Asia and some Americas were used as experimental materials to identify the phenotypic variation of weedy rice agronomic traits and the resistance to rice blast at the seedling stage.GSR 40 K rice high-density genome-wide SNP chip was used to analyze the genome genetic differences and related functional genes of rice blast resistance resources.The 56 K rice SNP chip was used to detect the polymorphism of the whole genome SNP site,and the phenotypic data related to the rice blast resistance of the test material was combined with the SNP genotype data to conduct a gene-wide association analysis,and to discover the Asian weedy rice resource rice Leaf blast resistance-related loci and candidate genes for functional annotation of blast seedling stage.The main conclusions are as follows:1.The results of the phenotypic variation analysis of the main agronomic traits of weedy rice show that the tested materials have a wide variety of agronomic traits,with obvious differences,and are excellent germplasm resource materials.The variation coefficients of the 12 measured agronomic traits are distributed between 14.0-121.8%,showing a large variation range and rich genetic diversity.Correlation analysis shows that there is a significant correlation between the appearance quality traits and yield traits of weedy rice,and its unique peel color has a very significant positive correlation with the spike seed setting rate,the correlation coefficient R is 0.213,and the awn length,awn color and Thousand-grain weight showed a very significant positive correlation,and the correlation coefficients R were 0.304 and 0.322,respectively.2.Through the detection and analysis of 56 K rice SNP chips,32,199 core SNP sites were screened out,with a total of 4,540,059 high-quality SNP markers,and the molecular fingerprint of Asian weedy rice resources was drawn.3.The results of population genetic structure analysis are clearly consistent with the phylogenetic tree and principal component analysis results of Asian weedy rice resources.The weedy rice resource populations collected in China have rich genetic diversity and a large range of variation.There are complex and frequent gene exchanges between weedy rice populations from different countries,which are potential high-quality germplasm resources.It provides an important material basis and theoretical basis for rice blast resistance breeding and variety improvement.4.Through genome-wide association analysis,a SNP locus located on chromosome12 that is significantly related to the resistance traits of rice blast seedling leaf blast in Asian weedy rice resources was located,and associated within the LD block where the locus was located To 14 SNP sites,13 candidate genes were annotated.5.The identification results of leaf blast resistance to rice blast at the seedling stage show that weedy rice resources with resistance level above medium resistance are abundant,accounting for 40.6%.Among them,there are 33 materials with resistance level,which come from Laos,China,South Korea,India,and Brazil accounted for 18.8% of the tested materials;the overall resistance performance of the tested materials was better,and the number of weedy rice resources collected in China was the largest and the average resistance was higher.Among them,Cambodia31,Cambodia37,and Cambodia42 were all Contains 4 rice blast resistance genes Pi5,Pid3,Pigm,and Pita;Cambodian weedy rice resources highly resistant to rice blast are indica-japonica intermediate type,high in homozygosity,and carry other excellent disease resistance reverse genes at the same time,which is a good choice for disease resistance breeding Potential genetic resources.This study provides a new perspective for the exploration and utilization of weedy rice resources.Combining genome and phenome association analysis,this study clarified the main agronomic phenotypic variation of the rich weedy rice resources in different geographical distributions in Asia,successfully constructed the molecular fingerprint of Asian weedy rice resources,and systematically analyzed the characteristics of Asian weedy rice resources.Population genetic structure,explore the genetic evolution trend of Asian weedy rice resources,screen out the SNP molecular markers related to disease resistance and stress for rice breeding and weedy rice resources,the research results will help reveal the Asian weedy rice resources The molecular mechanism of blast resistance formation,the discovery of key gene loci(SNP markers)that have important contributions to rice blast resistance breeding,further promote the development and utilization of beneficial resources of weedy rice,and provide new ideas for the exploration and utilization of weedy rice resources,laying the foundation for the molecular design breeding of rice blast resistant varieties.