| Lentinula edodes is the second most cultivated edible mushroom in terms of total world production and is one of the most important mushroom in the east Asia. China processes abundant natural germplasm resources of L.edodes due to a vast territory. These rich germplasm resources are the basis of breeding programme of L.edodes. The most of agronimic and economic traits of L.edodes were quantitative traits controlled by multi-gene and easily impacted by environment, which are difficult to be improvement by tradition breeding method. It is possible to utilize marker assisted selection (MAS) in L. edode with the rapid development of molecular marker techniques. But the study of QTL ofL.edodes was one the primary stage. There are a lot of problems to be solved right now. Association analysis, based on the linkage disequilibrium (LD), is the alternative method for studying on the quantitative trait and MAS of L. edodes.In this study, we collected94wild L.edodes strains from14provinces of china and analyzed using34SSR markers. And then genomic molecular marker scanning on the population was performed. Our objective was to determine the genetic diversity, to identify their population structure. At the end, basis on the molecular information, the molecular markers closely related to13traits were then determined by association analysis. The major results are as follows:1. In this study,94strains of L.edodes were evaluated for genetic diversity, principal coordinate analysis (PCA) and population structure using34SSR markers. The results showed that the34SSR primer pairs amplified a total of169alleles,162(95.9%) were polymorphic. The values of the expected heterozygosity (He), polymorphism information content (PIC) and Shannon’s information index (I) were0.44,0.4and0.89, respectively. The values of He, PIC and I indicated the existence of high genetic diversity in the L.edodes’ population. It is appropriate for association analysis. The94strains were divided into three main groups by STRUCTURE cluster, UPGMA cluster and principal coordinate analyses. There are the highly accordance among three methods.2. Linkage disequilibrium values were calculated for561pairwise comparisons among the34SSR loci. Among all loci pairs,150pairwise comparisons (26.74%) were in LD at the P<0.05level. The values of LD were all low with the range from0to0.2. Among linked locus pairs,67(44.67%of150,11.94%of561) pairs were in LD at the P<0.01level. Of all significant pairs, only3(0.53%of561) showed an r2value greater than0.2.3. Association analysis was calculated by general linear model (GLM) based on34SSR loci and13traits in software TASSEL2.0. Seven SSR loci were detected significant associated with five traits at the P<0.01level. Of which, three loci, ISO17、LEP2and X015, were significant associated with the mycelium growth rate in sawdust, whose phenotypic variation explaining rate were26.49%,16.59%and33.91%respectively and the total explaining rate was76.99%; One loci (LEN41) was significant associated with pileus diameter with17.04%explaining rate; One loci (LTY1) was significant associated with pileus thickness with31.65%explaining rate; One loci (F041) was significant associated with primordium forming period with9.9%explaining rate.4. Allels of loci significantly associated with the traits were analyzed further to discover typical materials with effective allels for the traits. The resut showed that X015-1was the best allel of positive effective for mycelium growth rate in sawdust, LEN41-1of positive effective for pileus diameter, LTY1-2of positive effective for pileus thickness, F041-1of negative effective for primordium forming period.The results of our study provide additional QTL information for marker assisted selection. |
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