| Lentinula edodes is the second largest edible fungus inferior to Agaricus bisporus in the world.L.edodes is pivotal in mushroom industry in China.China has vast territory and posess extremely rich wild L.edodes germplasm,which provides the possibility for L.edodes breeding and for mining resistance variation.Most agronomic traits of L.edodes are quantitave traits controlled by micro-effect polygene,and are susceptible to environmental effects.Genetic improvement only through phenotypic characters is not satisfactory.However,the molecular marker-assisted selection via the whole gene association analysis can efficiently excavate the genetic loci related to agronomic traits and resistance traits,which can help analyze the genetic basis of traits and provide excellent germplasm for breeding.In this study,59 wild strains of L.edodes were used to determine 11 agronomic traits.One hundred and twenty-six strains including 96 wild strains and 30 cultivars,were used to analyze three resistant traits.Based on high-density SNP markers by using whole genome resequenceing,genome-wide association study(GWAS)was performed.The main results are as follows:The yield-related traits showed a high coefficient of variation(CV)in cultivation experiments of two consecutive years.In the yield-related traits,the CVs of total weight of fruiting bodies per bag(Y),number of fruiting bodies(NF),and weight of a single fruiting body(WF)were 81.13%,89.42% and 70.57% respectively.The CVs of precocity-related traits were next to those in yield-related traits.The CVs of fruiting body shape-related traits ranged from 16.77% to 71.11%.The correlation analysis showed that there was a significant positive correlation between the fruiting body shape-related traits,and there was a significantly positive correlation between total weight of fruiting bodies per bag(Y)and NF.There were significantly negative correlation between the precocity-related traits and Y,between pilus diameter(PD)and pilus thickness(PT).Except for NF,the phenotypic values of the remaining ten agronomic traits showed a significantly positive correlation in two years.For the yield-related traits and the fruiting body shape-related traits,the interaction between genotype and year had a significant effect on the phenotype.The CVs of mycelia resistance to arsenic,cadmium and high temperature were 49.53%,22.58% and 31.64%,respectively.The resistance coefficient of arsenic,cadmium and high temperature were 49.53%,22.58% and 31.64% respectively.The correlation analysis showed that there was no significant correlation between resistences to arsenic,cadmium and high temperature.There was a significant difference in resistance to cadmium between the wild strains and the cultivated strain.The GWAS of 59 wild strains was carried out based on the high-density SNP markers developed by genome resequencing.The results showed that 861 SNP markers were associated to agronomic traits in two years' s fruiting experiments.In 2014,there were 196 SNPs significantly associated with NF,133 SNPs significantly associated with WF,31 SNPs with PW,and one with stipe diameter(SD).There were three SNPs associated with NF and Y.In 2015,there were 280 SNPs significantly associated with WF,158 SNPs significantly associated with stipe weight(SW),46 ones with PW,27 ones with the time interval from incubation to harvest of the first fruiting body(FB),24 one with the time interval from incubation to formation of the first primordium(FP),five one with stipe length(SL),three with Y.Among those SNPs,21 loci were significantly correlated with FB and FP,and 24 loci were significantly correlated with PW and PT.One SNP was significantly correlated with PW,SW and WF.A SNP was found to be significantly associated with mycelia resistance to arsenic in the GWAS of 126 strains.However,no candidate genes were found in the inkage disequilibrium(LD)decay distance.Two hundred and six SNPs were detected to besignificantly associated with resistance to cadmium.There was no SNP associated with resistance to high temperature.A total of 291 candidate genes associated with agronomic traits were found in the both years,and 39 candidate genes were involved in the mycelia resistance to cadmium.The result of Blast2 go indicated that those candidate genes are mainly related to the molecular functions of ions,small molecules,organic cyclic compounds and proteins,transport enzymes,hydrolases and oxidoreductase activities.The biological process these candidate genes involved are metabolic regulation,cell cycle regulation,decomposition of organic matter,response to stress,cell composition synthesis. |
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