| Lentinula edodes is an important edible and medicinal fungus with a wide distribution range and one of the widely cultivated edible fungi,polysaccharides have anti-tumor,anti-aging,anti-oxidant,anti-bacterial,anti-viral and immune-regulating effects.Parental selection is a prerequisite for the success or failure of breeding and the screening of traditional high polysaccharide strains requires the determination of polysaccharide content after harvesting fruit bodies,which is often complicated and time-consuming.Therefore,studying the population genetics of important agronomic traits of Lentinula edodes,revealing the genetic background of the tested strains,providing a theoretical basis for subsequent parent selection and breeding of new varieties,and guiding pure line breeding theories.At the same time,the development of molecular markers closely linked to polysaccharide content genes for screening high polysaccharide strains can save labor and material resources,significantly improve the screening speed and breeding efficiency,and has important production practical value.In this study,Lentinula edodes strain "Huxiang F2" and one of its excellent selfed F2 generation strains "Shenxiang 1504" were used as experimental materials to collect spore monokaryons,identify their mating types,and then use the method of monospore selfing to construct F2 and F3 generation populations,conduct detailed statistical analysis on the spore monokaryons,cultivation,fruiting situation and important agronomic traits of F2 and F3 generation populations,compare the differences between the two populations,and study the differentiation of various traits,genetic law and correlation between traits.Simultaneously determine the fruit bodies polysaccharide content of F2 and F3 generation strains,compare the differences in polysaccharide content between two populations,locate sites related to polysaccharide content based on the BSA method,and develop In Del markers linked to polysaccharide content genes for screening of high and low polysaccharides strains.The main findings are as follows:(1)256 and 299 spore monokaryons of "Huxiang F2" and "Shenxiang 1504" strains were obtained through monospore isolation,and according to the number of four mating types of spore monokaryons,1028 and 972 self-mating pairs were designed respectively.In the F2 and F3 generation populations,in the pairing stage,15.47% and 23.56% of the paired combinations were unable to obtain binuclear strains due to the slow growth of mycelium,and F3 generation was significantly higher than that in F2 generation;during the production seed culture stage,the number of strains with bad traits was 7.78% and 9.57%;during the culture period of the rod,the number of strains with bad traits was 41.05% and 49.28%,and the proportion of strains with mycelium retreated in the F3 generation was significantly higher than that in F2 generation,the proportion of strains with non-colorized was significantly lower than that in F2 generation;during the fruiting stage,3.11% and4.32% of the strains did not bud,13.04% and 4.32% of the strains produced abnormal mushrooms,and 19.55% and 8.95% of the strains could produce normal mushrooms,and the proportion of strains producing normal fruiting bodies in F2 generation was significantly higher than that in F3 generation.In the spore monokaryons of "Huxiang F2" and "Shenxiang 1504",there were 29.69% and 60.20% of the spore monokaryons that hybrids obtained by multiple pairings did not grow or grow poorly on s PDA or on the culture material,did not turn color,did not bud,and produced abnormal fruiting bodies;there were 70.31% and 39.80% of the spore monokaryons that hybrids obtained by multiple pairings had normal fruiting bodies hybrids;there were 26 and 8spore monokaryons that hybrids obtained by multiple pairings had probability of producing normal fruiting bodies over 50%.(2)The average yield of single cultivated bag,average number of fruiting bodies per bag and average weight of single fruiting body of the two cultivated strains showed obvious differentiation.Compared with the F2 generation,the yield and number of fruiting bodies of the F3 generation showed partial deviation.The average yield of single cultivated bag of F3 was 43.84% lower than that of F2,and the average number of fruiting bodies per bag of F3 was 56.77% lower than that of F2.Compared with parent,33.83% of the F2 generation strains had higher yields than parent,and had high yield characteristics.Simultaneously,there was significant positive correlation between the color change state of rod and yield of single cultivated bag,yield of single cultivated bag had significant positive correlation with number of fruiting bodies per bag,and number of fruiting bodies per bag had significant negative correlation with weight of single fruiting body.(3)The polysaccharide content of F2 and F3 generation population strains both showed differentiation,and the degree of differentiation of the F3 generation was lower than that in F2 generation.At the same time,the polysaccharide content between two populations was normal distribution.12.04% of the strains in the F2 generation had higher polysaccharide content than their parents,showing a super-parent advantage in polysaccharide content.Based on mixed pool resequencing and comparison with reference genomes,7 sites related to polysaccharide content were located,located at 180000-766000 bp and 51600000-5190000 bp on chromosome2,26800-1977000 bp,2810000-3200000 bp on chromosome 4,40,000-970000 bp,1840000-2000000 bp and 2810000-3200000 bp on chromosome 7,and 47 In Del markers linked to polysaccharide content genes were developed in the candidate region.The above results analyzed the pairing of spore monokaryons of "Huxiang F2" and "Shenxiang 1504" and the cultivation and fruiting situation of F2 and F3 generations,and discussed genetic law and correlations of yield of single cultivated bag,number of fruiting bodies per bag and the weight of single fruit body in F2 and F3 generations.Candidate genomic regions related to the polysaccharide content were initially located,and the In Del marker linked to the polysaccharide content gene was developed.Subsequent studies can combine multiple populations to verify the closeness of the linkage between the developed molecular markers and gene of target trait. |
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