Study On Genetic Diversity And Response And Adaptive Evolution To Temperature Of Lentinula Edodes Cultivars

Lentinula edodes（Berk.）Pegler is the second largest cultivated edible fungus in the world.It has important edible and economic value for human beings.It is also a model strain for the genetic research of edible fungi.L.edodes belongs to medium low temperature and variable temperature fruiting fungi,and the required temperature is determined by the strain of shiitake.Temperature has become a limiting factor affecting the growth and quality of L.edodes,but the genetic background of the difference in temperature type of L.edodes cultivars is not clear.In addition,the genetic background of temperature type differences in shiitake cultivars is unclear.In order to reveal the genetic background of the germplasm resources of the L.edodes cultivars and their response and adaptive mode under cold and heat stress,the molecular ecology method was used to study some cultivars of L.edodes.The main research results are as follows:1.33 L.edodes cultivars from 8 provinces and cities were identified by confrontation and antagonism test and r DNA its molecular marker technology.It was preliminarily judged that L.edodes cultivars 18-1 and liaoxiang 6,Jixiang 1 and Lingyuan species,Lingxian 1 and168,Guangxiang 2044 and L26 may have the phenomenon of"same substance and different name".The results of phylogenetic analysis showed that these cultivated varieties with close genetic distance were similar in temperature response mode.2.By using Illumina novaseq 6000 platform to resequence 40 germplasm,a total of51.26 Gbp data and 425,215 high-quality SNP variation sites were obtained.Based on population structure analysis,L.edodes cultivars can be finally divided into two subgroups.Subgroup 2 is low temperature cultivar 241-4.In subgroup 1,a group of"same substance and different name"cultivated strains were identified,namely Xiaxiang 2 and 130.Through genetic diversity analysis showed that the nucleotide diversity in L.edodes population was low,indicating that the cultivated population of L.edodes was highly selected;The large genetic differentiation index among populations indicates that Chinese L.edodes cultivars are rich in genetic diversity,and the materials taken this time are representative.Xiaxiang 2 and241-4 have the greatest differentiation.Selection based on F_ST,θπand Tajima’s D reveals the enrichment of genes involved in environmental adaptation.Therefore,39 positively selected genes were identified,of which 6 are related to temperature regulation.Through the analysis of functional enrichment in the selected areas,it is found that the pathways of significant enrichment are mainly significantly related to environmental variables.3.Verify the screened functional genes based on RT-q PCR technology,indicating that there were significant differences in the expression of 3 functional genes between high temperature cultivar Xiaxiang 2 and medium low temperature cultivar 241-4 under cold and heat stress（4℃,37℃）.The functional gene gene-HHX47＿DHR400862 was significantly up-regulated in cultivars（241-4）under low temperature treatment（4℃）.gene-HHX47＿DHR4001037 was significantly up-regulated in high temperature strain（Xiaxiang 2）and high temperature treatment（37℃）.gene-HHX47＿DHR8000247 showed ambiguous linear relationship in different cultivated cultivars and temperature stress,indicating that the adaptive evolution of L.edodes was affected by complex regulatory mechanisms except temperature environment.