Genetic diversity and population structure of wild Lentinula edodes (Xianggu) germplasm resources in Changbai Mountain, China, based on ISSR markers

To screen high-quality strains and comprehensively exploit the superior traits of Xianggu or shiitake and their related species, a collection of strains from various locations was utilized. After the activation of these strains, genomic DNA was extracted, followed by inter simple sequence repeat (ISSR)-PCR, internal transcribed spacer (ITS) amplification, and sequence identification. The ISSR molecular marker was used to detect the polymorphism of 21 shiitake mushroom strains with 19 primers at the molecular level. ISSR analysis further verified the genetic diversity of the 21 germplasm strains. Specifically, the correlation coefficient r was determined to be 0.86399, the average number of alleles (Na) was 1.7158, the average effective number of alleles (Ne) was 1.4529, the average Nei's genetic diversity index was 0.2632, and the mean Shannon's information index was 0.3916. The genetic similarity coefficients of the 21 strains ranged from 0.4000 to 0.9417. The similarity coefficient between 73.04% of the strains was less than 0.7, indicating that there were large genetic differences between the strains. Through ISSR primer amplification, band pattern analysis, cluster analysis, assessment of the genetic similarity coefficient and genetic distance, and the establishment of DNA fingerprints, it was demonstrated that the 21 strains possessed rich genetic diversity. The findings indicated that the ISSR technique could serve as a valuable tool to assist breeding, significantly reducing the workload, and enhancing work efficiency, thereby making substantial contributions to the identification and breeding of shiitake mushroom strains.