Population Genetic Diversity Of The Ectomycorrhizal Mushroom Lactarius Deliciosus From South China Based On Multiple Gene Genealogical

The multiple gene genealogical analyses is an effective method for population genetic research of microbiology, which has been widely used in fungal researches of population genetic biodiversity and the main mode of reproduction in natural populations. In this study, we analyzed the natural population genetic character of Lactarius deliciosus by multiple gene genealogical analyses method, and analyzed the genetic variation both within and among regional populations of L. deliciosus, and revealed the main mode of reproduction in natural populations of L. deliciosus. The results were showed as follows:(1) Four Tsong-jun samples, named CSUFTHH1,CSUFTHH2,CSUFTZJå'ŒCSUFTHY, assigned to the Lactarius sp.,Lactarius deliciosus,Lactarius akahatsu and Lactarius hatsudake, respectively based on internal transcribed spacer (ITS) sequence analysis and morphology character. And the identification result based on ITS sequence analysis and morphology of L. deliciosus collected from the pine forest of Hunan Porvince, is the first report.(2) We analyzed 68 samples of L. deliciosus from South China using ITS sequences. By comparing the difference of ITS sequences, to the haplotype diversity within each population, the relationships among local populations, the relationship between the level of genetic differentiation and geographical separation, and the contributions of local and regional geographical separations to the overall ITS haplotype variation were analysed. Our genetic analysis identified a total of 7 ITS haplotypes and these haplotypes were clustered into two distinct phylogenetic groups, and revealed two different phylogenetic directions. AMOVA test showed that there was significant genetic differentiation at both among local populations (16%) and within local populations (84%) levels, and p<0.01 for PhiPT. The Mantel test identified that the extent of genetic differentiation was significantly correlated with geographical distance, but this correlation was statistically insignificant. Our study revealed significant genetic divergence within L. deliciosus and detectable gene flow among geographical populations of this ectomycorrhizal mushroom, and the extent of genetic differentiation were correlated with geographical distance.(3) Using the right primers, we successfully obtained DNA sequences from three loci (the internal transcribed spacer region or ITS, the large subunit ribosomal RNA or LSU, and the mitochondrial small ribosomal subunit RNA gene or mtSSU rRNA), and we analyzed 83 isolates of the L. deliciosus from South China using these DNA sequences. Several lines of evidence suggest that recombination is the main mode of reproduction in natural populations of L. deliciosus. The PH test revealed that genealogies from all three genes are consistent with phylogenetic incompatibility (P<0.05). In linkage disequilibrium analyses, the alleles from the three analysed loci showed significant evidence of random association (IA=0.09657). Indeed, we found many evidence of phylogenetic incompatibility in this sample of L. deliciosus.