Molecular Genetic And Epigenetic Diversity And Genetic Structure Of Leymus Chinensis (Trin.) Tzvel. (Poaceae) Natural Populations Endemic To Songnen Plain

Genetic diversity and genetic structure of four Leymus chinensis (Trin.) Tzvel. (Poaceae) populations (with the same ecotype, Grey-Green Leaf), which comprised of a total of 48 clones collected from the Songnen plain in northeastern China were analyzed by amplified fragment length polymorphism (AFLP) and methylation-sensitive amplified polymorphism (MSAP) markers. The efficiency of the two markers was evaluated.Indices of genetic diversity, gene flow, genetic .distance, AMOVA, JSI analysis, the UPGMA cluster analysis and PCA generated from AFLP marker had the same trends. The spatial structure of the four populations was consistent with the stepping stone model. It can be envisioned that multiple other factors might have imposed their influence on the efficiency or effectiveness of gene flow among the L. chinensis populations. The CC population, as habitat fragmentation, was seen as being isolated due to its special predicament of its locality. Being in the midst of tall buildings seems to have raised a great barrier which is gradually isolating it from the rest. The exceptionally low level of gene flow between CL and CC populations provided a typical example to suggest that genetic isolation is not necessarily determined by geographical distance; instead, other factors could also have played a role in the differentiation of these populations although physical and/or biological isolation seem to be the most significant.In MSAP analysis, it was found that methylation pattern of L. chinensis populations in Songnen plain is characteristic of each population. The correlation between MSP (methylation-sensitive polymorphism) and MISP (methylation-insensitive polymorphism) influences and restricts each other, as a result, from Mental test of JSI matrices of them(r = 0.8370), they are likely affecting each other.Because JSI of AFLP is higher than that of MSP and MISP, the DNA methylation pattern change of L. chinensis is not only related to DNA sequence variation, but also likely being regulated by additional controlling system(s). The UPGMA cluster analysis and PCA from AFLP, MSP and MISP showed that a close link between the clones grown in the same abiotic conditions. Like CC was more closely related to BT (all grown at pH 7) and CL more closely linked to ZL which are grown in soils of pH 8.5-9.5. Thus, the possibility of habitat inducement can not be ruled out in causing heterogeneity in stressful conditions of varied salinity/alkaline which is known to cause heritable epigenetic variations in plants.