Analysis Of The Genetic Diversity Within And Between The Leymus Chinensis (Trin.) Tzvel. (Poaceae) Population Revealed By AFLP Marker

Although the plant molecular ecology has just developed, it has become a hot international ecological research field at present. The domestic scientists have accomplished the systematic researches about wild soybean (Glycine soja), Pinus koraiensis and Betula platyphylla. Meanwhile, as for the genetic differentiation of natural Leymus chinensis populations, they have also completed deep research works about its genetic germplasm resources. However, there is till rare reports about the extent, pattern and underlying mechanism of genetic differentiation within and between the phenotypic populations of Leymus chinensis. Most of the previous works only concentrated on utilizing morphological, physiological, and macroscopic ecology to fulfill the above goals.The extent and pattern of genetic differentiation between two naturally occurring phenotypes, grey-green leaf (GGL) and yellow-green leaf (YGL), of Leymus chinensis (Trin.) Tzvel., which colonize distinct habitats in the Songnen Prairie in northeast China, were investigated by amplified fragment length polymorphism (AFLP) analysis. Twelve selected AFLP primer pairs amplified 593 reproducible bands, of which 148 (24.96%) were polymorphic among 69 individuals taken from three populations: two natural ones (YGL and GGL1) and one transplanted (GGL2). Cluster analysis based on the AFLP data categorized the plants into distinct groups that are in line with their phenotypes and population origins, thus denoting clear genetic differentiation between the two phenotypes. This, together with their adaption to contrasting natural habitats, suggests that the two phenotypes probably represent stabilized ecotypes. The grouping was supported by multiple statistical analysis including Mantel's test, principal coordinate analysis (PCOORDA), and analysis of molecular variance (AMOVA). The GGL phenotype harbors a higher level of within-population genetic diversity than YGL, possibly reflecting selection by habitat heterogeneity. Although GGL2 is largely similar to its original population (GGL1), further diversification since transplantation was evident.Sequence analysis of a subset of phenotype-specific or phenotype-enriched AFLP bands implicated diverse biological functions (such as cellular genes, stress responsive genes and homologous retro-elements) being involved in ecological adaptation and final formation of the two phenotypes.Through the detail analysis and discussion about the experiment results, we got the possible mechanism underlying the ecological adaptation of different phenotypic Leymus chinensis populations and also approach the stability of the different leaf-color phenotypes, which provide some theoretical base for its future transplantation.