Epigenetic modification can change the pattern of gene expression without altering the underlying DNA sequence, which may be adaptive in clonal plant species. In this study, we used MSAP (methylation-sensitive amplification polymorphism) to examine epigenetic variation in Alternanthera philoxeroides, a clonal invasive species, in response to salinity stress. We found that salinity stress could significantly increase the level of epigenetic diversity within a population. This effect increased with increasing stress duration and was specific to particular genotypes. In addition, the epigenetic modification of young plants seems less sensitive to salinity than that of mature plants. This elevated epigenetic diversity in response to environmental stress may compensate for genetic impoverishment and contribute to evolutionary potential in clonal species.
Keywords: DNA methylation; alligator weed; developmental stage; salinity stress; treatment duration.