Dynamic Expression Of Alternanthera Philoxeroides Epigenetic Regulatory Factors In Contracting Hydrological Habitats

Alternanthera philoxeroides is native to South America but has become one of the worst weeds in China. Previous studies have suggested that phenotypic plasticity contributes to its rapid adaptation to a wide range of habitats, and thus leads to its invasion in China. However, the mechanisms underlying the adaptive phenotypic variation of A. philoxeroides remain unclear. Phenotypic plasticity refers to the ability of species to generate different phenotypes in different environments. Phenotypically plastic responses usually take place by altering gene expression. There is increasing evidence that epigenetic mechanisms e.g. DNA methylation allow organisms to respond to the environment through changes in gene expression.In this research, dynamic expression patterns of different epigenetic regulatory factors in A. philoxeroides growing in contracting hydrological habitats were detected using quantitative real-time PCR (qRT-PCR), bisulfite sequencing and high-throughput sequencing methods. The results showed that almost all 16 genes responsible for DNA and histone methylation were differentially expressed under different water treatments, and most of them were up-regulated in the early stages of water treatment. Bisulfite sequencing was employed to detect the methylation status of CpG islands within the promoter region of two genes, Contig942 and Contig23336 which were differentially expressed in response to different water treatments. It was found that some cytosines experienced fast and reversible changes in methylation status during water treatments, especially at asymmetric CHH sites. In addition,118 miRNAs were found to be differentially expressed in different habitats, and they can be grouped into 12 clusters based on their expression patterns.This work revealed the potential role of epigenetic regulatory factors in regulating the plastic responses of A. philoxeroide to environmental changes, providing useful information for understanding the molecular mechanisms underlying phenotypically plastic variation of A. philoxeroide in different habitats.