Variation analysis of genomic methylation induced by high temperature stress in Pinellia ternata / 中国中药杂志

Pinellia ternata belongs to the Araceae family and is a medicinal herb. The tuber is the medicinal organ with antitussive, antiemetic and anti-tumor activities. It is easy to encounter high temperature environment during the growth periods, leading to decrease of tuber production. At present, the mechanism of response to high temperature stress in P. ternata is still unknown. DNA methylation plays a vital role in plant protection against adversity stress as a way of epigenetic regulation. In this study, P. ternata was used as material for treatment of high temperature stress at 0 h, 6 h and 80 h, and methylation sensitive amplification polymorphism(MSAP) analysis was conducted on the changes of DNA methylation in its genome. The results showed that 20 pairs of MSAP primers were selected from 100 MSAP primers with multiple clear and uniform bands, and 353, 355 and 342 loci were amplified from materials of P. ternata treated in the high temperature stress 0 h, 6 h and 80 h, respectively. Cytosine methylation levels of CCGG context in the above materials were characterized as 60.91%, 44.79% and 44.74%, respectively. And the full methylation ratios were 16.71%, 22.25% and 29.24, respectively. It demonstrated that high temperature stress significantly induced the down-regulation of DNA methylation level and up-regulation of the full methylation rate in P. ternata genome. This study provides a preliminary theoretical reference for analyzing the mechanism of P. ternata responding to high temperature stress from the epigenetic perspective.

Analysis of shading on DNA methylation by MSAP in Pinellia ternata / 中国中药杂志

Pinellia ternata is a medicinal herb of Araceae, and its tubers are used as medicines. It is a common Chinese herbal medicine in China and has a large market demand. When exposing to strong light intensity and high temperature during the growth process, P. ternata withers in a phenomenon known as "sprout tumble", which largely limits tuber production. Shade can effectively delay sprout tumble formation and increase its yield, however the relevant regulation mechanism is unclear. DNA methylation, as a self-modifying response to environmental changes, is often involved in the regulation of plant growth and development. In this study, P. ternata grown under natural light and 90% shading were selected as the control group and the experimental group for genomic DNA methylation analysis by using methylate sensitive amplification polymorphism(MSAP). The results showed that a total of 617 loci were detected with 20 pairs of primers, of which 311 were in the natural light group and 306 in the shading group. The methylation sites in the light and shading groups accounted for 58.2% and 71.57%, respectively, and the methylation ratios in the methylation sites were 27.65% and 29.41%, respectively, indicating that shading significantly induced the genome DNA methylation of P. ternata. Compared to the natural light group, shading promoted 32.51% of the genes methylation, while inducing 16.25% gene demethylation. This study reveals the DNA methylation variation of P. ternata under shading conditions, which lays a preliminary theoretical foundation for further analysis of the mechanism of shading regulation of P. ternata growth from epigenetic level.