[Variation analysis of genomic methylation induced by high temperature stress in Pinellia ternata]

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.