不同入侵地区黄顶菊DNA表观遗传多样性变化特征

从黄顶菊入侵的四个典型地区——邯郸市永年县(HDY)、沧州市献县(CZX)、衡水市衡水湖(HSH)和天津市静海县(TJJ)采集植物叶片,利用甲基化MSAP技术研究黄顶菊DNA表观遗传和多态性变化特征以及土壤环境因子与黄顶菊整体甲基化水平之间的相关性。结果表明:13对引物共扩增出993条MSAP条带,引物多态性百分比为88.52%。四个地区黄顶菊种群的多态性位点百分比较高,在84.03%~92.31%之间,遗传分化系数(G_(st))为0.07,只有7%的遗传变异存在于不同地区黄顶菊种群间,93%的遗传变异则存在于种群内,基因流(N_m)为3.321(1),表明四个不同入侵地区黄顶菊种群间存在广泛而频繁的基因交流。不同地区黄顶菊种群间遗传分化不显著,但甲基化模式差异显著,推测黄顶菊可能通过改变甲基化水平来维持自身对新环境的适应。MSP与MISP聚类结果表明TJJ与HDY亲缘关系最近,认为可能与两地土壤理化因子和所处地理位置相近有关,但相关性分析后发现黄顶菊甲基化水平与土壤因子之间的相关性并不显著(P0.01),推测地区环境对黄顶菊表观遗传多样性的影响是受多重因素共同作用的结果,而非某个单一因子的作用。

Studies on epigenetic diversity variation characteristics of Flaveria bidentis genome DNA of four different geographical distributions

We gathered Flaveria bidentis leaves from four typical invasion areas(HDY, CZX, HSH, and TJJ) and by MSAP method DNA epigenetic diversity and polymorphism variation characteristics as well as the correlation between soil environmental factors and Flaveria bidentis total methylation level were studied. The results showed that a total of 993 MSAP bands were amplified. There were 879 polymorphic loci in the total 993 bands and the percentage of which was 88.52%.The polymorphic loci percentage of Flaveria bidentis species in four different invasion area is higher which is between 84.03% and 92.31%. G_st is 0.07 and there were 7% genetic variations between four different Flaveria bidentis species and 93% of which were in species. N_m is 3.321(>1) which showed that there were extensive and frequent gene exchanges between Flaveria bidentis species. Genetic differentiation between populations was not significant, but there were significant differences in methylation patterns. We guess that the Flaveria bidentis may alter its methylation level to adapt to new environment. MSP and MISP clustering analysis showed that the relationship between TJJ and HDY was closest, which may be related to the soil factors and geographical position of two places. However, SPSS analysis showed that there were no significant correlation(P>0.01) between the methylation level and the soil factors. We speculate that the effect of environment to the epigenetic diversity of Flaveria bidentis was the results of multiple factors rather than a single factor.