外来恶性杂草紫茎泽兰已入侵我国西南8省区，造成了严重的经济损失和生态灾难。研究发现其通过ICE1基因的去甲基化驱动了种群耐冷性的自然分化成功蔓延扩散，有持续向东北发达地区入侵的趋势，因此潜在着更大的风险。本项目基于紫茎泽兰耐冷性分化的表观遗传的前期基础立题，继续研究CBF冷响应转录途径中除ICE1基因外其他关键基因的甲基化差异及其时空表达模式，明确通路中受甲基化调节的其它关键基因；比较研究ICE1基因与SIZ1或(和) HOS1、SAL1/FRY1、CPL1/FRY2、SFR6基因在转录和表达水平的协同效应，揭示CBF转录途径的多基因表观遗传调节和基因甲基化互作机制；进一步通过研究紫茎泽兰杂交及套袋自交后代ICE1基因的甲基化位点遗传和变异，揭示耐冷通路的表观遗传及变异机制。充分阐明紫茎泽兰种群耐冷性分化多基因调控的表观遗传学机制，为预测紫茎泽兰的蔓延扩散范围和防治其入侵提供理论依据。

Crofton weed (Ageratina adenophora), a highly invasive alien plant, has invaded eight provinces through southwest China and consequently caused serious economic losses and ecological disasters. It was found that ICE1-demethylated drove continuous spreading the developed areas northeastward through cold tolerance evolution, which will lead to potential risk. Based on our previous discovery on epigenetics of cold-tolerance differentiation, we propose the present proposal to continuously study the difference in methylation level and space-time expression of other key genes, except ICE1, in CBF transcription pathway among different populations. The interaction of ICE1 with SIZ1, HOS1, SAL1/FRY1, CPL1/FRY2 and SFR6 genes will be comparatively studied in transcription and expression level. The main objectives are to reveal interaction mechanism of epigenetic and methylation in CBF pathway regulated by multiple genes. Furthermore, to verify the methylation variation and genetic mechanism, the methylation sites of ICE1 gene of the hybrids and self-pollinated progenies of crofton weed will be determined. Through these studies, we try to clarify that epigenetic mechanism of the cold tolerance evolution among Crofton weed populations derived by DNA methylation of multiple genes of CBF pathway. This will provide a theoretical basis for predication of the invasion range and prevention of crofton weed.