不同种系百合鳞茎春化作用的分子调控机制研究

The annual production of important commodity flower cut lily is achieved by adjusting the sowing time of lily bulbs. Lily bulbs require long-term frozen storage, while the vernalization will need to be gone through the process of lily bulbs floral induction. Not only the Lily bulb vernalization plays a decisive role in flower formation, but also affect the flowering time and flowering quality. However, the molecular regulation mechanism of lily bulb vernalization and flowering transition process is still not very clear. Different vernalization treatments will be carried out to the most important three lily hybrids,including Asiatic hybrid lily, Oriental hybrid lily and Easter lily(Lilium longiflorum) bulbs. According to the different treatments to identify the genes related to vernalization process via differential expression in the candidate genes. To construct the subtractions libraries, and apply the cDNA-AFLP analysis to detect the gene expression in the lily bulb meristem tissue in different treatment conditions. The cloned sequences will be analyzed by using the database annotation. The genes related to flowering formation will be found via homologous sequence alignment in these sequences. The function of vernalization genes would be verified.Further studies will be carried out to the lily bulb vernalization gene response to low temperature signal and flower induction pathway, as well as regulation of the vernalization gene transcription level, translation level and post-translational level, and ultimately the common molecular regulation mechanism of different hybrid lily bulbs vernalization would be revealed.

重要商品花卉百合切花的周年生产是通过调整百合种球的播种期实现的。百合种球则需要长期冻藏，而春化是百合鳞茎必需要经过的成花诱导过程。春化作用不仅对成花起着决定性作用，而且也是影响开花时间和开花质量的重要因子。然而百合鳞茎春化作用和成花转变过程的分子调控机理仍不十分清楚。对百合最重要的三大种系亚洲百合、东方百合和麝香百合进行不同低温春化处理。根据不同处理中基因的差别表达来鉴别百合春化作用过程中涉及到的候选基因。构建差显文库并进行cDNA-AFLP分析来检测春化处理中百合鳞茎分生组织中基因的不同表达，应用数据库注释(annotations databases)来分析克隆序列获得百合春化基因，并对其功能进行验证。进而研究百合鳞茎春化基因响应低温信号和诱导成花的路径,以及春化基因在转录水平、翻译水平和翻译后水平上的调控，最终揭示不同种系百合鳞茎春化作用具有共性的分子调控机制。

项目的背景和科学意义：不同种系百合鳞茎解除休眠感受不同的低温信号，百合鳞茎在感受这一外界信号后,外界温度信号与鳞茎内部信号分子呼应，启动成花基因，最终完成百合鳞茎春化过程。主要研究内容是：本课题以百合鳞茎为试验材料，通过对3个种系（亚洲百合、东方百合、麝香百合）百合品种进行周年种植和形态观察，探明不同种系百合花芽分化类型，确定不同种系百合鳞茎生长发育模式，探究影响花芽分化的分子机理。重要结果和关键数据：东方百合‘索邦’内层鳞片中的可溶性糖含量变化作为监测百合低温春化完成的标志。鳞片中的IAA与ABA发生剧烈变化，而GA变化不显著；差异表达的不同蛋白相互作用，共同参与植物体内复杂的生理生化过程，从而诱导百合在在低温诱导下顺利通过春化，进而现蕾开花；运用RACE技术成功克隆了东方百合‘索邦’春化过程中的两个基因LoVRN1和LoSVP，并通过拟南芥转基因技术发现，LoSVP在百合响应低温诱导春化过程中具有抑制作用，可以延迟百合开花，而相反，LoVRN1基因可以促进百合提前开花。并且，LoVRN1基因在百合花型的改变上还有一定的作用；通过转录测序，获得亚洲百合‘Tiny ghost’冷藏处理组52,277,184条原始序列，差异表达基因为7,301条，进行 Unigenes 功能注释，对测序获得的春化成花相关基因VRN2，AP2，SOC1，LFY，AP1，AP2，AG，AGL的表达进行了分析；LA系百合‘耀眼’是麝香百合与亚洲百合的杂交品种，通过外施赤霉素处理的样本进行高通量测序来探索百合中其他成花诱导途径——赤霉素成花诱导途径的机制。获得高通量测序数据后，进行COG、GO和KEGG聚类。筛选与赤霉素信号响应和转导相关的基因序列作热图。基于转录组数据获得的DEGs，通过MCL算法将基因聚类到不同的模块中，获得关键功能基因，揭示麝香百合打破休眠诱导成花的分子机制。