拟南芥IQM5介导钙调素信号调控成花的功能解析

Flowering is very crucial for plants to reproduce and is regulated by both genetic and environmental cues. The flowering regulators consist of at least 6 closely interlinked but divergent genetic regulation pathways including photoperiod, gibberellin, vernalization, autonomous pathways, ambient temperature and age. To date 104 flowering-regulatary genes have been identified in Arabidopsis, however it is still not enough to fully reveal the molecular network for flowering regulation. Moreover, the research reports regarding the age pathway are still very limited. Ca2+/CaM signaling plays an important part in plants response to internal and external cues and regulates a variety of cell physiology, growth and development in plant. How the Ca2+/CaM signaling regulates the flowering time, however, is remained to be revealed. Our research showed that IQM5 contains an IQ motif and can bind with calmodulin 5 in yeast, and is probably involved in the age-pathway flowering regulation. To reveal the mechanisms underlying involvement of IQM5 in flowering regulation and set up a link between calmodulin signaling and plant flowering regulation, the functional complementation for iqm5 mutants, the CaM signaling mediated by IQM5, the molecular network for IQM5 to regulate flowering time, and RNAs bound by IQM5 will be studied. Our results will be helpful to fully understand the function of IQM5 and calmodulin, enrich the molecular network of flowering regulation as well as a comprehensive understanding function of Ca2+/CaM signal in plant development, and can offer reference for flowering-time-regulation breeding in plants.

成花是植物繁衍的关键环节，已知至少有104个基因涉及光周期、春化、赤霉素、自主、温度及年龄等6条成花调控遗传途径，但是仍不足以全面揭示相关的分子调控网络，且年龄途径的研究急待深入。钙/钙调素信号在植物生长发育和响应环境变化中发挥着重要作用，不过其如何参与成花调控鲜见报道。之前，我们发现IQM5能在酵母中通过所含有的IQ基序与钙调素结合，并可能参与年龄途径成花调控。本研究拟通过iqm5突变体的功能互补、IQM5介导的钙调素信号和参与成花调控途径及IQM5结合RNA的研究，解析IQM5参与成花调控的分子机理，建立钙调素信号参与成花调控的分子连接点。研究结果有助于理解IQM5和钙调素的功能、丰富成花调控的分子网络以及全面理解钙调素信号在植物发育中的作用，并可为植物花期调控提供参考。

成花是植物繁衍和生存的关键环节，已报道至少有280多个基因涉及光周期、春化、赤霉素、自主、 温度及年龄等6条成花调控遗传途径，但是仍不足以全面揭示相关的分子调控网络，且年龄途径的研究报道较少也不够深入。钙/钙调素信号在植物生长发育和对环境变化的响应中发挥着重要作用，不过其如何参与成花调控鲜见报道。之前，我们发现IQM5能在酵母中通过所含有的IQ基序与钙调素结合，并可能参与年龄途径成花调控。过去4年，为了阐明相关的分子机制，开展了IQM5介导的钙调素信号参与成花调控的进一步生理学、遗传学和分子生物学研究。得到如下主要结果：1）进一步提供了IQM5调控成花的分子遗传学证据；2）IQM5在体内外均能与钙调素结合，并介导钙调素信号调控成花；3）IQM5通过FLC参与年龄途径成花调控；4）确定了钙调素信号参与成花调控的分子连接点，初步建立了相关信号转导通路。本研究解析了IQM5参与成花调控的分子机理，的结果有助于全面理解IQM5和钙调素的功能、丰富年龄途径成花成花调控的分子网络以及全面理解钙调素信号在植物发育中的作用，并可为植物花期调控提供参考。