脱落酸调控木薯MeASR3基因表达的分子机制研究

Cassava is a typical drought-tolerant crop. Abscisic acid signaling plays an important role in modulating the strong drought tolerance of cassava. Abscisic acid，stress，and ripening induced protein (ASR) is a crucial responsive factor of ABA signaling, which functions on improving plants tolerance to drought stress. However, it is unclear how ABA signaling modulates ASR gene expression, and hence improving plants tolerance to drought stress. Previously, we found that ABA signaling can induce the expression levels and promoter activity of MeASR3 gene, resulting in the improved tolerance to drought stress. Based on these results, we speculate that transcriptional modulation is crucial for ABA inducing the expression of MeASR3 gene. In this study, we will characterize the ABA responsive element in the promoter region of MeASR3 gene and their interactive transcription factors, study the roles and mechanisms involved in transcription factors modulating MeASR3, and elucidate the molecular mechanism underlying ABA modulating the expression of MeASR3 gene. This work will be benefit for improving the understanding of ABA signaling transduction pathways and the molecular mechanism of cassava responding to drought stress, and supply theoretical evidence for study on drought-tolerant mechanisms and drought tolerance improvement in cassava and other crops.

木薯是一种典型的耐旱作物。脱落酸(ABA)信号在调控木薯特殊耐旱性上起着重要作用。脱落酸胁迫成熟响应蛋白(ASR)是ABA信号途径的关键应答因子，并且能够显著提高植物的耐旱性。但是，ABA信号如何调控ASR基因的表达，从而增强植物的耐旱性尚不清楚。我们前期的研究发现ABA信号诱导木薯MeASR3基因的表达和MeASR3基因启动子活力，进而增强植株的耐旱性。因此，我们推测转录调控是ABA信号诱导MeASR3基因表达的关键途径。本项目采用生物化学与分子生物学研究方法，鉴定MeASR3基因启动子上的ABA应答元件和与其互作的转录因子，研究ABA应答转录因子对MeASR3基因的调控作用及调控机理，以期阐明ABA调控木薯MeASR3基因表达的分子机制。研究结果将拓展对ABA信号转导途径的认识和木薯应答干旱胁迫的分子机理的理解，为木薯及其它作物抗旱机理的研究和抗旱性遗传改良提供理论依据。

木薯具有耐旱的生物学特性，是一种典型的耐旱作物。ABA生物合成及信号转导在调控木薯特殊耐旱性上起着重要作用。但是，ABA信号如何调控木薯特殊的耐旱性仍然是有待解决的问题。这一问题的解决还取决于对ABA信号途径关键应答因子作用机制和调控机制的深入研究。. 脱落酸-，胁迫-，成熟-响应基因(Abscisic acid-，stress-，and ripening-induced gene, ASR)是ABA信号途径的一个关键应答因子，并且能够显著提高植物的耐旱性。但是，ABA信号如何调控ASR基因的表达，从而提高植物抗旱性尚不清楚。解决这一问题的重要途径是从DNA与蛋白质相互作用的角度解析ABA信号调控ASR基因表达的分子机制，并最终能够阐明哪些ABA应答转录因子与ASR基因的启动子上ABA应答元件结合调控ASR基因的表达，提高植物的耐旱性。. 本项目组通过系统分析木薯基因组测序数据发现木薯中存在五个ASR成员 (MeASR1-5)。进一步研究表明ABA信号诱导了MeASR3基因的表达和MeASR3基因启动子活力，从而增强了植株的耐旱能力。因此，我们推测转录调控是ABA信号诱导MeASR3基因表达的关键途径，但具体分子机制不清楚。本项目采用生物化学与分子生物学研究方法，鉴定MeASR3基因启动子上的ABA应答元件和与其互作的转录因子，研究ABA应答转录因子对MeASR3基因的调控作用及调控机理，以期阐明ABA调控木薯MeASR3基因表达的分子机制。研究结果将拓展对ABA信号转导途径的认识和木薯应答干旱胁迫的分子机理的理解，为木薯及其它作物抗旱机理的研究和抗旱性遗传改良提供理论依据。