ABI5蛋白是ABA信号转导途径中的关键转录因子之一，参与调控ABA抑制的种子萌发及萌发后生长发育过程。鉴定ABI5的互作蛋白，并阐明它们对ABI5的调控功能，对于深入理解ABI5调控的信号通路具有重要的意义。在前期研究中我们发现VQ家族蛋白VQ18和VQ26能与ABI5相互作用形成转录复合物。VQ18和VQ26主要在种子中表达，并负调控ABA介导的种子萌发过程。为了深入研究ABI5-VQ转录复合物调控ABA信号通路的分子机制，本项目将采用分子生物学、遗传学及生物化学的方法手段，系统分析VQ18和VQ26调控ABA反应的生物学功能，揭示它们与ABI5之间的遗传关系，并详细阐明它们对ABI5转录活性、DNA结合能力或蛋白稳定性的调控功能（即阐明它们调控ABI5的分子机制）。本项目的研究结果不仅有助于人们全面解析ABI5调控ABA反应的信号网络，还将有助于人们综合认识VQ家族成员的生物学功能。

ABI5 transcription factor, a crucial regulator of ABA signaling, positively modulates ABA-inhibited seed germination and early seedling growth. Identifying potential interacting partners of ABI5 and further elucidating biological consequences of those physical interactions will enhance our understanding of ABA signaling. Recently, we found that two VQ proteins, VQ18 and VQ26, physically interact with ABI5. VQ18 and VQ26 were predominantly expressed in dry seeds and strongly induced by ABA treatment. Phenotypic analysis showed that decreasing the expression of VQ18 and VQ26 simultaneously rendered plants hypersensitive to ABA during seed germination, indicating that VQ18 and VQ26 negatively regulate ABA-repressed seed germination. These results suggest that VQ18 and VQ26 proteins may be directly involved in ABA signaling through physically interacting with ABI5 transcription factor. To further test this possibility, we will undertake molecular and genetic approaches in this project to further clarify the roles of VQ18 and VQ26 in mediating ABA responses. To determine whether VQ18 and VQ26 genetically interact with ABI5, we are planning to generate abi5 vq18 vq26 triple mutant plants through crossing and examine their performances in response to ABA during seed germination. Moreover, we will investigate whether VQ18 and VQ26 affect the transcriptional function, DNA-binding activity, and/or degradation of ABI5. Our study not only contributes to explore the molecular mechanisms of ABI5-mediated ABA signaling, but also helps understand the biological functions of VQ proteins in regulating physiological processes.