背景回顾：The IDD transcription factors mediate various aspects of plant growth and development. We previously reported that an Arabidopsis IDD subfamily regulates spatial auxin accumulation and thus organ morphogenesis and gravitropic responses.

提出问题：However, its functions in stress responses are not well defined. 

主要发现：Here, we use a combination of physiological, biochemical, molecular, and genetic approaches to provide evidence that the IDD14 cooperates with bZIP-type binding factors/AREB-binding proteins (ABFs/AREBs) in ABA-mediated drought tolerance. 

结果1-IDD14基因正调控干旱耐受性：idd14-1D, a gain-of-function mutant of IDD14, exhibits decreased leaf water loss and improved drought tolerance, whereas inactivation of IDD14 in idd14-1 results in increased transpiration and reduced drought tolerance. 

结果2-IDD14影响植株对ABA敏感性：Altered IDD14 expression affects ABA sensitivity and ABA-mediated stomatal closure. 

结果3-IDD14与ABFs互作：IDD14 can physically interact with ABF1-4 and subsequently promote their transcriptional activities. 

结果4-ABFs作用于IDD14的下游，共同作用于干旱胁迫响应：Moreover, ectopic expression and mutation of ABFs could suppress and enhance plant sensitivity to drought stress in the idd14-1 mutant, respectively. 

结论：Our results demonstrate that IDD14 forms a functional complex with ABFs and positively regulates drought-stress responses, thus revealing a previously unidentified role of IDD14 in ABA signaling and drought responses.

 摘 要 

IDD转录因子介导植物生长和发育多种生物学进程。先前，作者发现拟南芥IDD亚家族调控空间上的生长素积累，从而影响植物的器官形态发生和重力响应。但是，IDD亚家族在植物胁迫响应中的作用还不清楚。本文中，作者结合生理、生化、分子和遗传学方法，发现IDD14能够与bZIP类结合因子/AREB结合蛋白（ABFs/AREBs）协同作用于ABA介导的干旱耐受性。IDD14的功能获得突变体idd14-1D存在叶片水分丢失减少的表型，并且干旱耐受性增强；相反，IDD14失活突变idd14-1会导致植株蒸腾作用的增强，同时干旱耐受性减弱。改变IDD14基因的表达会影响植株对于ABA的敏感性以及ABA介导的气孔关闭。IDD14能够与 ABF1-4发生物理互作，随后促进后者的转录活性。此外，异位表达和突变体ABFs能够分别抑制和增强idd14-1突变体植物对于干旱胁迫的敏感性。本文的研究结果揭示了IDD14蛋白与ABFs形成一个功能性复合物，正调控植物的干旱胁迫响应，因此揭示了IDD14先前未曾报道的功能，即作用于ABA信号转导和干旱响应。

 崔大勇