Function of AP2/ERF transcription factors in phytochrome signalling

AP2/ERF转录因子在光敏色素信号传导中的功能

• 批准号: 499988350
• 负责人: Professor Dr. Andreas Hiltbrunner
• 金额: --
• 依托单位: Institut für Biologie II
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/499988350?language=en
• 关键词: Function; AP2; ERF; transcription; factors

In order to adapt growth and development to the environment, plants constantly monitor the light conditions in their surrounding using dedicated photoreceptors. Phytochromes are photoreceptors sensitive to the red and far-red range of the light spectrum. Upon sensing light, phytochromes accumulate in the nucleus and regulate the expression of hundreds of genes that control seed germination, seedling establishment, induction of flowering, and many other aspects of growth and development. Seed germination and seed dormancy are important ecological and agronomic traits controlled by light and the phythormones abscisic acid (ABA) and gibberellin (GA). ERF55 and ERF58, two closely related AP2/ERF transcription factors that we identified as novel phytochrome interacting proteins, are expressed in seeds and we found that light-dependent seed germination is enhanced in the erf55 erf58 mutant. Light-activated phytochromes bind ERF55/ERF58 and displace them from promoters of germination-repressing genes such as PIF1, SOM, ABI5, and genes coding for ABA anabolic or GA catabolic enzymes, thereby promoting germination. Based on preliminary data, we hypothesise that ERF55 and ERF58 also play a role in setting the depth of dormancy in response to the light environment perceived by the developing seeds. In the first work package of the proposed project, we aim to test this hypothesis and use DAP-seq to identify target genes of ERF55 and ERF58 with a function in regulation of dormancy. ERF55 and ERF58 belong to subgroup A6 of the AP2/ERF transcription factor family. All members of this subgroup interact with phytochromes but – except for ERF55 and ERF58 – are expressed in seedlings or adult plants and not in seeds. Therefore, in the second work package, we aim to identify the functions of these AP2/ERFs in light signalling in seedlings and adult plants, using CRISPR/Cas9 generated erf higher order mutants and high-throughput screening for potential target genes by DAP-seq. Phytochromes bind to the highly conserved DNA-binding domain of AP2/ERFs, suggesting that binding to – and possibly regulation by – phytochromes may be widespread among AP2/ERFs. Several randomly picked AP2/ERFs from different subgroups indeed interacted with phytochromes. In the third work package, we therefore want to screen the entire AP2/ERF family for members interacting with phytochromes. In summary, we have identified members of the AP2/ERF transcription family as novel interactors of phytochromes. In the proposed project, we want to investigate their function in phytochrome-mediated light responses and elucidate the underlying molecular mechanisms.

为了使生长和发育适应环境，植物使用专用的光感受器不断监测周围的光条件。光敏色素是对光谱的红色和远红色范围敏感的光感受器。在感受到光时，光敏色素在细胞核中积累并调节数百个基因的表达，这些基因控制种子萌发、幼苗建立、开花诱导以及生长和发育的许多其他方面。种子萌发和休眠是植物重要的生态和农艺性状，受光照、脱落酸（阿坝）和赤霉素（GA）等激素的调控。ERF 55和ERF 58，两个密切相关的AP 2/ERF转录因子，我们确定为新的光敏色素相互作用蛋白，在种子中表达，我们发现，光依赖的种子萌发增强的erf 55 erf 58突变体。光激活的光敏色素结合ERF 55/ERF 58，并将它们从发芽抑制基因如PIF 1、SOM、ABI 5和编码阿坝合成代谢酶或GA分解代谢酶的基因的启动子上置换，从而促进发芽。基于初步的数据，我们假设ERF 55和ERF 58也发挥作用，在设置休眠的深度，响应于光环境所感知的发展中的种子。在拟议项目的第一个工作包中，我们的目标是测试这一假设，并使用DAP-seq来识别具有调节休眠功能的ERF 55和ERF 58的靶基因。ERF 55和ERF 58属于AP 2/ERF转录因子家族的A6亚群。该亚组的所有成员都与光敏色素相互作用，但除了ERF 55和ERF 58外，它们都在幼苗或成年植物中表达，而不在种子中表达。因此，在第二个工作包中，我们的目标是利用CRISPR/Cas9产生的erf高阶突变体和通过DAP-seq高通量筛选潜在的靶基因，鉴定这些AP 2/ERF在幼苗和成年植物中的光信号传导中的功能。光敏色素与AP 2/ERF的高度保守的DNA结合结构域结合，这表明光敏色素的结合和可能的调节可能在AP 2/ERF中广泛存在。几个随机挑选的AP 2/ERF从不同的亚群确实与光敏色素相互作用。因此，在第三个工作包中，我们希望筛选整个AP 2/ERF家族中与光敏色素相互作用的成员。总之，我们已经确定了AP 2/ERF转录家族的成员作为光敏色素的新的相互作用。在这个项目中，我们希望研究它们在光敏色素介导的光响应中的功能，并阐明潜在的分子机制。