Crosstalk between gibberellin and other signaling molecules in the regulation of seed dormancy

赤霉素（GA）是植物产生的信号化合物之一，其在非常低的浓度下影响广泛的发育过程，通常被描述为“植物激素”。GA控制种子发芽或保持休眠的能力，并且这由种子中存在的GA的量和种子对GA的响应介导。种子中过量的GA，或种子对GA的高反应，引发过早萌发。相反，具有低量GA或对GA低响应的种子不能发芽并保持休眠;并且休眠丧失通常与种子GA水平和响应增加相关。GA对种子休眠的调控还通过与茉莉酸（JA）和活性氧（ROS）等参与种子萌发的信号分子的相互作用来实现。种子采用不同的策略来调节GA水平和其他信号分子的反应，反之亦然，从而维持或失去其休眠状态。其中一些策略和相关的调控元件已在双子叶植物的种子中被确定，而对这一现象的理解在单子叶植物中一直滞后，特别是在小麦等谷物中。我的研究计划的总体目标是了解植物激素如何充分详细地调节发育过程，以实现提高作物产量和质量的遗传操作。在此背景下，拟议的研究的具体目标是确定小麦种子使用的新策略来介导GA水平的控制和JA或ROS的反应，反之亦然，从而控制它们在休眠和萌发之间的发育转换。这项研究的结果不仅推进了我们的知识，如何休眠是由GA和ROS或JA之间的串扰调节，但也提供了新的途径，以进一步提高我们的理解的策略激素控制种子休眠和发芽。这项工作的结果也将提供强有力的工具，以提高种子发芽和幼苗建立在不同的环境条件下的成功和成熟种子的耐受性收获前发芽，这是小麦生产中的一个严重问题，从而提高产量和质量。此外，本研究将培养4名博士，1名理学硕士和5名本科生在植物生物学领域具有广泛的技能，使学员能够成功实现职业目标，同时为加拿大对高素质植物生物学家的需求做出贡献。

Gibberellin (GA) is among the plant-produced signaling compounds that influence a wide range of developmental processes at very low concentrations, usually described as “plant hormones”. GA controls the ability of seeds to germinate, or to remain dormant, and this is mediated by the amount of GA present in the seed and seed response to GA. Excess amounts of GA in seeds, or high seed response to the GA, triggers premature germination. Conversely, seeds with low amounts of GA or low response to GA, fail to germinate and remain dormant; and dormancy loss is often associated with increased seed GA level and response. Dormancy control by GA is also mediated by its crosstalk with other signaling molecules that take part in the regulation of seeds’ ability to germinate or not, such as jasmonate (JA) and reactive oxygen species (ROS). Seeds employ different strategies to mediate the regulation of GA level and response by other signaling molecules or vice versa, and thereby maintain or lose their state of dormancy. Several of these strategies and the associated regulatory elements have been identified in the seeds of dicots, and understanding this phenomenon has been lagging in monocots, particularly in cereals such as wheat. The overall goal of my research program is to understand how plant hormones regulate developmental processes in sufficient detail to enable genetic manipulation for enhancing crop yield and quality. Within this context, the specific objective of the proposed research is to identify new strategies used by wheat seeds to mediate the control of GA level and response by JA or ROS and vice versa, and thereby control their developmental switch between dormancy and germination. The outcomes of this study not only advance our knowledge of how dormancy is regulated by crosstalk between GA and ROS or JA but also provide new avenues to further increase our understanding of the strategies underlying hormonal control of seed dormancy and germination. The findings of this work will also provide powerful tools for improving the success of seed germination and seedling establishment under diverse environmental conditions and the tolerance of maturing seeds to preharvest sprouting, a serious problem in the production of wheat, thus enhancing yield and quality. Furthermore, this research will train 4 Ph.D., 1 M.Sc. and 5 undergraduate students with a wide range of skills highly valued in the area of plant biology, making the trainees well-positioned to succeed in their career goals while contributing to Canada’s need for highly qualified plant biologists.