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

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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.