Environmental and hormonal control of seed development and germination

植物由于其固着的性质而面临许多生物和非生物胁迫，并且已经进化出各种策略，通过这些策略它们可以有效地平衡生长和对胁迫物的防御。植物所采用的策略是在任何给定时刻保持适当的激素平衡。植物激素是小分子，其信号通路相互作用，共同形成一个复杂的串扰网络，调节植物对环境压力的反应。激素脱落酸（阿坝）对于启动植物内的应激反应、抑制生长和促进在各种应激下的存活至关重要。无论植物受到何种类型的胁迫，其结果都是能量剥夺，激活能量传感器以维持能量稳态。SnRK 1（Sucrose non-fermenting Related Kinase 1）是酵母Snf 1和哺乳动物AMPK能量传感器的植物直系同源物。值得注意的是，AMPK是一种代谢肿瘤抑制因子，目前是癌症和糖尿病治疗和预防的靶点。SnRK 1激活诱导代谢应激下的大转录重编程以保存能量。尽管这些必需的激酶复合物在能量稳态中起着关键作用，但已知的靶点很少。SnRK 1和阿坝信号通路在胁迫响应过程中相互交叉以促进存活，然而，这种相互作用的机制尚不清楚。种子占我们食物摄入量的70%，作为直接消费和动物饲料。拟议的研究计划旨在了解激素如何调节植物对环境线索的反应，重点是种子发育和早期营养生长。将分子遗传学和靶向系统生物学方法相结合，用于：a）研究非生物胁迫下种子发育和萌发过程中激素串扰的机制; B）了解SnRK 1和阿坝信号通路之间的相互作用机制，这两者在胁迫期间都被激活; c）确定非生物胁迫下种子发育和萌发的新型调节剂。从长远来看，我们的目标是了解植物如何整合内源信号和外部信号以适应不断变化的环境。全球气候变化造成的淡水短缺和气温上升是对粮食安全的主要威胁。植物对环境胁迫的反应能力在生殖发育过程中至关重要，此时水和热胁迫，特别是当两者结合时，会严重降低种子灌浆并造成巨大的产量损失。这在加拿大是一个严重的问题，在过去几年里，气温上升和干旱对小麦、油菜和玉米等重要农作物的产量产生了负面影响。从该计划中获得的知识将有助于未来在种子发育过程中选择具有增强胁迫耐受性的植物，从而大大提高重要农作物的产量。

Plants face a multitude of biotic and abiotic stresses due to their sessile nature and have evolved various strategies through which they can effectively balance growth and defense against stressors. A strategy employed by plants is to maintain an appropriate hormone balance at any given moment. Plant hormones are small molecules whose signaling pathways interact, together forming a complex crosstalk network that regulates the plant's response to environmental stressors. The hormone abscisic acid (ABA) is critical for initiating a stress response within the plant, inhibiting growth and promoting survival under various stresses. Regardless of the type of stress that plants are exposed to, the result is energy deprivation that activates energy sensors to maintain energy homeostasis. SnRK1 (Sucrose non-fermenting Related Kinase1) is the plant ortholog of yeast Snf1 and mammalian AMPK energy sensors. Notably, AMPK is a metabolic tumour suppressor, currently a target for cancer and diabetes treatment and prevention. SnRK1 activation induces large transcriptional reprogramming under metabolic stress to conserve energy. Despite the pivotal role of these essential kinase complexes in energy homeostasis, few targets are known. SnRK1 and ABA signaling pathways intersect during stress responses to promote survival, however, the mechanism of this interaction is unclear. Seeds constitute up to 70% of our food intake, as direct consumption and animal feed. The proposed research program aims to understand how hormones regulate plant responses to environmental cues, with a focus on seed development and early vegetative growth. A combination of molecular genetics and targeted systems biology approaches will be used to: a) study the mechanism of hormone crosstalk during seed development and germination under abiotic stresses; b) understand the mechanisms of interaction between the SnRK1 and ABA signaling pathways, both of which are activated during stress; c) identify novel regulators of seed development and germination under abiotic stresses. In the long term, we aim to understand how plants integrate endogenous signals and external cues to adapt to changing environments. Scarcity of fresh water and increasing temperature due to global climate change are major threats to food security. Plants ability to respond to environmental stressors is critical during reproductive development, at which time water and heat stresses, especially when combined, can severely reduce seed filling and cause great yield losses. This is a great concern in Canada, where increasing temperature and drought have negatively impacted the yield of important agricultural crops, such as wheat, canola and corn in the past years. The knowledge gained from this program will aid in the future selection of plants with enhanced stress tolerance during seed development, greatly improving the yield of important agricultural crops.