Enhanced Growth and Stress Tolerance in Plants After Treatment With Ethylene

由于人口增加、气候变化和可耕地减少，提高作物产量是一项重大挑战。提高植物生长和抗逆性的方法是解决这一挑战的关键。然而，这些方法的成功并不能保证，因为生长的改善往往导致应力耐受性的降低，反之亦然。这种权衡可以对提高植物产量的生物工程策略产生深远的影响。植物受到包括乙烯在内的多种激素的调节，乙烯是一种调节植物生长、发育和应激反应的许多方面的气体。我们最近发现，在幼苗发育早期，短暂的乙烯处理会导致长期的变化，增加生长和抗逆性。这可能为提高植物活力和产量提供一种简单的技术。我们建议使用多种科学方法来确定这种意想不到的结果的机制，并制定适用于各种植物物种的治疗方案。该研究结果将揭示植物处理的新范式，并将为基因改造提供靶点，以提高植物的生长和活力，从而改善粮食安全。总的来说，这项研究预计将对作物生产力产生重大影响，并加强科学和教育基础设施，并为包括妇女和少数民族在内的学生提供机会。我们最近做了一个惊人的观察，在黑暗中萌发的种子进行乙烯处理，然后转移到光照和无乙烯的条件下，植物生长得更大，表现出更强的非生物胁迫耐受性。与这些变化相关的是，乙烯预处理还导致光合作用和淀粉、碳水化合物和各种核心代谢物水平的长期增加。我们假设，在幼苗发育的关键时期，短暂的乙烯处理会导致表观遗传变化，导致光合作用和碳代谢的长期增加，从而增加碳水化合物水平，从而增强生长和胁迫耐受性。这项研究的主要目标将是验证这一假设，揭示其机制，并确定乙烯的这些影响在植物物种中的广泛分布。为了做到这一点，我们提出了一套完整的实验来确定信号通路，并确定光合作用和碳水化合物代谢中发生的变化。这些研究涉及多个时空尺度，并结合遗传学、分子生物学、生物化学和生理学来提供植物活力增强的机理细节。这些研究将提供亚细胞事件和整个植物反应之间的联系。本研究由综合有机体系统部的生理机制和生物力学项目以及分子和细胞生物科学部的细胞动力学和功能集群共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Enhancing crop yields is a major challenge because of an increasing human population, climate change, and reduction in arable land. Methods to increase growth and stress resistance in plants are key to addressing this challenge. However, the success of these approaches is not guaranteed since improvement in growth often leads to a decrease in stress tolerance and vice versa. This trade-off can have profound implications on bioengineering strategies to enhance plant yield. Plants are regulated by a variety of hormones including ethylene, which is a gas known to regulate many aspects of plant growth, development, and stress responses. We recently discovered that transient ethylene treatment early in seedling development leads to long-lasting changes that increase both growth and stress tolerance. This potentially provides a simple technique to improve plant vigor and yield. We propose to use a variety of scientific approaches to determine the mechanisms for this unanticipated result and develop treatment protocols applicable to a variety of plant species. Results from the proposed research will reveal new paradigms for treating plants and will provide targets for genetic modification to increase plant growth and vigor to improve food security. Overall, this research is expected to have significant impact on crop productivity, and enhance scientific and educational infrastructure and opportunities for students mentored including women and minorities. We recently made the surprising observation that ethylene treatment of germinating seeds in darkness, followed by transfer to light and ethylene-free conditions caused plants to grow much larger and display enhanced abiotic stress tolerance. Correlating with these changes, ethylene pre-treatment also led to long-lasting increases in both photosynthesis and the levels of starch, carbohydrates, and various core metabolites. We hypothesize that transient ethylene treatment of seedlings at critical times in their development results in epigenetic changes that cause long-lasting increases in photosynthesis and carbon metabolism leading to increased carbohydrate levels which enhance both growth and stress tolerance. The main goals of this research will be to test this hypothesis, uncover the mechanisms responsible, and establish how wide-spread these effects of ethylene are across plant species. To do this we propose an integrated set of experiments do determine the signaling pathway(s) responsible and determine the changes that occur in photosynthesis and carbohydrate metabolism. These studies involve multiple spatiotemporal scales and combine genetics, molecular biology, biochemistry, and physiology to provide mechanistic details about enhanced plant vigor. These studies will furnish links between subcellular events and whole plant responses. This research is jointly funded by the Physiological Mechanisms and Biomechanics program in the Division of Integrative Organismal Systems and the Cellular Dynamics and Functions cluster in the Division of Molecular and Cellular Biosciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.