EAGER-Forgotten N-conjugate cytokinins and their active role during senescence

EAGER-被遗忘的N-结合细胞分裂素及其在衰老过程中的积极作用

• 批准号: 2033337
• 负责人: Aaron Rashotte
• 金额: $ 24.9万
• 依托单位: Auburn University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2033337&HistoricalAwards=false
• 关键词: EAGER; Forgotten; conjugate; cytokinins; their

Cytokinin is a plant hormone that is essential to normal growth and development in plants. One key function of cytokinin is to keep older leaves green and growing efficiently by delaying their eventual yellowing and aging, called senescence. Study of how cytokinin regulates the delay of senescence will help researchers learn how to increase growth, performance, and yield of agricultural crops. Cytokinin is a blanket term for a class of about 30 chemically related compounds that regulate these growth processes. A sub-group of understudied cytokinin compounds, known as N-conjugate cytokinins, are also involved in delaying leaf senescence, yet their role and function are unknown. These N-conjugate cytokinins have not been examined for nearly 35 years and only recently were identified as being active regulators of this developmental process. This research aims to understand the role of these forgotten cytokinins in leaf aging using classical bioassays and physiological measurement paired with cutting edge analyses. Graduate and undergraduate students will be trained in basic research, and summer research experiences will be offered to high school students to increase exposure to the plant sciences.Nearly all cytokinin research has focused on cytokinin bases forms like trans-Zeatin (tZ) and isopentenyladenine (iP), which are known to bind cytokinin receptors and trigger canonical cytokinin responses, such as delaying senescence. Yet recently findings indicate that the unstudied N-conjugate cytokinins forms can also delay senescence suggesting a re-examination of the role of these N-conjugate during senescence. Bioassays will be used to directly measure changes in the levels of all cytokinin forms and will use GC-MS/MS to determine effects on the cytokinin biosynthesis pathway during development. Transcriptome and proteome analyses during senescence will be conducted in parallel with physiology and measurements of cytokinin levels to characterize gene expression and protein changes that specifically occur in response to N-conjugate cytokinin vs base cytokinin forms. This high risk and high reward endeavor should uncover the role of these otherwise under-studied cytokinins and explain how different cytokinin compounds delay senescence at the molecular level over development.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.

细胞分裂素是植物正常生长发育所必需的一种植物激素。细胞分裂素的一个关键功能是通过延缓老叶子的最终变黄和老化，即衰老，来保持老叶子的绿色和有效生长。细胞分裂素如何调节延缓衰老的研究将有助于研究人员了解如何提高农作物的生长、性能和产量。细胞分裂素是对一类大约30种化学相关的调节这些生长过程的化合物的总称。细胞分裂素化合物的一个亚群，被称为n -共轭细胞分裂素，也参与延缓叶片衰老，但它们的作用和功能尚不清楚。这些n偶联细胞分裂素近35年来一直没有被研究过，直到最近才被确定为这一发育过程的积极调节因子。本研究旨在了解这些被遗忘的细胞分裂素在叶片老化中的作用，采用经典的生物测定和生理测量相结合的尖端分析。研究生和本科生将接受基础研究方面的培训，高中生将获得夏季研究经验，以增加对植物科学的接触。几乎所有的细胞分裂素研究都集中在细胞分裂素的碱基形式上，如反式玉米素（tZ）和异戊烯腺嘌呤（iP），它们被认为可以结合细胞分裂素受体并引发典型的细胞分裂素反应，如延缓衰老。然而，最近的研究结果表明，未经研究的n -缀合细胞分裂素形式也可以延缓衰老，这表明重新检查这些n -缀合物在衰老过程中的作用。生物测定将用于直接测量所有细胞分裂素形式水平的变化，并将使用GC-MS/MS来确定在发育过程中对细胞分裂素生物合成途径的影响。衰老期间的转录组和蛋白质组分析将与生理和细胞分裂素水平的测量同时进行，以表征基因表达和蛋白质变化，这些变化是对n偶联细胞分裂素和碱性细胞分裂素形式的特异性反应。这项高风险、高回报的努力将揭示这些尚未得到充分研究的细胞分裂素的作用，并解释不同的细胞分裂素化合物如何在分子水平上延缓发育过程中的衰老。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。