US - Czech Collaboration on the Role of Cytokinin Conjugation in Leaf Senescence

美国-捷克合作研究细胞分裂素结合在叶片衰老中的作用

• 批准号: 0086731
• 负责人: Machteld Mok
• 金额: $ 2.61万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0086731&HistoricalAwards=false
• 关键词: US; Czech; Collaboration; Role; Cytokinin

This is an international collaborative research project between Oregon State University and the Institute of Experimental Botany of the Czech Republic focusing on the regulation of senescence by a plant hormone (cytokinin). The research will lead to a better understanding of the processes leading to cessation of growth in annual plants at the end of the season. The collaboration is a continuation of a previous COBASE project between Machteld Mok/David Mok and Radomira Vankova and the research is an extension of a NSF-funded project to the Mok lab (9981974). The collaboration combines research expertise of the two labs to address a classical topic in plant physiology with molecular tools.Cytokinins are hormones promoting cell division and regulating many phases of whole plant development. Zeatin is the most common and active natural cytokinin. Of the wide spectrum of zeatin metabolites, those derived from modifications of the N6-isoprenoid side-chain are of particular interest since biological activity is largely dependent on side-chain configuration. O-Glucosides of zeatin and ribosylzeatin occur in most plant species examined and are particularly abundant at the onset of leaf senescence. By virtue of their resistance to cytokinin oxidase attack and ready conversion to zeatin via b-glucosidase hydrolysis, O-glucosides are considered to be storage and transport forms of active cytokinins. However, their precise function has not been defined. Molecular tools, genes encoding the zeatin O-glucosyltransferase (ZOG1) and a b-glucosidase (Bgl4), are now available to examine this question. Gene expression, enzyme activity and distribution of zeatin, ribosylzeatin, and their O-glucosides will be determined in tobacco at specific stages of leaf development. The effects of modifying O-glucosylation and sugar hydrolysis on maturation and senescence will be examined by generating transgenic plants harboring the ZOG1 and Bgl4 genes in sense and anti-sense orientations. As few cytokinin-related genes have been isolated, the proposed study offers a unique approach to examine the control of a specific metabolic step on a single developmental process, and should bring new perspective to the hormonal regulation of leaf senescence.

这是俄勒冈州立大学和捷克共和国实验植物研究所之间的一个国际合作研究项目，重点研究植物激素（细胞分裂素）对衰老的调节。这项研究将有助于更好地了解导致一年生植物在季节结束时停止生长的过程。此次合作是 Machteld Mok/David Mok 和 Radomira Vankova 之间先前 COBASE 项目的延续，该研究是 NSF 资助的 Mok 实验室项目 (9981974) 的延伸。此次合作结合了两个实验室的研究专业知识，利用分子工具解决植物生理学的经典主题。细胞分裂素是促进细胞分裂和调节整个植物发育的许多阶段的激素。玉米素是最常见和最活跃的天然细胞分裂素。在广泛的玉米素代谢物中，源自 N6-类异戊二烯侧链修饰的那些代谢物特别令人感兴趣，因为生物活性在很大程度上取决于侧链构型。玉米素和核糖基玉米素的 O-葡萄糖苷存在于所检查的大多数植物物种中，并且在叶子衰老开始时特别丰富。由于其对细胞分裂素氧化酶攻击的抵抗力以及通过 b-葡萄糖苷酶水解易于转化为玉米素，O-葡萄糖苷被认为是活性细胞分裂素的储存和运输形式。然而，它们的确切功能尚未定义。现在可以使用分子工具、编码玉米素 O-葡萄糖基转移酶 (ZOG1) 和 β-葡萄糖苷酶 (Bgl4) 的基因来研究这个问题。烟草中玉米素、核糖基玉米素及其 O-葡萄糖苷的基因表达、酶活性和分布将在叶片发育的特定阶段进行测定。将通过产生具有有义和反义方向的 ZOG1 和 Bgl4 基因的转基因植物来检查修饰 O-葡萄糖基化和糖水解对成熟和衰老的影响。由于分离出的细胞分裂素相关基因很少，因此拟议的研究提供了一种独特的方法来检查单个发育过​​程中特定代谢步骤的控制，并且应该为叶片衰老的激素调节带来新的视角。