Biochemical and Genetic Regulation of Haustorial Development in Striga

独脚金吸器发育的生化和遗传调控

• 批准号: 9219949
• 负责人: Michael Timko
• 金额: $ 33.4万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1998-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9219949&HistoricalAwards=false
• 关键词: Biochemical; Genetic; Regulation; Haustorial; Development

Parasitic angiosperms attach to and penetrate their host vascular system by the development of a highly specialized organ termed a haustorium. The haustorium serves as a physical bridge that allows the parasite to obtain the water and nutrients necessary for its survival. The development of this unique structure is controlled by a series of chemical signals from the host plant that condition the germination, attachment and penetration stages of growth. Using a combination of in vivo and in vitro approaches Drs. Timko and Riopel have begun to examine the biochemical and genetic mechanisms involved in haustorial induction and development in Striga asiatica (witchweed), a major parasite of agronomically important grasses. They have standardized methods to synchronize growth of a large number of individual plant in order to look at sequential developmental stages (germination, radical extension, pre- attachment haustorial development, attachment, and host penetration) in axenic culture in 3-4 days. The overall goal of the present experiments is to define the cellular and molecular genetic events that constitute the developmental pathway in Striga leading from haustorial initiation to successful attachment and penetration of a susceptible host plant species. They propose to complete the characterization of the putative root and haustorial specific cDNA clones identified in the previous studies and initiate additional rounds of differential screening to identify gene products expressed during the attachment and penetration phases of haustorial development. The goal of these studies is to establish subsets of clones representing gene products temporally and spatially distinct in their expression during the pre-attachment, attachment, and penetration stages of Striga haustorial differentiation. The patterns of gene expression activated during attachment and differentiation of the penetration peg will be compared in Striga haustoria developed in contact with host versus non-host tissues. Such information will assist in the subsequent attempts to define the signal transduction pathway controlling overall haustorial development. A greater understanding of the biochemical and cellular factors governing haustorial differentiation may contribute to future manipulation of host resistance. When completed these studies will provide substantial new information on a unique developmental process in plants.

寄生被子植物通过一种称为吸器的高度特化器官的发育，附着并穿透寄主的维管系统。吸器作为一个物理桥梁，允许寄生虫获得生存所需的水和营养。这种独特结构的发育是由寄主植物的一系列化学信号控制的，这些信号控制着萌发、附着和渗透生长阶段。采用体内和体外相结合的方法。Timko和Riopel已经开始研究亚洲独脚金（striiga asiatica）吸器诱导和发育的生化和遗传机制，独脚金是农学上重要的禾草的主要寄生虫。他们有标准化的方法来同步大量单株植物的生长，以便在3-4天的无菌培养中观察顺序的发育阶段（发芽、根茎延伸、附着前吸器发育、附着和寄主渗透）。本实验的总体目标是确定构成striiga从吸器起始到成功附着和渗透到敏感寄主植物物种的发育途径的细胞和分子遗传事件。他们建议完成先前研究中确定的假定的根和吸器特异性cDNA克隆的表征，并启动额外的差异筛选，以确定在吸器发育的附着和渗透阶段表达的基因产物。这些研究的目的是建立在吸器分化的附着前、附着和渗透阶段具有时间和空间差异的基因产物的克隆亚群。在与宿主和非宿主组织接触发育的吸虫中，将比较渗透聚钉在附着和分化过程中激活的基因表达模式。这些信息将有助于后续尝试定义控制整个吸器发育的信号转导途径。更好地了解控制吸器分化的生化和细胞因素可能有助于未来对宿主抗性的操纵。当这些研究完成后，将为植物独特的发育过程提供大量的新信息。