Characterization of Negative Regulators of Arabidopsis Trichome Development

拟南芥毛状体发育负调控因子的表征

• 批准号: 0091052
• 负责人: Michael Marks
• 金额: $ 39万
• 依托单位: University of Minnesota-Twin Cities
• 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: 2001-01-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0091052&HistoricalAwards=false
• 关键词: Characterization; Negative; Regulators; Arabidopsis; Trichome

0091052MarksThe development of hairs, called trichomes, on the leaf surface of Arabidopsis plants is being used as a model to study the control of cell fate and differentiation. The model has both basic and practical attributes. Understanding the basic mechanisms that control cell fate and differentiation in multicellular organisms is a key goal in biological research. Given that the mechanisms that control the cell cycle are similar in plants and non-plants, it is possible that the information obtained in studying trichome development will lead to a better understanding of how other cell types differentiate. The model is of practical importance because the trichomes on many plants form the first line of defense againsthostile environmental factors. Many crop plants only have a sparse covering of hairs and the information obtained from this research could lead to new strategies to improve crop plants. In wild type Arabidopsis, leaf trichomes are uniformly spaced over the leaf surface; less than 0.5% of the trichomes develop adjacent to one another. Previous analyses have shown that trichome spacing is not controlled by chance but by a developmentally regulated spacing program. Such analyses indicate that the spacing program involves cell to cell communication that prevents neighboring cells from becoming trichomes.It has been found that the GL1 gene, which is required for trichome initiation, actually inhibits trichome initiation when overexpressed. This inhibition of initiation is not due to co-suppression, as it has been found that 35S::GL1 plants overexpress both GL1 mRNA and protein. It is proposed that overexpression of GL1 results in the production of a leaf-wide lateral inhibition program in which neighboring cells inhibit each other from becoming trichomes. To test this hypothesis, a mutational analysis is being used to identify mutations that can suppress the 35S::GL1 phenotype and increase leaf trichome initiation. One such interesting mutant, called cot, has been extensively characterized. In 35S::GL1 cot plants, many of the cells that surround a trichome enter the trichome pathway. In addition to35S::GL1 cot, other 35S::GL1 mutants have been identified that can suppress the 35S::GL1 phenotype. These new mutants will be characterized, and the most interesting genes will be targeted for positional cloning. Although the original 35S::GL1 mutant population was isolated from chemically mutagenized seed, to facilitate cloning of subsequently identified mutant genes, a new population of 35S::GL1 mutants is being induced by T-DNA tagging.In addition to the above studies, another gene hypothesized to be a negative regulator will be characterized. This gene, called CPC-like 1 (CPL1), also appears to limit trichome initiation when expressed at high levels. It is predicted that the CPL1 mechanism of inhibition is distinct from the mechanism resulting from GL1 overexpression. This will be tested. Finally, it will be determined if microarray analysis using gene chips can detect genes that are differentially expressed in plants overexpressing either GL1 or CPL1.

0091052标记拟南芥属植物叶表面的毛状体的发育被用作研究细胞命运和分化控制的模型。该模型具有基础属性和实用属性。了解多细胞生物体中控制细胞命运和分化的基本机制是生物学研究的一个关键目标。考虑到控制细胞周期的机制在植物和非植物中是相似的，在研究毛状体发育中获得的信息可能会更好地理解其他细胞类型是如何分化的。该模型具有实际意义，因为许多植物上的毛状体形成了抵御不利环境因素的第一道防线。许多农作物只有稀疏的毛发覆盖，从这项研究中获得的信息可能会导致改进农作物的新策略。 在野生型拟南芥中，叶毛状体在叶表面均匀分布;少于0.5%的毛状体彼此相邻发育。以前的分析表明，毛状体间距是不受控制的机会，而是由一个发展调节间距程序。 这些分析表明，间隔程序涉及细胞与细胞的通信，防止相邻细胞成为毛状体。已经发现，GL 1基因，这是毛状体的起始所需的，实际上抑制毛状体的起始时，过表达。这种起始抑制不是由于共抑制，因为已经发现35 S：：GL 1植物过度表达GL 1 mRNA和蛋白质。有人提出，过度表达GL 1的结果在生产的叶宽的侧抑制程序，其中相邻的细胞相互抑制成为毛状体。为了验证这一假设，突变分析被用来确定突变，可以抑制35 S：：GL 1表型和增加叶毛状体的起始。其中一个有趣的突变体，cot，已经被广泛描述。在35 S：：GL 1的棉花植株中，许多围绕毛状体的细胞进入毛状体途径。除了35 S：：GL 1 cot，其他35 S：：GL 1突变体也被鉴定出可以抑制35 S：：GL 1表型。这些新的突变体将被表征，并且最感兴趣的基因将被定位克隆。虽然最初的35 S：：GL 1突变体群体是从化学诱变的种子中分离出来的，但为了便于克隆随后鉴定的突变基因，正在通过T-DNA标记诱导新的35 S：：GL 1突变体群体。这种基因，称为CPC样1（CPL 1），也似乎限制毛状体的起始时，在高水平表达。据预测，CPL 1的抑制机制不同于GL 1过表达引起的机制。这将受到考验。 最后，它将确定是否微阵列分析使用基因芯片可以检测到差异表达的基因在植物中过度表达GL 1或CPL 1。