RUI: Molecular Genetic Analysis of Chlorophyll b Synthesis in Arabidopsis

RUI：拟南芥叶绿素 b 合成的分子遗传学分析

• 批准号: 0084274
• 负责人: Judith Brusslan
• 金额: $ 24万
• 依托单位: California State University-Long Beach
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0084274&HistoricalAwards=false
• 关键词: RUI; Molecular; Genetic; Analysis; Chlorophyll

Chlorophyll (Chl) b binds and stabilizes the light harvesting complex proteins of photosystem II in vascular and non-vascular plants, green algae and prochlorophytes. Chl b is synthesized from Chl a in a reaction that requires chlorophyll a oxygenase, the product of the Arabidopsis AtCAO gene. This project will yield transgenic plants that overexpress AtCAO in order to observe if the stable ratio of Chl a to Chl b can be perturbed. Plants with constitutive and inducible promoters will be produced, AtCAO mRNA and protein level will be measured, and rates of Chl b synthesis will be determined. The phenotypes of overproducing lines will be examined to determine if an extra large PSII light harvesting complex is formed. The second objective will be the production of an AtCAO antibody for measurement of protein levels and for suborganelle localization by immunogold labeling. The third objective concerns a mutant, conditional chlorina, that has decreased levels of Chl, especially Chl b, under moderate light intensity. This line appears yellow-green under moderate light intensity, and this visible phenotype correlates to partial loss of Lhcb proteins located in the inner and outer antenna complex. This line has been used to screen for mutants that turn less yellow-green under moderate light intensity, cch suppressors. One of these suppressor lines has been shown to have a phenotype that is visible during segregation of the F2. Characterization and mapping of this, and other suppressors, are proposed. The final objective is to initiate a new project in the laboratory; an analysis of the very high-light responsive promoters of the nuclear Elip1 and Elip2 genes. Both Elip genes are induced 100-fold after four hours at very high light intensity. These studies could lead to an understanding of the factors that are required for the exciton-dissipating chloroplast to communicate with the nucleus. Along with furthering knowledge about the regulation and localization of Chl b synthesis, and chloroplast-nuclear communication, talented undergraduate and Masters degree students, many of them from minorities that are underrepresented in the sciences, will receive training for research careers.

叶绿素（Chl） b在维管和非维管植物、绿藻和原绿藻中结合并稳定光系统II的光收集复合蛋白。Chl b是在一个需要叶绿素a加氧酶的反应中由Chl a合成的，叶绿素a是拟南芥AtCAO基因的产物。本项目将产生过表达AtCAO的转基因植株，以观察Chl a与Chl b的稳定比例是否会受到干扰。将产生具有组成启动子和诱导启动子的植株，测定AtCAO mRNA和蛋白水平，并测定Chl b的合成速率。将检查高产系的表型，以确定是否形成了超大的PSII光收集复合体。第二个目标将是生产一种AtCAO抗体，用于测量蛋白质水平和通过免疫金标记进行亚细胞器定位。第三个目标涉及一种突变体，条件氯化物，它在中等光照强度下降低了Chl水平，特别是Chl b。这条线在中等光照强度下呈现黄绿色，这种可见表型与位于内外天线复合体的Lhcb蛋白的部分丢失有关。这条线被用来筛选在中等光照强度下变黄变绿较少的突变体，即抑制因子。其中一种抑制系已被证明具有在F2分离期间可见的表型。提出了这种抑制因子和其他抑制因子的表征和映射。最终目标是在实验室中启动一个新项目；核Elip1和Elip2基因的高光响应启动子分析。在非常高的光照强度下，两种Elip基因在4小时后被诱导100倍。这些研究可能导致对激子耗散叶绿体与细胞核通信所需的因素的理解。随着对Chl b合成的调控和定位以及叶绿体-核通讯的进一步了解，有才华的本科生和硕士学位学生（其中许多来自科学领域代表性不足的少数民族）将接受研究职业的培训。