Mutational Analysis of Stomatal Development in Arabidopsis

气孔由气孔周围的两个保护细胞组成，气孔通过气生植物表皮调节气体交换。对调控气孔模式、决定和分化的基因知之甚少。两个隐性拟南芥突变体被分离出来，too many mouth （tmm）和four lips (flp)，每个都有额外的相邻气孔。两者对气孔产生和决定的影响都大于对气孔形成和分化的影响。TTM似乎既影响前体细胞的形成和活性，也可能是气孔产生的重要调节因子。拟议的研究总体上有三个目标。首先，为了更好地了解表型，Sack博士将尝试：a)分离新的等位基因，b)表征整个植物中气孔表型的分布，c)确定tmm和flp是否诱导气孔基因的异位表达，d)分析突变体中气孔发育的程度，e)确定气孔下的位置和大小是否受到影响，f)表征参与野生型气孔和气孔簇发育的细胞系。第二个目标是分离影响气孔发育的新突变体和位点。第三个主要目标是进行精细映射，以选择合适的克隆策略。这些突变体可能有助于回答植物细胞发育的基本问题，如细胞是如何选择特定命运的，以及分化是如何开始和执行的。从长远来看，考虑到气孔对植物生产力的重要性，了解气孔发育的遗传学和分子生物学将是非常有价值的。＊＊＊

9505687 Sack Stomata consist of two guard cells surrounding a pore that regulates gas exchange through the aerial plant epidermis. Little is known about the genes that regulate stomatal patterning, determination and differentiation. Two recessive Arabidopsis mutants have been isolated, too many mouths (tmm) and four lips (flp), each with extra adjacent stomata. Both affect stomatal production and determination more than patterning or differentiation. ttm appears to affect both precursor cell formation and activity and may be an important regulator of stomatal production. The research proposed has three objectives overall. First, to understand the phenotypes better, Dr. Sack will attempt to: a) isolate new alleles, b) characterize the distribution of the stomatal phenotypes throughout the plant, c) determine whether tmm and flp induce ectopic expression of stomatal genes, d) analyze the extent of pore development in mutants, e) determine whether substomatal placement and size is affected, and f) characterize cell lineages involved in the development of wild type stomata and of stomatal clusters. A second objective is to isolate new mutants and loci affecting stomatal development. The third major objective is to do fine mapping to choose appropriate cloning strategies. These mutants are likely to help answer basic questions of plant cell development such as how cells are selected for specific fates, as well as how differentiation is initiated and executed. In the long term, knowledge of the genetics and molecular biology of stomatal development would be quite valuable given the importance of stomata for plant productivity. ***