Tobeña-Santamaria Rafael, Bliek Mattijs, Ljung Karin, Sandberg Göran, Mol Joseph N M, Souer Erik, Koes Ronald
Department of Developmental Genetics, Institute for Molecular Biological Sciences, Vrije Universiteit, Biocentrum Amsterdam, 1081 HV Amsterdam, The Netherlands.
Genes Dev. 2002 Mar 15;16(6):753-63. doi: 10.1101/gad.219502.
The mechanisms that determine the relative positions of floral organs, and thereby their numbers, is a poorly understood aspect of flower development. We isolated a petunia mutant, floozy (fzy), in which the formation of floral organ primordia in the outermost three floral whorls and one of the two bracts at the base of the flower is blocked at an early stage. In addition, fzy mutants fail to generate secondary veins in leaves and bracts and display a decreased apical dominance in the inflorescence. FZY encodes an enzyme with homology to flavin mono-oxygenases and appears to be the ortholog of YUCCA genes of Arabidopsis. FZY is expressed in young leafs and bracts and in developing flowers. In young floral meristems FZY is expressed in the center of the meristem dome and, later, expression becomes localized on the flanks of the initiating petal and stamen primordia and at several sites in maturing anthers and carpels. These findings indicate that FZY is involved in synthesizing a signaling compound that is required for floral organ initiation and specification of the vascularization pattern in leaves. Although fzy mutants contain normal auxin levels, ectopic expression of FZY results in excessive auxin accumulation, suggesting that the signaling compound is auxin.
决定花器官相对位置从而决定其数量的机制，是花发育过程中一个尚未被充分理解的方面。我们分离出了一个矮牵牛突变体，floozy（fzy），在该突变体中，最外面三轮花器官原基以及花基部两片苞片之一的原基形成在早期就被阻断。此外，fzy突变体在叶片和苞片中无法形成次生叶脉，并且在花序中表现出顶端优势减弱。FZY编码一种与黄素单加氧酶具有同源性的酶，并且似乎是拟南芥YUCCA基因的直系同源物。FZY在幼叶、苞片以及发育中的花中表达。在幼嫩的花分生组织中，FZY在分生组织顶端的中心表达，随后，表达定位在起始花瓣和雄蕊原基的侧面以及成熟花药和心皮的几个部位。这些发现表明，FZY参与合成一种信号化合物，该化合物是花器官起始和叶片维管化模式特化所必需的。尽管fzy突变体含有正常水平的生长素，但FZY的异位表达会导致生长素过度积累，这表明该信号化合物是生长素。
