Miyoshi Kazumaru, Ahn Byung-Ohg, Kawakatsu Taiji, Ito Yukihiro, Itoh Jun-Ichi, Nagato Yasuo, Kurata Nori
Plant Genetics Laboratory, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan.
Proc Natl Acad Sci U S A. 2004 Jan 20;101(3):875-80. doi: 10.1073/pnas.2636936100. Epub 2004 Jan 7.
During postembryonic development of higher plants, the shoot apical meristem produces lateral organs in a regular spacing (phyllotaxy) and a regular timing (plastochron). Molecular analysis of mutants associated with phyllotaxy and plastochron would greatly increase understanding of the developmental mechanism of plant architecture because phyllotaxy and plastochron are fundamental regulators of plant architecture. pla1 of rice is not only a plastochron mutant showing rapid leaf initiation without affecting phyllotaxy, but also a heterochronic mutant showing ectopic shoot formation in the reproductive phase. Thus, pla1 provides a tool for analyzing the molecular basis of temporal regulation in leaf development. In this work, we isolated the PLA1 gene by map-based cloning. The identified PLA1 gene encodes a cytochrome P450, CYP78A11, which potentially catalyzes substances controlling plant development. PLA1 is expressed in developing leaf primordia, bracts of the panicle, and elongating internodes, but not in the shoot apical meristem. The expression pattern and mutant phenotype suggest that the PLA1 gene acting in developing leaf primordia affects the timing of successive leaf initiation and the termination of vegetative growth.
在高等植物胚后发育过程中，茎尖分生组织以规则的间距（叶序）和规则的时间间隔（叶龄期）产生侧生器官。对与叶序和叶龄期相关的突变体进行分子分析，将极大地增进我们对植物形态发育机制的理解，因为叶序和叶龄期是植物形态的基本调控因子。水稻的pla1不仅是一个叶龄期突变体，表现为叶片快速起始且不影响叶序，还是一个异时突变体，在生殖阶段出现异位茎形成。因此，pla1为分析叶片发育中时间调控的分子基础提供了一个工具。在这项研究中，我们通过图位克隆分离出了PLA1基因。鉴定出的PLA1基因编码一种细胞色素P450，即CYP78A11，它可能催化控制植物发育的物质。PLA1在发育中的叶原基、圆锥花序的苞片和伸长的节间中表达，但在茎尖分生组织中不表达。这种表达模式和突变体表型表明，在发育中的叶原基中起作用的PLA1基因影响连续叶片起始的时间和营养生长的终止。
