Tsuge T, Tsukaya H, Uchimiya H
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Japan.
Development. 1996 May;122(5):1589-600. doi: 10.1242/dev.122.5.1589.
For genetic analysis of mechanisms of leaf morphogenesis, we chose Arabidopsis thaliana (L.) Heynh. as a model for leaf development in dicotyledonous plants. Leaves of the angustifolia mutant were the same length as but narrower and thicker than wild-type leaves. The total number of cells in leaf blades of angustifolia plants was the same as in the wild type. At the cellular level in the angustifolia mutant it was found that the cells were smaller in the leaf-width direction and larger in the leaf-thickness direction than in wild type, revealing the function of the ANGUSTIFOLIA gene, which is to control leaf morphology by regulating polarity-specific cell elongation. The existence of similar genes that regulate leaf development in the length direction was, therefore, predicted. Three loci and several alleles associated with short-leaved mutants were newly isolated as rotundifolia mutants. The rotundifolia3 mutant had the same number of cells as the wild type, with reduced cell elongation in the leaf-length direction. The features of the angustifolia rotundifolia3 double mutant indicated that ANGUSTIFOLIA and ROTUNDIFOLIA3 genes act independently. We propose that leaf expansion in Arabidopsis involves at least two independent developmental processes: width development and length development, with the ANGUSTIFOLIA and ROTUNDIFOLIA3 genes playing different polarity-specific roles in cell elongation.
为了对叶片形态发生机制进行遗传分析，我们选择拟南芥（Arabidopsis thaliana (L.) Heynh.）作为双子叶植物叶片发育的模型。狭叶突变体的叶片长度与野生型叶片相同，但更窄且更厚。狭叶植物叶片中的细胞总数与野生型相同。在狭叶突变体的细胞水平上发现，与野生型相比，其细胞在叶片宽度方向上更小，而在叶片厚度方向上更大，这揭示了狭叶基因的功能，即通过调节极性特异性细胞伸长来控制叶片形态。因此，预测存在在叶片长度方向上调节叶片发育的类似基因。作为圆叶突变体，新分离出了三个与短叶突变体相关的位点和几个等位基因。圆叶3突变体的细胞数量与野生型相同，但在叶片长度方向上细胞伸长减少。狭叶圆叶3双突变体的特征表明狭叶基因和圆叶3基因独立发挥作用。我们提出拟南芥中的叶片扩展至少涉及两个独立的发育过程：宽度发育和长度发育，狭叶基因和圆叶3基因在细胞伸长中发挥不同的极性特异性作用。
