Kamiya Noriko, Nishimura Asuka, Sentoku Naoki, Takabe Eriko, Nagato Yasuo, Kitano Hidemi, Matsuoka Makoto
BioScience Center, Nagoya University, Chikusa, Nagoya, 464-8601 Japan.
Plant Cell Physiol. 2003 Sep;44(9):875-83. doi: 10.1093/pcp/pcg112.
In higher plants, the main elements of the fundamental body plan, the apical-basal and radial patterns, are established during embryogenesis. We have isolated several globular embryo (gle) mutants of rice that fail to develop any embryonic organs. We expected that these gle mutants might include mutants defective in their radial pattern formation ability. We developed two markers specifically staining the L2 and L3 layers (OsSCR and OsPNH1, respectively) and characterized the gle mutants by using these markers in addition to the already developed markers Roc1 (marker for the L1 layer), Ramy1A (marker of the L1 layer of the epithelium), and OSH1 (marker of the apical region). One of the gle mutants, gle4, expressed Roc1 and Ramy1A at the normal positions, but other markers exhibited an abnormal expression pattern; that is, both OsPNH1 and OsSCR were expressed in the central region of the embryo and OSH1 expression was not observed. Calli from the gle4 epithelium regenerated plants with abnormal morphologies. These results indicate that the GLE4 gene is involved in radial pattern formation during rice embryogenesis to differentiate the L2 and L3 layers, but is not involved in the establishment of the L1 layer or in the formation of embryonic organs.
在高等植物中，基本体轴模式的主要要素，即顶基模式和径向模式，是在胚胎发生过程中建立的。我们分离出了几个水稻球形胚（gle）突变体，这些突变体无法发育出任何胚胎器官。我们预期这些gle突变体可能包括在径向模式形成能力方面存在缺陷的突变体。我们开发了两种分别特异性标记L2层和L3层的标记物（分别为OsSCR和OsPNH1），并除了已开发的标记物Roc1（L1层的标记物）、Ramy1A（上皮L1层的标记物）和OSH1（顶端区域的标记物）之外，使用这些标记物对gle突变体进行了表征。其中一个gle突变体gle4在正常位置表达Roc1和Ramy1A，但其他标记物呈现出异常的表达模式；也就是说，OsPNH1和OsSCR都在胚胎的中央区域表达，而未观察到OSH1的表达。来自gle4上皮的愈伤组织再生出形态异常的植株。这些结果表明，GLE4基因在水稻胚胎发生过程中参与径向模式的形成以区分L2层和L3层，但不参与L1层的建立或胚胎器官的形成。
