Kater M M, Colombo L, Franken J, Busscher M, Masiero S, Van Lookeren Campagne M M, Angenent G C
Department of Developmental Biology, DLO-Centre for Plant Breeding and Reproduction Research (CPRO-DLO), Droevendaalsesteeg 1, P.O. Box 16, 6700 AA Wageningen, The Netherlands.
Plant Cell. 1998 Feb;10(2):171-82. doi: 10.1105/tpc.10.2.171.
The C function in Arabidopsis, which specifies stamen and carpel identity, is represented by a single gene called AGAMOUS (AG). From both petunia and cucumber, two MADS box genes have been isolated. Both share a high degree of amino acid sequence identity with the Arabidopsis AG protein. Their roles in specifying stamen and carpel identity have been studied by ectopic expression in petunia, resulting in plants with different floral phenotypes. Cucumber MADS box gene 1 (CUM1) induced severe homeotic transformations of sepals into carpelloid structures and petals into stamens, which is similar to ectopic AG expression in Arabidopsis plants. Overexpression of the other cucumber AG homolog, CUM10, resulted in plants with partial transformations of the petals into antheroid structures, indicating that CUM10 is also able to promote floral organ identity. From the two petunia AG homologs pMADS3 and Floral Binding Protein gene 6 (FBP6), only pMADS3 was able to induce homeotic transformations of sepals and petals. Ectopic expression of both pMADS3 and FBP6, as occurrs in the petunia homeotic mutant blind, phenocopies the pMADS3 single overexpresser plants, indicating that there is no additive effect of concerted expression. This study demonstrates that in petunia and cucumber, multiple AG homologs exist, although they differ in their ability to induce reproductive organ fate.
拟南芥中决定雄蕊和心皮特征的C功能由一个名为AGAMOUS（AG）的单一基因代表。从矮牵牛和黄瓜中分离出了两个MADS盒基因。它们与拟南芥AG蛋白都具有高度的氨基酸序列同一性。通过在矮牵牛中异位表达研究了它们在决定雄蕊和心皮特征方面的作用，结果产生了具有不同花表型的植株。黄瓜MADS盒基因1（CUM1）诱导萼片严重同源异型转化为心皮状结构，花瓣转化为雄蕊，这与拟南芥植株中AG异位表达相似。另一个黄瓜AG同源基因CUM10的过表达导致植株花瓣部分转化为花药状结构，表明CUM10也能够促进花器官特征的形成。从矮牵牛的两个AG同源基因pMADS3和花结合蛋白基因6（FBP6）中，只有pMADS3能够诱导萼片和花瓣的同源异型转化。pMADS3和FBP6的异位表达，如同在矮牵牛同源异型突变体blind中发生的那样，模拟了pMADS3单过表达植株，表明协同表达没有累加效应。这项研究表明，在矮牵牛和黄瓜中存在多个AG同源基因，尽管它们在诱导生殖器官命运的能力上有所不同。
