Maes T, Van de Steene N, Zethof J, Karimi M, D'Hauw M, Mares G, Van Montagu M, Gerats T
Laboratorium of Genetics, University of Ghent, Flemish Institute for Biotechnology, 9000 Ghent, Belgium.
Plant Cell. 2001 Feb;13(2):229-44. doi: 10.1105/tpc.13.2.229.
We have isolated three Apetala2 (Ap2)-like genes from petunia and studied their expression patterns by in situ hybridization. PhAp2A has a high sequence similarity to the A function gene Ap2 from Arabidopsis and a similar expression pattern during flower development, suggesting that they are cognate orthologs. PhAp2B and PhAp2C encode for AP2-like proteins that belong to a different subgroup of the AP2 family of transcription factors and exhibit divergent, nearly complementary expression patterns during flower development compared with PhAp2A. In contrast, all three PhAp2 genes are strongly expressed in endosperm. The phenotype of the petunia A-type mutant blind cannot be attributed to mutations in the petunia Ap2 homologs identified in this study, and reverse genetics strategies applied to identify phap2a mutants indicate that PhAp2A might not be essential for normal perianth development in petunia. Nevertheless, we show that PhAp2A is capable of restoring the homeotic transformations observed in flowers and seed of the ap2-1 mutant of Arabidopsis. Although the interspecific complementation proves that PhAp2A encodes a genuine Ap2 ortholog from petunia, additional factors may be involved in the control of perianth identity in this species.
我们从矮牵牛中分离出三个类Apetala2（Ap2）基因，并通过原位杂交研究了它们的表达模式。PhAp2A与拟南芥的A功能基因Ap2具有高度的序列相似性，且在花发育过程中具有相似的表达模式，这表明它们是同源直系同源基因。PhAp2B和PhAp2C编码的AP2类蛋白属于转录因子AP2家族的不同亚组，与PhAp2A相比，在花发育过程中表现出不同的、几乎互补的表达模式。相比之下，所有三个PhAp2基因在胚乳中均强烈表达。矮牵牛A型突变体blind的表型不能归因于本研究中鉴定出的矮牵牛Ap2同源基因的突变，用于鉴定phap2a突变体的反向遗传学策略表明，PhAp2A可能对矮牵牛正常花被发育并非必不可少。然而，我们表明PhAp2A能够恢复拟南芥ap2-1突变体花和种子中观察到的同源异型转变。尽管种间互补证明PhAp2A编码矮牵牛真正的Ap2直系同源基因，但该物种花被身份的控制可能还涉及其他因素。
