Tandre K, Albert V A, Sundås A, Engström P
Department of Physiological Botany, Uppsala University, Sweden.
Plant Mol Biol. 1995 Jan;27(1):69-78. doi: 10.1007/BF00019179.
A set of MADS-box genes in flowering plants encode transcription factors that control both flower meristem formation and organ identity in the developing flower. In this report we present the first documentation of the presence of MADS-box genes in a non-flowering seed plant, and indeed from a plant bearing truly unisexual reproductive axes. A MADS-box-specific screening of a cDNA library from immature female strobili of the conifer Norway spruce, Picea abies (L.) Karst, resulted in cDNA clones that correspond to three different deficiens-agamous-like (dal) genes, dal1, dal2 and dal3. In addition to the MADS box, the spruce genes contain a second sequence element conserved among angiosperm genes, the K box, which is located downstream to the MADS box. A phylogenetic analysis of the nucleotide sequences confirms common ancestry of the gene superfamily. dal1 is related to agl2, agl4 and agl6 from Arabidopsis thaliana, all genes with unknown functions, and is expressed in vegetative as well as reproductive shoots on the adult spruce tree. dal2 is sister to angiosperm genes that control the identity of sexual organs, and is expressed only in the developing male and female strobili. dal3 is related to the vegetatively expressed tomato gene tm3 and is transcribed in both vegetative and reproductive shoots. These results strongly suggest that the functional and structural complexity within the MADS-box superfamily of reproduction-control genes is an ancestral property of seed plants and not a novelty in the angiosperm lineage.
开花植物中的一组MADS-box基因编码转录因子，这些转录因子控制着花分生组织的形成以及发育中花朵的器官特性。在本报告中，我们首次记录了非开花种子植物中存在MADS-box基因，实际上是来自具有真正单性生殖轴的植物。对挪威云杉（Picea abies (L.) Karst）未成熟雌球果的cDNA文库进行MADS-box特异性筛选，得到了与三个不同的deficiens-agamous-like（dal）基因dal1、dal2和dal3相对应的cDNA克隆。除了MADS框外，云杉基因还包含被子植物基因中保守的第二个序列元件K框，它位于MADS框的下游。对核苷酸序列的系统发育分析证实了该基因超家族的共同祖先。dal1与拟南芥中的agl2、agl4和agl6相关，所有这些基因的功能均未知，并且在成年云杉树的营养枝和生殖枝中均有表达。dal2是控制性器官特性的被子植物基因的姐妹基因，仅在发育中的雄球果和雌球果中表达。dal3与营养表达的番茄基因tm3相关，并且在营养枝和生殖枝中均有转录。这些结果强烈表明，MADS-box生殖控制基因超家族内的功能和结构复杂性是种子植物的祖传特性，而非被子植物谱系中的新奇特性。
