Tandre K, Svenson M, Svensson M E, Engström P
Department of Physiological Botany, Uppsala University, Sweden.
Plant J. 1998 Sep;15(5):615-23. doi: 10.1046/j.1365-313x.1998.00236.x.
The Norway spruce (Picea abies) gene DAL2 shows distinct structural similarities to angiosperm MADS-box genes which act in the control of the development of the sexual organs of the flower. Transcription of DAL2 is restricted to the reproductive organs, the unisexual cones, of Norway spruce. In this paper we show that DAL2 in the compound female cone is exclusively expressed in the developing ovule-bearing organ, the ovuliferous scale. When expressed constitutively in transgenic Arabidopsis the gene causes developmental alterations very similar to those observed in plants ectopically expressing the Arabidopsis gene AGAMOUS and the closely related Brassica napus gene BAG1. These alterations include homeotic transformations of floral organs. On the basis of these data and analysis of the phylogeny of the plant MADS-box gene family, we propose that DAL2 acts to control reproductive organ development in spruce. We also propose that DAL2 shares a common origin with AGAMOUS and related genes from other angiosperms, in an ancestral MADS-box gene that was active in the control of ontogeny of ovule-bearing organs in the unknown last common ancestor of conifers and angiosperms.
挪威云杉（Picea abies）基因DAL2与被子植物MADS-box基因呈现出明显的结构相似性，这些被子植物MADS-box基因参与花的性器官发育控制。DAL2的转录仅限于挪威云杉的生殖器官——单性球果。在本文中，我们表明在复合雌球果中，DAL2仅在发育中的含胚珠器官——珠鳞中表达。当在转基因拟南芥中组成型表达时，该基因会导致发育改变，这些改变与在异位表达拟南芥基因AGAMOUS和密切相关的甘蓝型油菜基因BAG1的植物中观察到的改变非常相似。这些改变包括花器官的同源异型转变。基于这些数据以及对植物MADS-box基因家族系统发育的分析，我们提出DAL2在云杉中起着控制生殖器官发育的作用。我们还提出，DAL2与来自其他被子植物的AGAMOUS及相关基因有着共同的起源，它们源自一个祖先MADS-box基因，该基因在针叶树和被子植物未知的最后共同祖先中，活跃于含胚珠器官个体发育的控制过程。
