Tzeng Tsai-Yu, Hsiao Chih-Chi, Chi Pei-Ju, Yang Chang-Hsien
Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan 40227, Republic of China.
Plant Physiol. 2003 Nov;133(3):1091-101. doi: 10.1104/pp.103.026997. Epub 2003 Oct 2.
Two AGL2-like MADS-box genes, Lily MADS Box Gene (LMADS) 3 and LMADS4, with extensive homology of LMADS3 to the Arabidopsis SEPALLATA3 were characterized from the lily (Lilium longiflorum). Both LMADS3 and LMADS4 mRNA were detected in the inflorescence meristem, in floral buds of different developmental stages, and in all four whorls of the flower organ. LMADS4 mRNA is also expressed in vegetative leaf and in the inflorescence stem where LMADS3 expression is absent. Transgenic Arabidopsis, which ectopically expresses LMADS3, showed novel phenotypes by significantly reducing plant size, flowering extremely early, and loss of floral determinacy. By contrast, 35S::LMADS4 transgenic plants were morphologically indistinguishable from wild-type plants. The early-flowering phenotype in 35S::LMADS3 transgenic Arabidopsis plants was correlated with the up-regulation of flowering time genes FT, SUPPRESSOR OF OVEREXPRESSION OF CO 1, LUMINIDEPENDENS, and flower meristem identity genes LEAFY and APETALA1. This result was further supported by the ability of 35S::LMADS3 to rescue the late-flowering phenotype in gigantea-1 (gi-1), constans-3 (co-3), and luminidependens-1 but not for ft-1 or fwa-1 mutants. The activation of these flowering time genes is, however, indirect because their expression was unaffected in plants transformed with LMADS3 fused with rat glucocorticoid receptor in the presence of both dexamethasone and cycloheximide.
从麝香百合（Lilium longiflorum）中鉴定出两个类似AGL2的MADS-box基因，百合MADS盒基因（LMADS）3和LMADS4，其中LMADS3与拟南芥SEPALLATA3具有广泛的同源性。在花序分生组织、不同发育阶段的花芽以及花器官的所有四轮中均检测到LMADS3和LMADS4的mRNA。LMADS4 mRNA也在营养叶和花序茎中表达，而LMADS3在这些部位不表达。异位表达LMADS3的转基因拟南芥表现出新奇的表型，植株显著变小、开花极早且失去花的确定性。相比之下，35S::LMADS4转基因植物在形态上与野生型植物没有区别。35S::LMADS3转基因拟南芥植物的早花表型与开花时间基因FT、CONSTANS过表达抑制因子1、LUMINIDEPENDENS以及花分生组织特征基因LEAFY和APETALA1的上调相关。35S::LMADS3能够挽救巨花素-1（gi-1）、CONSTANS-3（co-3）和LUMINIDEPENDENS-1突变体的晚花表型，但不能挽救ft-1或fwa-1突变体，这一结果进一步支持了上述结论。然而，这些开花时间基因的激活是间接的，因为在同时存在地塞米松和环己酰亚胺的情况下，用与大鼠糖皮质激素受体融合的LMADS3转化的植物中它们的表达不受影响。
