Ectopic expression of an orchid (Oncidium Gower Ramsey) AGL6-like gene promotes flowering by activating flowering time genes in Arabidopsis thaliana
Ectopic expression of an orchid (Oncidium Gower Ramsey) AGL6-like gene promotes flowering by activating flowering time genes in Arabidopsis thaliana
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DOI：
10.1093/pcp/pcg099
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发表时间：
2003-08-01
影响因子：
4.9
通讯作者：
Yang, CH
中科院分区：
文献类型：
--
作者：
Hsu, HF;Huang, CH;Yang, CH
MADS盒基因的AP 1/AGL 9组（OMADS 1）与拟南芥A GAMOUS-like 6基因（AGL 6）具有广泛的同源性，是从兰花（Oncidium Gower Ramsey）中鉴定的。OMADS 1 mRNA在花的顶端分生组织、唇瓣和心皮中均有表达。酵母双杂交分析表明，OMADS 1能够与OMADS 3，一个TM 6样蛋白，参与花的形成和花的起始在兰花强烈的相互作用。转基因拟南芥和烟草异位表达OMADS 1表现出相似的新表型，显着减少植物的大小，开花极早，并失去花序不确定性。此外，在35 S：：OMADS 1拟南芥花中也观察到萼片向心皮样结构和花瓣向雄蕊样结构的同源异型转化。这一结果表明，OMADS 1参与了转基因植物花的形成和起始。进一步分析表明，在35 S：：OMADS 1转基因拟南芥中，开花时间基因FT、CO 1过量表达的供应者（SOC 1）和花分生组织特性基因LEAFY（LFY）、APETALA 1（AP 1）的表达量显著上调。此外，OMADS 1的异位表达挽救了gi-1，co-3中的晚花表型，但不是ft-1和fwa-1突变体。这些结果支持OMADS 1的异位表达通过激活FT和SOC 1影响拟南芥花的转变和形成。
AP1/AGL9 group of MADS box gene, OMADS1, with extensive homology to the Arabidopsis A GAMOUS-like 6 gene (AGL6) was characterized from orchid (Oncidium Gower Ramsey). OMADS1 mRNA was detected in apical meristem and in the lip and carpel of flower. Yeast two-hybrid analysis indicated that OMADS1 is able to strongly interact with OMADS3, a TM6-like protein that was involved in flower formation and floral initiation in orchid. Transgenic Arabidopsis and tobacco ectopically expressed OMADS1 showed similar novel phenotypes by significantly reducing plant size, flowering extremely early, and losing inflorescence indeterminacy. In addition, homeotic conversion of sepals into carpel-like structures and petals into staminoid structures were also observed in flowers of 35S::OMADS1 Arabidopsis. This result indicated that OMADS1 was involved in floral formation and initiation in transgenic plants. Further analysis indicated that the expression of flowering time genes FT, SUPPRESSOR OF OVER EXPRESSION OF CO 1 (SOC1) and flower meristem identity genes LEAFY (LFY), APETALA1 (AP1) was significantly up-regulated in 35S::OMADS1 transgenic Arabidopsis plants. Furthermore, ectopic expression of OMADS1 rescued late-flowering phenotype in gi-1, co-3 but not for ft-1 and fwa-1 mutants. These results supported that ectopic expression of OMADS1 influenced flower transition and formation by acting as an activator for FT and SOC1 in Arabidopsis.