Gerbera Laboratory, Department of Agricultural Sciences, PO Box 27 (Latokartanonkaari 7), FIN-00014 University of Helsinki, Finland.
Ann Bot. 2011 Jun;107(9):1491-9. doi: 10.1093/aob/mcr112. Epub 2011 May 13.
The family of MADS box genes is involved in a number of processes besides controlling floral development. In addition to supplying homeotic functions defined by the ABC model, they influence flowering time and transformation of vegetative meristem into inflorescence meristem, and have functions in roots and leaves. Three Gerbera hybrida At-SOC1-like genes (Gh-SOC1-Gh-SOC3) were identified among gerbera expressed sequence tags.
Evolutionary relationships between SOC1-like genes from gerbera and other plants were studied by phylogenetic analysis. The function of the gerbera gene Gh-SOC1 in gerbera floral development was studied using expression analysis, protein-protein interaction assays and reverse genetics. Transgenic gerbera lines over-expressing or downregulated for Gh-SOC1 were obtained using Agrobacterium transformation and investigated for their floral phenotype.
Phylogenetic analysis revealed that the closest paralogues of At-SOC1 are Gh-SOC2 and Gh-SOC3. Gh-SOC1 is a more distantly related paralogue, grouping together with a number of other At-SOC1 paralogues from arabidopsis and other plant species. Gh-SOC1 is inflorescence abundant and no expression was seen in vegetative parts of the plant. Ectopic expression of Gh-SOC1 did not promote flowering, but disturbed the development of floral organs. The epidermal cells of ray flower petals appeared shorter and their shape was altered. The colour of ray flower petals differed from that of the wild-type petals by being darker red on the adaxial side and greenish on the abaxial surface. Several protein-protein interactions with other gerbera MADS domain proteins were identified.
The At-SOC1 paralogue in gerbera shows a floral abundant expression pattern. A late petal expression might indicate a role in the final stages of flower development. Over-expression of Gh-SOC1 led to partial loss of floral identity, but did not affect flowering time. Lines where Gh-SOC1 was downregulated did not show a phenotype. Several gerbera MADS domain proteins interacted with Gh-SOC1.
MADS 盒基因家族除了控制花发育之外，还参与了许多过程。除了提供 ABC 模型定义的同异位功能外，它们还影响开花时间和营养芽分生组织向花序分生组织的转化，并在根和叶中具有功能。从非洲菊表达序列标签中鉴定出 3 个拟南芥 SOC1 样基因（Gh-SOC1-Gh-SOC3）。
通过系统发育分析研究了 SOC1 样基因在拟南芥和其他植物之间的进化关系。利用表达分析、蛋白-蛋白相互作用测定和反向遗传学研究了拟南芥基因 Gh-SOC1 在非洲菊花发育中的功能。利用农杆菌转化获得过表达或下调 Gh-SOC1 的转基因非洲菊品系，并对其花表型进行研究。
系统发育分析表明，At-SOC1 的最接近的旁系同源物是 Gh-SOC2 和 Gh-SOC3。Gh-SOC1 是一个更远的旁系同源物，与拟南芥和其他植物物种的一些其他 At-SOC1 旁系同源物聚在一起。Gh-SOC1 在花序中丰富表达，在植物的营养部分没有表达。Gh-SOC1 的异位表达并没有促进开花，但扰乱了花器官的发育。射线花瓣的表皮细胞看起来更短，形状也发生了改变。射线花瓣的颜色与野生型花瓣不同，正面为暗红色，背面为绿色。鉴定出与其他非洲菊 MADS 结构域蛋白的几种蛋白-蛋白相互作用。
非洲菊中的 At-SOC1 旁系同源物表现出花丰富表达的模式。晚期花瓣表达可能表明其在花发育的最后阶段起作用。过表达 Gh-SOC1 导致花部分丧失身份，但不影响开花时间。下调 Gh-SOC1 的品系没有表现出表型。几个非洲菊 MADS 结构域蛋白与 Gh-SOC1 相互作用。
