Regulatory networks that function to specify flower meristems require the function of homeobox genes PENNYWISE and POUND-FOOLISH in Arabidopsis
Regulatory networks that function to specify flower meristems require the function of homeobox genes PENNYWISE and POUND-FOOLISH in Arabidopsis
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DOI：
10.1111/j.1365-313x.2008.03458.x
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发表时间：
2008-06-01
期刊：
影响因子：
7.2
通讯作者：
Smith, Harley M. S.
中科院分区：
文献类型：
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作者：
Kanrar, Siddhartha;Bhattacharya, Monideepa;Smith, Harley M. S.
开花是茎尖分生组织（SAM）从生叶营养分生组织向生花花序分生组织转变的主要发育阶段。在拟南芥中，花分生组织是由开花位点T (FT)-FD复合体和花分生组织识别基因LEAFY （LFY）共同作用于花序分生组织的外围。PENNYWISE （PNY）和POUND-FOOLISH （PNF）两个冗余同源盒基因在营养和花序SAM中表达，调控生殖发育过程中的模式事件，包括花的规格。为了确定PNY和PNF在花规格网络中的作用，我们对这两个同源盒基因与LFY和FT的遗传关系进行了表征。本研究结果表明，LFY在PNY和PNF的下游起作用。LFY的异位表达促进了pny pnf植物的花形成，而异位FT的花规范活性严重减弱。遗传分析表明，当pny和pnf基因突变与lfy基因组合时，显示出一种协同表型，显着降低了花规格并改变了花序模式事件。总之，本研究结果支持PNY和PNF在生殖发育过程中促进LFY表达的模型。同时，FT的成花活性依赖于PNY和PNF的功能。
Flowering is a major developmental phase change that transforms the fate of the shoot apical meristem (SAM) from a leaf-bearing vegetative meristem to that of a flower-producing inflorescence meristem. In Arabidopsis, floral meristems are specified on the periphery of the inflorescence meristem by the combined activities of the FLOWERING LOCUS T (FT)-FD complex and the flower meristem identity gene, LEAFY (LFY). Two redundant functioning homeobox genes, PENNYWISE (PNY) and POUND-FOOLISH (PNF), which are expressed in the vegetative and inflorescence SAM, regulate patterning events during reproductive development, including floral specification. To determine the role of PNY and PNF in the floral specification network, we characterized the genetic relationship of these homeobox genes with LFY and FT. Results from this study demonstrate that LFY functions downstream of PNY and PNF. Ectopic expression of LFY promotes flower formation in pny pnf plants, while the flower specification activity of ectopic FT is severely attenuated. Genetic analysis shows that when mutations in pny and pnf genes are combined with lfy, a synergistic phenotype is displayed that significantly reduces floral specification and alters inflorescence patterning events. In conclusion, results from this study support a model in which PNY and PNF promote LFY expression during reproductive development. At the same time, the flower formation activity of FT is dependent upon the function of PNY and PNF.