Polycomb-Group Proteins and FLOWERING LOCUS T Maintain Commitment to Flowering in Arabidopsis thaliana
Polycomb-Group Proteins and FLOWERING LOCUS T Maintain Commitment to Flowering in Arabidopsis thaliana
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DOI：
10.1105/tpc.114.123323
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发表时间：
2014-06-01
期刊：
影响因子：
11.6
通讯作者：
Schubert, Daniel
中科院分区：
文献类型：
--
作者：
Mueller-Xing, Ralf;Clarenz, Oliver;Schubert, Daniel
从营养生长到生殖生长的转换是极其稳定的，即使植物只短暂地暴露在触发开花的环境刺激下。在光周期途径中，由拟南芥开花基因T(FT)编码的一种可移动信号--成花素诱导开花。由于叶片中的FT活性在短暂的光周期诱导后不能保持，因此稳定花承诺的分子基础尚不清楚。在这里，我们证明了多梳蛋白(Pc-G)，它介导了表观遗传基因的调节，在花诱导后维持了花序和花分生组织的一致性。因此，Pc-G活性降低的植株在非诱导条件下茎生叶显著增加，当从诱导条件转移到非诱导条件时，花回复。这些表型几乎完全被开花基因C(FLC)的丢失和营养阶段的缩短所抑制，这两者都推迟了开花，并促进了营养枝的同一性。在Pc-G突变体中，FLC的上调导致花序中FT表达的显著降低。我们发现，FT的这种活动是必要的，以防止花朵倒退。总而言之，我们的结果表明，花分生组织的特性至少部分地由FT的非日长独立作用维持，其表达是由Pc-G活性间接维持的。
The switch from vegetative to reproductive growth is extremely stable even if plants are only transiently exposed to environmental stimuli that trigger flowering. In the photoperiodic pathway, a mobile signal, florigen, encoded by FLOWERING LOCUS T (FT) in Arabidopsis thaliana, induces flowering. Because FT activity in leaves is not maintained after transient photoperiodic induction, the molecular basis for stable floral commitment is unclear. Here, we show that Polycomb-group (Pc-G) proteins, which mediate epigenetic gene regulation, maintain the identity of inflorescence and floral meristems after floral induction. Thus, plants with reduced Pc-G activity show a remarkable increase of cauline leaves under noninductive conditions and floral reversion when shifted from inductive to noninductive conditions. These phenotypes are almost completely suppressed by loss of FLOWERING LOCUS C (FLC) and SHORT VEGETATIVE PHASE, which both delay flowering and promote vegetative shoot identity. Upregulation of FLC in Pc-G mutants leads to a strong decrease of FT expression in inflorescences. We find that this activity of FT is needed to prevent floral reversion. Collectively, our results reveal that floral meristem identity is at least partially maintained by a daylength-independent role of FT whose expression is indirectly sustained by Pc-G activity.