Suppression of late-flowering and semi-dwarf phenotypes in the arabidopsis clock mutant lhy-12;cca1-101 by phyB under continuous light
Suppression of late-flowering and semi-dwarf phenotypes in the arabidopsis clock mutant lhy-12;cca1-101 by phyB under continuous light
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DOI：
10.4161/psb.6.8.16361
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发表时间：
2011-01-01
影响因子：
2.9
通讯作者：
Mizoguchi, Tsuyoshi
中科院分区：
文献类型：
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作者：
Miyata, Kana;Calvino, Martin;Mizoguchi, Tsuyoshi
拟南芥的光周期开花不仅受花激活因子如GI、CO和FT的调控，还受抑制因子如SVP和FLC的调控。LHY和CCA 1（lhy; cca 1）的双突变主要通过GI-CO依赖途径促进短日照下的开花。相反，lhy; cca 1在连续光照（LL）下表现出延迟开花，可能是由于GI-CO独立途径。这种晚花表型被svp、flc和elf 3抑制。然而，SVP、FLC和ELF 3如何介导LHY/CCA 1和开花时间尚不完全清楚。我们发现，lhy; cca 1表现出短下胚轴和叶柄下LL，但这些影响的分子机制尚未阐明。为了解决这些问题，我们使用两种不同的方法，对LL下抑制一种或两种lhy; cca 1表型的突变进行了筛选。我们发现了两个新的突变，一个显性（del 1）和隐性（phyB-2511）phyB等位基因。hy 3 -1、del 1和phyB-2511三个phyB等位基因突变体的开花时间与野生型几乎相同，但比野生型早。在所有三个phyB突变体中，当与晚开花突变co-2和SVPox结合时，观察到类似水平的开花时间加速。而phyB-2511对lhy; cca 1的作用与hy 3 -1或del 1不同。svp-3没有强烈增强phyB-2511或del 1的早花表型。这些结果表明，通过PhyB的光信号可能会影响时钟蛋白下游的因素，控制开花时间和器官伸长。phyB突变对lhy; cca 1依赖的晚开花具有不同程度的影响，这将有助于确定phyB在LL下由lhy; cca 1控制的开花途径中的特定作用。
Photoperiodic flowering in Arabidopsis is controlled not only by floral activators such as GI, CO and FT, but also by repressors such as SVP and FLC. Double mutations in LHY and CCA1 (lhy;cca1) accelerated flowering under short days, mainly by the GI-CO dependent pathway. In contrast, lhy; cca1 showed delayed flowering under continuous light (LL), probably due to the GI-CO independent pathway. This late-flowering phenotype was suppressed by svp, flc and elf3. However, how SVP, FLC and ELF3 mediate LHY/CCA1 and flowering time is not fully understood. We found that lhy; cca1 exhibited short hypocotyls and petioles under LL, but the molecular mechanism for these effects has not been elucidated. To address these questions, we performed a screen for mutations that suppress either or both of the lhy; cca1 phenotypes under LL, using two different approaches. We identified two novel mutations, a dominant (del1) and a recessive (phyB-2511) allele of phyB. The flowering times of single mutants of three phyB alleles, hy3-1, del1 and phyB-2511, are almost the same and earlier than those of wild-type plants. A similar level of acceleration of flowering time was observed in all three phyB mutants tested when combined with the late-flowering mutations co-2 and SVPox. However, the effect of phyB-2511 on lhy; cca1 was different from those by hy3-1 or del1. svp-3 did not strongly enhance the early-flowering phenotypes of phyB-2511 or del1. These results suggest that light signaling via PhyB may affect factors downstream of the clock proteins, controlling flowering time and organ elongation. phyB mutations with different levels of effects on lhy; cca1-dependent late flowering would be useful to determine a specific role for PHYB in the flowering pathway controlled by lhy; cca1 under LL.