Phytochrome B regulates Heading date 1 (Hd1)-mediated expression of rice florigen Hd3a and critical day length in rice
Phytochrome B regulates Heading date 1 (Hd1)-mediated expression of rice florigen Hd3a and critical day length in rice
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DOI：
10.1007/s00438-011-0621-4
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发表时间：
2011-06-01
影响因子：
3.1
通讯作者：
Shimamoto, Ko
中科院分区：
文献类型：
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作者：
Ishikawa, Ryo;Aoki, Mayumi;Shimamoto, Ko
许多植物需要生物钟和光信息来控制开花的光周期。在长日照植物 (LDP) 拟南芥中，生物钟控制的 CONSTANS (CO) 表达和 CO 蛋白的光稳定性诱导 FT (FLOWERING LOCUS T) 触发开花。在短日照植物 (SDP) 水稻中，CO 直向同源物 Heading date 1 (Hd1) 调节 FT 直向同源物 Hd3a，但 Hd1 对 Hd3a 的调节与拟南芥中的不同。在这里，我们基于这三个互补的发现，报告光敏色素 B (phyB) 介导的 Hd3a 抑制是水稻开花长日照抑制的主要原因。首先，Hd1 的过度表达会导致 SD 条件下开花延迟，并且这种效应需要 phyB，表明光调节 Hd1 对 Hd3a 转录的控制。其次，日照长度的单次延长会随着日照长度的增加而降低 Hd3a 的表达。第三，Hd1 过表达植物中的 Hd1 蛋白水平在光照下不会改变。这些结果还表明 phyB 介导的 Hd3a 表达抑制是水稻临界日长分子机制的一个组成部分。
Many plants require circadian clock and light information for the photoperiodic control of flowering. In Arabidopsis, a long-day plant (LDP), flowering is triggered by the circadian clock-controlled expression of CONSTANS (CO) and light stabilization of the CO protein to induce FT (FLOWERING LOCUS T). In rice, a short-day plant (SDP), the CO ortholog Heading date 1 (Hd1) regulates FT ortholog Hd3a, but regulation of Hd3a by Hd1 differs from that in Arabidopsis. Here, we report that phytochrome B (phyB)-mediated suppression of Hd3a is a primary cause of long-day suppression of flowering in rice, based on the three complementary discoveries. First, overexpression of Hd1 causes a delay in flowering under SD conditions and this effect requires phyB, suggesting that light modulates Hd1 control of Hd3a transcription. Second, a single extension of day length decreases Hd3a expression proportionately with the length of daylight. Third, Hd1 protein levels in Hd1-overexpressing plants are not altered in the presence of light. These results also suggest that phyB-mediated suppression of Hd3a expression is a component of the molecular mechanism for critical day length in rice.