The FLOWERING LOCUS T gene expression is controlled by high-irradiance response and external coincidence mechanism in long days in Arabidopsis.
The FLOWERING LOCUS T gene expression is controlled by high-irradiance response and external coincidence mechanism in long days in Arabidopsis.
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DOI：
10.1111/nph.18932
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发表时间：
2023-04
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通讯作者：
Nayoung Lee;Yusuke Ozaki;Andrew K. Hempton;Hiroshi Takagi;Savita Purusuwashi;Young Hun Song;Motomu Endo;Akane Kubota;T. Imaizumi
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文献类型：
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作者：
Nayoung Lee;Yusuke Ozaki;Andrew K. Hempton;Hiroshi Takagi;Savita Purusuwashi;Young Hun Song;Motomu Endo;Akane Kubota;T. Imaizumi
在自然长日照条件下，拟南芥成花基因开花位点T（开花位点T， flower LOCUS T， FT）呈双峰表达模式，早晚高峰。这种模式不同于在实验室中观察到的，对其潜在机制知之甚少。太阳光和荧光灯之间的红：远红（R: FR）比例差异导致这种FT模式不匹配。我们发现，在日照R: FR （= c. 1）的条件下，在超过14 h的时间内可以诱导双峰FT表达模式。通过昼夜节律门控实验，我们发现，从下午到第二天早上，R: FR调节光（R: FR比在补充FR的情况下调整为1）的累积暴露需要在早上充分诱导FT。相反，仅在下午晚些时候进行2小时的R: FR调整就足以在黄昏诱导FT。我们发现光敏色素A （phytochrome A, phyA）是早上FT表达所必需的，以响应前一天的R: FR调节。作为这一机制的一部分，我们发现光敏色素相互作用因子7有助于FT调节。我们的研究结果表明，植物介导的高辐照响应和外部巧合机制有助于在自然长日照条件下诱导早晨FT。
In natural long days, the florigen gene FLOWERING LOCUS T (FT) shows a bimodal expression pattern with morning and dusk peaks in Arabidopsis. This pattern differs from the one observed in the laboratory, and little is known about underlying mechanisms. A red : far-red (R : FR) ratio difference between sunlight and fluorescent light causes this FT pattern mismatch. We showed that bimodal FT expression patterns were induced in a day longer than 14 h with sunlight R : FR (= c. 1) conditions. By circadian gating experiments, we found that cumulative exposure of R : FR-adjusted light (R : FR ratio was adjusted to 1 with FR supplement) spanning from the afternoon to the next morning required full induction of FT in the morning. Conversely, only 2 h of R : FR adjustment in the late afternoon was sufficient for FT induction at dusk. We identified that phytochrome A (phyA) is required for the morning FT expression in response to the R : FR adjustment on the previous day. As a part of this mechanism, we showed that PHYTOCHROME-INTERACTING FACTOR 7 contributes to FT regulation. Our results suggest that phyA-mediated high-irradiance response and the external coincidence mechanism contribute to morning FT induction under natural long-day conditions.