Phytochrome B in the mesophyll delays flowering by suppressing FLOWERING LOCUS T expression in Arabidopsis vascular bundles
Phytochrome B in the mesophyll delays flowering by suppressing FLOWERING LOCUS T expression in Arabidopsis vascular bundles
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DOI：
10.1105/tpc.105.032342
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发表时间：
2005-07-01
期刊：
影响因子：
11.6
通讯作者：
Nagatani, A
中科院分区：
文献类型：
--
作者：
Endo, M;Nakamura, S;Nagatani, A
光是决定植物从营养生长期向生殖生长期或开花期过渡的最重要的环境因素之一。不仅日照长度，而且光谱也极大地影响开花。附近植被的阴影降低了红光与远红光的比例，并可以引发避荫反应，包括茎的伸长和开花的加速。光敏色素B（phyB）作为这种反应的光感受器。生理学研究表明，叶子可以感知并对阴影做出反应。然而，很少有人知道的机制，参与处理光信号的叶片。本研究利用增强子-捕获系统构建了组织特异性表达phyB-绿色荧光蛋白（GFP）融合蛋白的拟南芥转基因植株。对这些品系的分析表明，叶肉细胞中的phyB-GFP影响开花，而维管束中的phyB-GFP不影响开花。此外，叶肉phyB-GFP抑制了子叶维管束中关键开花调节因子FLOWERLOCUS T的表达。因此，一种新的组织间信号从叶肉到维管束被揭示为一个关键步骤的调控开花phyB。
Light is one of the most important environmental factors that determine the timing of a plant's transition from the vegetative to reproductive, or flowering, phase. Not only daylength but also the spectrum of light greatly affect flowering. The shade of nearby vegetation reduces the ratio of red to far-red light and can trigger shade avoidance responses, including stem elongation and the acceleration of flowering. Phytochrome B (phyB) acts as a photoreceptor for this response. Physiological studies have suggested that leaves can perceive and respond to shade. However, little is known about the mechanisms involved in the processing of light signals within leaves. In this study, we used an enhancer-trap system to establish Arabidopsis thaliana transgenic lines that express phyB-green fluorescent protein (GFP) fusion protein in tissue-specific manners. The analysis of these lines demonstrated that phyB-GFP in mesophyll cells affected flowering, whereas phyB-GFP in vascular bundles did not. Furthermore, mesophyll phyB-GFP suppressed the expression of a key flowering regulator, FLOWERING LOCUS T, in the vascular bundles of cotyledons. Hence, a novel intertissue signaling from mesophyll to vascular bundles is revealed as a critical step for the regulation of flowering by phyB.