CRYPTOCHROME2 in vascular bundles regulates flowering in Arabidopsis
CRYPTOCHROME2 in vascular bundles regulates flowering in Arabidopsis
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DOI：
10.1105/tpc.106.048157
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发表时间：
2007-01-01
期刊：
影响因子：
11.6
通讯作者：
Nagatani, Akira
中科院分区：
文献类型：
--
作者：
Endo, Motomu;Mochizuki, Nobuyoshi;Nagatani, Akira
植物充分利用光信号来决定开花的时间。在拟南芥中，蓝色/UV-A光感受器隐花色素2(Cry2)和红色/远红光感受器光敏色素B(PhyB)是控制开花的两个主要光感受器。调节开花的光刺激是由叶片感知的。我们最近的研究表明，在叶肉中而不是在维管束中，PhyB的表达抑制了维管束中关键的开花调节基因--开花基因T(FT)的表达。在这项研究中，我们询问了Cry2在叶片中的哪里感知光刺激来调节开花。为了回答这个问题，我们建立了Cry2-绿色荧光蛋白(GFP)融合基因在器官/组织特异性启动子控制下表达的转基因拟南芥品系。对这些品系的分析表明，Cry2-GFP在维管束中的表达挽救了晚花表型，而在表皮或叶肉中没有表达。我们进一步证实，在维管束中表达的Cry2-GFP只增加了维管束中的FT表达。因此，与PhyB形成鲜明对比的是，Cry2很可能以细胞自主的方式调节FT的表达。
Plants make full use of light signals to determine the timing of flowering. In Arabidopsis thaliana, a blue/UV-A photoreceptor, CRYPTOCHROME 2 (cry2), and a red/far-red photoreceptor, PHYTOCHROME B ( phyB), are two major photoreceptors that control flowering. The light stimuli for the regulation of flowering are perceived by leaves. We have recently shown that phyB expression in mesophyll but not in vascular bundles suppresses the expression of a key flowering regulator, FLOWERING LOCUS T ( FT), in vascular bundles. In this study, we asked where in the leaf cry2 perceives light stimuli to regulate flowering. To answer this question, we established transgenic Arabidopsis lines in which the cry2-green fluorescent protein (GFP) fusion was expressed under the control of organ/tissue-specific promoters in a cry2-deficient mutant background. Analysis of these lines revealed that expression of cry2-GFP in vascular bundles, but not in epidermis or mesophyll, rescued the late flowering phenotype. We further confirmed that cry2-GFP expressed in vascular bundles increased FT expression only in vascular bundles. Hence, in striking contrast with phyB, cry2 most likely regulates FT expression in a cell-autonomous manner.