Genomic and physiological studies of early cryptochrome 1 action demonstrate roles for auxin and gibberellin in the control of hypocotyl growth by blue light
Genomic and physiological studies of early cryptochrome 1 action demonstrate roles for auxin and gibberellin in the control of hypocotyl growth by blue light
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DOI：
10.1046/j.1365-313x.2003.01870.x
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发表时间：
2003-10-01
期刊：
影响因子：
7.2
通讯作者：
Spalding, EP
中科院分区：
文献类型：
--
作者：
Folta, KM;Pontin, MA;Spalding, EP
蓝光抑制黄化拟南芥下胚轴的伸长在第一个30分钟的照射的机制，依赖于光致蛋白1（phot 1）感光器。隐花色素1（cry 1）光感受器开始发挥控制30分钟后。要确定基因负责cry 1生长抑制阶段，cry 1和野生型幼苗的mRNA表达谱进行了比较，使用DNA微阵列。在cry 1反应开始时发现的大约420个差异表达的基因中，相对于野生型，大约一半在cry 1中表达更高，一半表达更低。许多cry 1依赖基因编码激酶、转录因子、细胞周期调节因子、细胞壁代谢酶、赤霉酸（GA）生物合成酶和生长素反应因子。高分辨率的生长研究支持了这一假设，即后两类基因确实与cry 1介导的生长控制有关。用3 β-羟化酶抑制剂（Ca-调环酮）抑制GA（4）的生物合成恢复了cry 1的野生型反应动力学，并完全抑制了其在蓝光下的长下胚轴表型。用Ca-调环酮加GA（4）共处理cry 1幼苗完全逆转了抑制剂的作用，恢复了突变体典型的长下胚轴表型。用GA（4）处理野生型幼苗不足以复制cry 1幼苗的表型，但用IAA和GA（4）共处理产生了类似cry 1的生长动力学，持续约5 h。基因组和生理数据一起表明，蓝光通过cry 1快速影响许多基因的表达，其中一个子集通过抑制GA和生长素水平和/或敏感性来抑制茎生长。
Blue light inhibits elongation of etiolated Arabidopsis thaliana hypocotyls during the first 30 min of irradiation by a mechanism that depends on the phototropin 1 (phot1) photoreceptor. The cryptochrome 1 (cry1) photoreceptor begins to exert control after 30 min. To identify genes responsible for the cry1 phase of growth inhibition, mRNA expression profiles of cry1 and wild-type seedlings were compared using DNA microarrays. Of the roughly 420 genes found to be differentially expressed at the point of cry1 response incipience, approximately half were expressed higher and half lower in cry1 relative to the wild type. Many of the cry1-dependent genes encoded kinases, transcription factors, cell cycle regulators, cell wall metabolism enzymes, gibberellic acid (GA) biosynthesis enzymes, and auxin response factors. High-resolution growth studies supported the hypothesis that genes in the last two categories were indeed relevant to cry1-mediated growth control. Inhibiting GA(4) biosynthesis with a 3beta-hydroxylase inhibitor (Ca-prohexadione) restored wild-type response kinetics in cry1 and completely suppressed its long-hypocotyl phenotype in blue light. Co-treatment of cry1 seedlings with Ca-prohexadione plus GA(4) completely reversed the effects of the inhibitor, restoring the long-hypocotyl phenotype typical of the mutant. Treatment of wild-type seedlings with GA(4) was not sufficient to phenocopy cry1 seedlings, but co-treatment with IAA plus GA(4) produced cry1-like growth kinetics for a period of approximately 5 h. The genomic and physiological data together indicate that blue light acting through cry1 quickly affects the expression of many genes, a subset of which suppresses stem growth by repressing GA and auxin levels and/or sensitivity.