Kubasek W. L., Shirley B. W., McKillop A., Goodman H. M., Briggs W., Ausubel F. M.
Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114.
Plant Cell. 1992 Oct;4(10):1229-1236. doi: 10.1105/tpc.4.10.1229.
Many higher plants, including Arabidopsis, transiently display purple anthocyanin pigments just after seed germination. We observed that steady state levels of mRNAs encoded by four flavonoid biosynthetic genes, PAL1 (encoding phenylalanine ammonia-lyase 1), CHS (encoding chalcone synthase), CHI (encoding chalcone isomerase), and DFR (encoding dihydroflavonol reductase), were temporally regulated, peaking in 3-day-old seedlings grown in continuous white light. Except for the case of PAL1 mRNA, mRNA levels for these flavonoid genes were very low in seedlings grown in darkness. Light induction studies using seedlings grown in darkness showed that PAL1 mRNA began to accumulate before CHS and CHI mRNAs, which, in turn, began to accumulate before DFR mRNA. This order of induction is the same as the order of the biosynthetic steps in flavonoid biosynthesis. Our results suggest that the flavonoid biosynthetic pathway is coordinately regulated by a developmental timing mechanism during germination. Blue light and UVB light induction experiments using red light- and dark-grown seedlings showed that the flavonoid biosynthetic genes are induced most effectively by UVB light and that blue light induction is mediated by a specific blue light receptor.
包括拟南芥在内的许多高等植物在种子萌发后会短暂呈现出紫色花青素色素。我们观察到，由四个类黄酮生物合成基因（PAL1，编码苯丙氨酸解氨酶1；CHS，编码查尔酮合酶；CHI，编码查尔酮异构酶；DFR，编码二氢黄酮醇还原酶）编码的mRNA的稳态水平受到时间调控，在持续白光下生长3天的幼苗中达到峰值。除了PAL1 mRNA的情况外，这些类黄酮基因的mRNA水平在黑暗中生长的幼苗中非常低。使用在黑暗中生长的幼苗进行的光诱导研究表明，PAL1 mRNA在CHS和CHI mRNA之前开始积累，而CHS和CHI mRNA又在DFR mRNA之前开始积累。这种诱导顺序与类黄酮生物合成中生物合成步骤的顺序相同。我们的结果表明，类黄酮生物合成途径在萌发过程中受发育时间机制的协调调控。使用在红光和黑暗中生长的幼苗进行的蓝光和UVB光诱导实验表明，类黄酮生物合成基因最有效地被UVB光诱导，并且蓝光诱导是由特定的蓝光受体介导的。
