Molecular basis of seasonal time measurement in Arabidopsis

摘要: Several organisms have evolved the ability to measure daylength, or photoperiod, allowing them adjust their development in anticipation of annual seasonal changes. Daylength measurement requires integration temporal information, provided by circadian system, with light/dark discrimination, initiated specific photoreceptors. Here we demonstrate that Arabidopsis this takes place at level CONSTANS (CO)1 function. CO is a transcriptional activator accelerates flowering time long days, least part inducing expression FLOWERING LOCUS T (FT)2,3,4,5. First, show precise clock control timing expression, such it high during daytime only critical for daylength discrimination. We then provide evidence activation FT presence light perceived through cryptochrome 2 (cry2) phytochrome A (phyA). conclude an external coincidence mechanism, based on endogenous messenger RNA levels, and modulation function light, constitutes molecular basis regulation Arabidopsis.