Abstract

Photoperiod length induces in temperate plants major changes in growth rates, morphology and metabolism with, for example, modifications in the partitioning of photosynthates to avoid starvation at the end of long nights. However, this has never been studied for a tropical perennial species adapted to grow in a natural photoperiod close to 12 h/12 h all year long.We grew Coffea arabica L., an understorey perennial evergreen tropical species in its natural 12 h/12 h and in a short 8 h/16 h photoperiod, and we investigated its responses at the physiological, metabolic and transcriptomic levels. The expression pattern of rhythmic genes, including core clock genes, was affected by changes in photoperiod. Overall, we identified 2859 rhythmic genes, of which 89% were also rhythmic in Arabidopsis thaliana L. Under short-days, plant growth was reduced, and leaves were thinner with lower chlorophyll content. In addition, secondary metabolism was also affected with chlorogenic acid and epicatechin levels decreasing, and in agreement, the genes involved in lignin synthesis were overexpressed and those involved in the flavanol pathway were underexpressed.Our results show that the 8 h/16 h photoperiod induces drastic changes in morphology, metabolites and gene expression, and the responses for gene expression are similar to those observed in the temperate annual A. thaliana species.Short photoperiod induces drastic changes in gene expression, metabolites and leaf structure, some of these responses being similar to those observed in A. thaliana.

中文翻译：

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阿拉伯咖啡关键代谢途径中的光周期依赖性转录修饰

摘要

光周期的长度在温带植物中引起生长速率，形态和代谢的重大变化，例如，通过改变光合产物的分配来避免在漫长的夜晚结束时的饥饿。然而，从未对适合于全年在近12 h / 12 h的自然光周期下生长的热带多年生物种进行过研究。我们种植了Coffea arabica L.，这是一种在自然12 h / 12下的多年生常绿常绿热带物种h和短时间的8 h / 16 h光周期，我们研究了其在生理，代谢和转录组水平上的反应。包括核心时钟基因在内的节律性基因的表达模式受光周期变化的影响。总体而言，我们确定了2859个有节奏的基因，其中89％也是有节奏的。拟南芥大号。在短时间内，植物生长减少，叶片变薄，叶绿素含量降低。此外，次生代谢也受到绿原酸和表儿茶素水平降低的影响，并且一致地，参与木质素合成的基因被过度表达，而参与黄烷醇途径的基因被低表达。我们的结果表明，光周期诱导了8 h / 16 h形态，代谢产物和基因表达的急剧变化以及对基因表达的响应与一年生温带拟南芥中观察到的相似。短光周期诱导基因表达，代谢产物和叶片结构的急剧变化，其中一些响应相似到在拟南芥中观察到的。