Total RNA was extracted from leaves sampled at various times of day and pooled to construct a cDNA library using the Clontech SMART system (Clontech laboratories, CA, USA). Levels of cDNA in the library were equalised among genes with a Trimmer-2 cDNA normalisation kit (Evrogen, Moscow, Russia), which prevents recurrent sequencing of abundant cDNAs and increases the efficiency of sequencing. A 454 library was prepared from the cDNA after equalisation using GS Titanium Rapid Library Preparation kit (Roche). This library was sequenced twice by a 454 GS Junior sequencer.