Isolation and RNA gel blot analysis of genes that could serve as potential molecular markers for leaf senescence in Arabidopsis thaliana.

Nine cDNAs, representing genes in which the transcripts accumulated in senescent leaves of Arabidopsis thaliana, were isolated by differential display reverse transcription polymerase chain reaction (DDRT-PCR) and the genes were designated yellow-leaf-specific gene 1 to 9 (YLS1-YLS9). Sequence analysis revealed that none of the YLS genes, except YLS6, had been reported as senescence-up-regulated genes. RNA gel blot analysis revealed that the transcripts of YLS3 accumulated at the highest level at an early senescence stage, whereas the transcripts from the other YLS genes reached their maximum levels in late senescence stages. Transcripts of YLS genes showed various accumulation patterns under natural senescence, and under artificial senescence induced by darkness, ethylene or ABA. These expression characteristics of YLS genes will be useful as potential molecular markers, which will enhance our understanding of natural and artificial senescence processes.