Microarray Analysis for the Screening of Genes Inducible by Light or Low Temperature in Post-veraison Grape Berries

Flavonoid biosynthesis in grape (Vitis spp.) berry skin is affected by environmental factors such as light and temperature. However, the components of the light signaling and low-temperature-induced abscisic acid (ABA) signaling networks related to flavonoid accumulation in grape berry skin have not been fully elucidated, and how environmental conditions affect these components remains unclear. To clarify the details of the possible light- and ABA-related signal transduction networks, we developed a grape oligo-DNA microarray (38,549 independent probes) using the publicly available genomic sequence of grape, and performed comprehensive transcriptome analysis using detached 'None' grape (Vitis labruscana x V. vinifera) berries cultured under different light and temperature conditions. Using the microarray data, we explored the light-inducible and low-temperature-inducible genes in post-veraison grape berries. We identified 40 light-inducible genes, 55 low-temperature-inducible genes, and 34 genes induced by light plus low temperature. Among these, we selected elongated hypocotyl 5 (HY5), open stomata 1 (OST1), and enhanced response to ABA I (ERA1) as candidate light-inducible, low-temperature-inducible, and light- plus low-temperature-inducible genes, respectively. We investigated their detailed expression characteristics in grape accessions by means of quantitative real-time polymerase chain reaction analyses, and hypothesized that HY5, OST1, and ERA1 might be involved in flavonoid biosynthesis via light signaling and low-temperature signaling networks. We also established an extensive catalog of gene expression patterns to support future investigations of other candidate genes that respond to light and temperature in grape berry skin.