Abstract: | Roots in the soil are illuminated by far‐red (FR) light passed through plant tissues in the daytime, and are in complete darkness at night. To evaluate whether gene expression of roots is affected by a dark‐FR light cycle, gene expression profiles were analysed for dark‐adapted versus light‐grown plants and for FR light‐illuminated versus dark‐adapted plants using the RIKEN Arabidopsis full‐length cDNA microarray (containing approximately 7000 independent, full‐length cDNA groups). Among candidate dark‐ and FR‐regulated genes, several were further analysed. Eleven dark‐inducible and five dark‐repressed genes were characterized. Almost all the dark‐inducible and –repressed genes were oppositely regulated by FR light illumination. The functions of dark‐ and FR‐responsive genes and the significance of FR light‐regulated gene expression in roots under ground are discussed. |