Gene expression in plant cell cultures under continuous blue light irradiation of high intensity

Plant cell cultures cultivated in darkness and subsequently irradiated with continuous blue light have the capacity to develop functional chloroplasts from leucoplast like precursors. This process is accompanied by chlorophyll-synthesis and expression of plastid structural genes. The nature of regulatory factors related to the specific gene activation is uncertain and approaches for their evaluation are described. Exemplarily, events connected to the regulation of a blue light induced gene are introduced. The significance as well as a possible interaction of light and phytohormone signal transduction pathways is discussed.