Expression of early genes in light-induced chloroplast differentiation of cultured plant cells.

The objective of this study was to identify genes, preferentially of the plastid, which are rapidly expressed during the initial phase of blue-light-induced chloroplast development in suspension-cultured cells (Chenopodium rubrum L.) and to analyse the encoded proteins. A cDNA library (lambda gt 10) was constructed using total RNA from plastid preparations of dark-grown cells exposed to blue light for 3, 6 and 12 h. By differential screening, at least three clones were identified which correspond to rapidly light-induced plastid genes. For these and a number of nuclear genes represented by other clones, a temporary accumulation of the specific mRNA was observed between 12 and 48 h of blue-light exposure. With regard to their nucleotide sequence and derived amino-acid sequence they seem to represent a novel group of genes distinctive in structure and encoded product.