Abstract
We have demonstrated that cryptochrome mediate blue light dependent photomorphogenic responses in rice, such as growth inhibitions of coleoptiles, leaf blades and leaf sheaths. But the blue light signaling mechanism mediated by cryptochrome remains unclear.
To investigate the underlying mechanisms, the blue light-induced changes of gene expression were analyzed by microarray experiments (Agilent rice 44k). Among the blue light-induced genes, we focused on GA2ox genes, which inactivate the active GAs. Individual RT-PCR experiments confirmed that GA2ox genes were induced by blue but not by red light.
Next, we made CRY1a gene-repressed transgenic rice in the cry1b background (cry1a-Rcry1b-1). The cry1a-Rcry1b-1 seedlings responded very weakly to blue light and showed little induction of GA2ox genes by blue light. Thus, cryptochrome dependent induction of GA2ox genes seems to be involved in the blue light-mediated growth inhibition of leaf blade and sheath.
