Abstract
Light is the most important environmental information for control of development of leaves as major photosynthetic organs. We previously showed that phytochromes signals enhance leaf-blade expansion but suppress petiole elongation. Therefore, we hypothesized that integration between phytochrome signals and intrinsic factors of each organ plays an important role in controlling the organ-specific photomorphogenesis in leaves. To test this hypothesis, we analyzed rot3 and doc1 mutants of Arabidopsis thaliana. We previously reported that ROT3 encodes CYP90C1 that is involved in the brassinosteroid biosynthesis. The rot3 mutant showed a defect in phyB-dependent petiole elongation, but not in growth of hypocotyl and leaf blade. On the other hand, the doc1 mutant, that resembles the rot3 mutant, is believed to affect auxin transport, and analyses of the rot3 doc1 double mutant suggested the genetic interaction of these genes. Genetic relationship between these factors and light signal transduction pathways will be discussed.
