Abstract
In leguminous plants, beyond the circadian rhythmic movements of their leaves, blue-light irradiation induces changes in turgor pressure of the pulvinar motor cells and leaf movement. The molecular mechanism of blue-light induced leaf movement has remained unknown, although blue-light receptors and the signaling pathway have become clear in Arabidopsis thaliana. To know the above-mentioned mechanism, we have isolated a Lotus japonicus mutant showing a slow leaf-movement to blue-light irradiation, laziness. laziness was also a stomatal-opening defective mutant. We are in the process of positional cloning the LAZINESS locus. The LAZINESS locus was positioned to the upper arm of chromosome 5 and not linked to Lotus CRYPTOCHROMEs (LjCRYs) and PHOTOTROPINs (LjPHOTs), which loci encode blue-light receptors in Arabidopsis. Functional analysis of LjCRYs and LjPHOTs in Arabidopsis transgenic plants showed LjCRYs and LjPHOT1 could complement the phenotypes of the blue-light receptor mutant of Arabidopsis partially.
