Poster: Tropisms
Abs #
391: LAZINESS locus is involved in leaf movement and stomatal opening induced by blue light.
Blue light (390-500 nm) induces a wide range of physiological responses. Several responses such as phototropism, stomatal opening, chloroplast relocation, and solar tracking by leaves are thought to maximize photosynthetic light capture and control their growth and development. 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. Stomatal opening is also regulated by osmotic changes in guard cells. The molecular mechanism of blue-light induced leaf movement has remained unknown, although blue-light receptors and the signaling pathway of stomatal opening have become clear in Arabidopsis thaliana. To know the above-mentioned mechanism, we have isolated a slow leaf-movement to blue-light irradiation mutant laziness from model legume plant, Lotus japonicus. The laziness mutant showed a deficiency in blue-light induced leaf movement, although the circadian rhythmic movement was similar to that of the wild-type plant. Furthermore, stomatal opening of the laziness mutant was lacking after blue-light irradiation. We are in the process of positional cloning the LAZINESS locus. The locus was 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 Ljphot1could complement the phenotypes of the blue-light receptor mutant of Arabidopsis partially.
