Abstract
To explore basic components of plant morphogenesis, we have isolated and investigated a number of temperature-sensitive mutants of Arabidopsis thaliana that are defective in in-vitro organogenesis. Of these, rid3 (root initiation defective 3), rpd2 (root primordium defective 2), and rgd3 (root growth defective 3) were characterized by being temperature-sensitive for shoot and root redifferentiation while being almost insensitive for dedifferentiation and callus cell proliferation. Analysis of expression patterns of SAM-related genes during shoot redifferentiation revealed that the expression levels of CUC1 and CUC2 are suppressed in the rgd3 explants cultured at restrictive temperature, which might be partially responsible for the defect of shoot redifferentiation in this mutant. Phenotypic analysis of mutant seedlings indicated that the rgd3 mutation also affects the structural maintenance of both SAM and RAM.
Map-based cloning of the responsible genes of these mutants are in progress, and RID3 was found to encode a novel WD40-repeat protein.
