Abstract
rid3, rpd2, and rgd3 are mutants of Arabidopsis thaliana that were characterized in vitro by being temperature-sensitive for organogenesis while being almost insensitive for dedifferentiation and callus cell proliferation. Phenotypic analysis indicated that the rid3 and rpd2 mutations inhibit neo-formation of shoot apical meristem (SAM) and root apical meristem (RAM) and that the rgd3 mutation interferes with SAM neo-formation and maintenance of SAM and RAM. RID3 was revealed to encode a WD40-repeat protein, and a TBP-interacting protein gene has been nominated for RGD3. In the course of shoot regeneration after transfer of calli onto shoot-inducing medium, expression levels of CUC and WUS were elevated prior to SAM establishment, and several days later STM expression was increased. The shoot-regeneration-related expression of CUC and STM was suppressed by the rgd3 mutation and enhanced by the rid3 mutation. Analysis of spatial expression patterns of these genes is in progress using reporter lines.
