Abstract
rid3 and rgd3 are mutants of Arabidopsis that were characterized by being highly temperature-sensitive for organogenesis in vitro while being much less sensitive for dedifferentiation and callus growth. The RGD3 and RID3 genes encode BTAF1 and WD40-repeat protein, respectively.
Here we report the effects of the rid3 and rgd3 mutations on spatial patterns of cell proliferation and expression of the CUC-STM pathway genes during shoot regeneration. After callus was induced to regenerate shoots, cell division ceased and then was reactivated locally in the surface region, resulting in the formation of pre-SAM cell mounds. The rgd3 mutation inhibited cell division reactivation, and the rid3 mutation caused excess unorganized division. These defects were related to the expression level of CUC1. RID3 was expressed outside the cell mounds while RGD3 and CUC1 were expressed at the cell mounds. Based on the results, a fundamental mechanism of SAM neoformation will be discussed.
