Abstract
For molecular genetics of plant organogenesis de novo, we have isolated and analyzed many temperature-sensitive mutants of Arabidopsis that are impaired in adventitious root formation. One of these mutants, rid2, exhibits a temperature-dependent defect in the initial phase of adventitious root formation, probably at the process of the resumption of cell division. Positional cloning of the RID2 gene revealed that it encodes a methyltransferase-like protein containing an S-adenosylmethionine-binding motif and a nuclear localization signal. When hypocotyl explants were induced to form adventitious roots by auxin treatment, the RID2 mRNA accumulated within the first 12 hours, which is consistent with the phenotype of the rid2 mutant. Reporter analysis with RID2pro::GUS indicated that the RID2 gene is highly expressed in the subapical region of the primary root and lateral root primordia.
