Abstract
5-Bromodeoxyuridine (BrdU), a thymidine analog, has been reported to affect various aspects of development and growth of plants. In tissue culture of Arabidopsis, BrdU show different effects on explants, depending on treatment conditions.
We isolated two BrdU-resistant mutants of Arabidopsis, bro1 and bro2, by screening with a focus on the inhibitory effect of BrdU on hypocotyl dedifferentiation. Chromosome mapping and DNA sequencing detected a missense mutation in a gene encoding RNA-binding protein UBA1a in the bro1 genome and a missense mutation in a gene encoding thymidine kinase in the bro2 genome, to which the BrdU-resistant natures of these mutants might be attributable.
We characterized knockout lines of these genes. In the knockout lines of the BRO1 candidate gene, callus induction from hypocotyls of both homozygous and heterozygous mutants appeared partially resistant to BrdU. In the knockout lines of the BRO1 candidate gene, only homozygous mutants were resistant to BrdU.
