Abstract
In Arabidopsis, six of NAC transcription factors including RD26 are induced by drought, ABA and high salinity stress. The RD26 transcripts are induced in 30 minutes after the stress treatment and the expression continues to increase for more than 24 hours. However, the protein of RD26 is less accumulated than the transcripts of RD26, which suggests that the level of the RD26 protein may be regulated not only at transcriptional level but also at posttranslational level. Three of RING-type ubiquitin ligases were reported to interact with ANAC, a homolog of RD26 in the yeast two-hybrid system. We found an F box-type ubiquitin ligase that binds to RD26 in yeast. All of these four ubiquitin ligases showed the interaction with RD26 and ANAC by BiFC assay. We report the regulation of the stress-inducible NAC proteins and the functional analyses of these ubiquitin ligases in the ABA-dependent stress-signaling pathway.
