Regulation of a Solanum Double-B box gene

Double B-box zinc finger (DBB) proteins are recently identified plant transcriptional regulators that participate in the response to NaCl-induced stress in arabidopsis. Kiełbowicz-Matuk et al.investigate variations in a Solanum DBB protein, SsBBX24, in S. tuberosum and S. sogarandinum and find evidence of trafficking from the nucleus to the cytosol during the light period. SsBBX24 gene expression exhibits circadian cycling under control conditions, with the highest and lowest abundances of both transcript and protein occurring 8 h and 18 h after dawn, respectively. Low temperature, salinity and polyethylene glycol disturb the circadian regulation of SsBBX24 gene expression at the protein level, and the time of the day modulates the magnitude of SsBBX24 expression in response to high salt concentration. They propose that stress-dependent, post-transcriptional mechanisms alter the regulation by the circadian clock of the amount of SsBBX24 in Solanum.