Abstract
We selected pst (photoautotrohic salt tolerance) mutant lines of Arabidopsis for revealing the mechanism of salt tolerance (Plant Cell, 11, 1195-1206, 1999). The cDNA macroarray and oligo-microarray were performed for pst2 and wild-type lines grown under a non-stress condition. Higher expression of a transcription factor with bHLH motif in pst2 plants was confirmed by real-time RT-PCR. There was another specie of mRNA produced by alternative splicing under the salt stress. The RACE has clarified that transcription initiation site is single. The salt-induced mRNA retained an intron on C-terminal side among two introns, and stop codon and its subsequent initiation codon in the retained region generated the two peptide molecules which looked like cleaved forms of the original protein. Protein species produced in plants have been analyzed by immuno-blotting, and the function of bHLH transcription factor has been examined with its transgenic plants.
