Abstract
A comparative study of gene expression patterns during different phases of in vitro regeneration of six canola cultivars was conducted in this research. Calli were obtained from shoot meristem explants and grown on MS (Murashige and Skoog) medium, supplemented with auxin and cytokinin for callus initiation, control plants were propagated from seeds. Expression profiling of two metallothionein genes (MTs); namely BnMT1 and BnMT2 at different phases of tissue culture was analyzed using semiquantitative reverse transcription PCR (sqRT-PCR). The results revealed the superior transcripts of BnMT1 over BnMT2 in control plants within all studied canola cultivars. Approximately, all cultivars exhibited dramatic upregulation of BnMT2 in in vitro tissue culture propagated plants at different phases of culture, compared to control plants.
On the contrary, low expression of BnMT1 could be observed in both studied phases of calli initiation. When the six cultivars were compared, BnMT1 transcripts were relatively equal in all cultivars whereas a remarkable differential expression in BnMT2 was recorded according to the origin and pedigree/selection history of canola cultivars. In case of in vitro regenerated plants, responsive variability appeared within cultivars in both BnMT1 and BnMT2 expression profiles. The results showed confirmed correlation between regeneration potential and gene expression patterns of both BnMT1-2 in the studied canola cultivars. Differential expression of MTs genes was exhibited by some cultivars suggesting genotypic differences sensitivity of canola cultivars to in vitro regeneration. These genes also, could therefore be useful as molecular markers for somaclonal variation, particularly in canola.