Gene expression during heat-shock in embryogenic carrot cell lines

We have isolated an hsp90 gene from carrot (Daucus carota). The deduced amino acid sequence from this cDNA revealed its similarity to the organelle-type HSP90 protein. It has high homology to other plant organelle-isoforms and shows similar homology to both cytoplasmic and prokaryotic HSP90s. To study the regulation of gene expression during heat-shock, two embryo-specific DC8 and DC59 genes, a tubulin gene and an hsp90 gene were monitored in two embryogenic heat-stressed carrot cell lines. The expression of DC8, a LEA and DC59, an oleosin gene, decreased in both cell lines. In addition, there was a progressive degradation of the accumulated messages with time. The expression of hsp90 gene was induced in both cell lines but with a different pattern of transcript accumulation. These results indicate that the haploid cell line responds differently from the diploid cell line and there is differential transcriptional activity in both cell lines during heat-stress.