Abstract:

To further study the detoxification mechanism of heavy metal-associated isoprenylated plant proteins under heavy metal stress, the cloning of BvHIPP24 gene and its function analysis in yeast under cadmium stress were conducted. The energy sugar beet was used as material and BvHIPP24 gene was cloned by RT-PCR. BvHIPP24 gene was analyzed by bioinformatics. The recombinant plasmid pYES2-BvHIPP24 was constructed using yeast expression vector and transformed into Saccharomyces cerevisiae InVSc1, and the response of BvHIPP24 gene to cadmium stress was studied in eukaryotic yeast cells. Bioinformatics analysis showed that the CDS of BBvHIPP24 gene was 444 bp, encoding 147 amino acids. Its protein molecular weight was 16377.34 Da, and isoelectric point was 9.39. It was a hydrophilic protein, which did not contain transmembrane region and was located in chloroplasts. Conservative domain analysis showed that the gene had a HMA domain. The analysis of phylogenetic tree showed that BvHIPP24 protein and BvHIPP23 protein in energy sugar beet had a close relationship. Under 0.5 mmol/L CdCl₂ stress, compared with the control strain, the recombinant bacteria expressing BvHIPP24 had a significantly better growth trend, and had relatively higher Cd tolerance. These results indicate that BvHIPP24 gene in energy sugar beet plays an important role in detoxification under cadmium stress, and might be involved in the process of cell heavy metal ion absorption, transport and metabolic balance directly or indirectly.

Key words: energy sugar beet, heavy metal-associated prenylated plant protein, cadmium stress, yeast, functional analysis