A putative cold shock protein-encoding gene isolated from Arthrobacter sp. A2-5 confers cold stress tolerance in yeast and plants

Abstract

A putative cold shock protein gene, designated as ArCspA, was isolated from Arthrobacter sp. A2-5 extracted from soil at the South Pole. The ArCspA gene is 873 nucleotide bp long and includes a 207-bp short open reading frame (ORF) with 49.3–92% amino acid identity to peptide sequences of other bacterial cold shock proteins. Northern blot analysis revealed that ArCspA was highly expressed at low temperatures. Bio-functional analysis using ArCspA-overexpressed transgenic Saccharomyces cerevisiae showed that ArCspA conferred cold tolerance on yeast at low temperatures (15°C). We then developed an ArCspA-overexpressed transgenic tobacco line to determine whether ArCspA is also functional in plants. After cold treatment at −25°C for 90 min followed by recovery for 4 weeks at 25°C, 17 transgenic lines survived at a high rate (60.0%), whereas under the same treatment conditions, wild-type plants did not survive. We also found that progeny of transgenic tobacco plants subjected to freezing stress at −20°C had significantly higher seed germination ability than wild-type plants. These results clearly indicate that the ArCspA protein plays an important role in cold tolerance in both yeast and plants.