Expression of SsBBX24, SsLTP1 and SsCyP genes in S. tuberosum plants subjected to cold treatment. Semi-quantitative RT–PCR of SsBBX24 and EF-1-α transcript abundances (A) and western blot analysis of SsBBX24, SsCyP and SsLTP protein amounts (B) in young leaves of 2-week-old phytotron-grown S. tuberosum plants subjected to cold treatment (4/3 °C, day/night) for 20 min, 2 h and 1, 3 and 7 days. Lane C, control plants grown in vivo in a phytotron at 21/18 °C (day/night). RT–PCR and western blot analyses were performed as described in Materials and methods. The amounts of proteins set for detection of SsBBX24, SsCyP and SsLTP1 were 30, 10 and 40 μg per lane, respectively.