Changes in chloroplast FtsH-like gene during cold acclimation in alfalfa (Medicago sativa)

A cold-induced mRNA for chloroplast FtsH-like protease was identified from c;DNA array analysis of alfalfa mRNA (Medicago sativa L., cv. Rambler). Expression of this gene was analyzed under different light and temperature regimes, Exposing plants to low temperatures or to high light conditions increased the FtsH levels in both mRNA and protein in alfalfa leaves. The cold-induced accumulation of FtsH is not part of a general response to stressful conditions, since no increased accumulation was detected in response to treatment with ABA, NaCl or desiccation, while exposure to high temperature resulted in a reduction in transcript level. The low-temperature induction of FtsH transcript in dark-grown seedlings suggests that low temperature and light independently regulate expression of the gene.