biologia plantarum

Biologia plantarum 43:363-367, 2000 | DOI: 10.1023/A:1026765504374

Effect of Low Temperature on the Protein Metabolism of Wheat Leaves

M.L. Pinedo^1,*, G.F. Hernández¹, R.D. Conde¹, J.A. Tognetti²

¹ Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina e-mail

² Cátedra de Fisiología Vegetal, Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, Balcarce, Argentina

The effect of low temperature on the protein metabolism of wheat primary leaves was examined. In seedlings transferred from 25 to 5 °C, total soluble protein accumulation, in vivo protein synthesis and breakdown, in vitro protein breakdown, and SDS-PAGE profiles of proteinases in gelatine-containing gels were analysed. Leaf protein content increased within a 7-d period (70 % over the initial value) in plants exposed to 5 °C. The fast protein accumulation observed on days 0 - 2 was mainly attributed to a decreased breakdown. In further days, parallelly to a slowdown in the rate of protein accumulation, the leaf proteolytic activity increased. The incubation temperature also had an influence on the proteolytic activity: Q ₁₀ values for the 15 - 5 °C range were 80 - 200 % higher than those observed for the 25 - 15 °C range. On the other hand, the in vivo protein synthesis capacity, at either 25 or 55 °C, was not significantly modified in cold-treated plants. In addition to the enhanced activities of two serine-proteinases (previously found in control plants by SDS-PAGE analysis), cold-treated plants displayed a new proteinase, which had not been detected so far.

Keywords: chilling; proteases; protein synthesis; protein degradation; Triticum aestivum L.

Subjects: chilling, protein metabolism; proteases, low temperature, wheat; protein metabolism, low temperature; temperature, low, protein metabolism; Triticum aestivum; wheat, protein metabolism, low temperature

Published: September 1, 2000  Show citation