Heat tolerance and expression of protein synthesis elongation factors, EF-Tu and EF-1α, in spring wheat

Protein elongation factors, EF-Tu and EF-1 alpha, have been implicated in cell response to heat stress. We investigated the expression (accumulation) of EF-Tu and EF-1 alpha in mature plants of spring wheat cultivars Kukri and Excalibur, and tested the hypothesis that cultivars with contrasting tolerance to heat stress differ in the accumulation of these elongation factors under prolonged exposure to high temperature (16 days at 36/30 degrees C). In addition, we investigated the expression of EF-Tu and EF-1 alpha in young plants experiencing a 24-h heat shock (43 degrees C). Excalibur showed better tolerance to heat stress than Kukri. Heat stress induced accumulation of EF-Tu and EF-1 alpha in mature plants of both cultivars, but to a greater extent in Excalibur. Young plants did not show appreciable accumulation of EF-Tu in response to heat shock. However, these plants showed increased accumulation of EF-1 alpha and the accumulation appeared greater in Excalibur than in Kukri. The results support the hypothesis that EF-Tu plays a role in heat tolerance in spring wheat. The results also suggest that EF-1 alpha may be of importance to wheat response to heat stress.