GENOTYPIC COMPARISON OF HEAT-SHOCK PROTEIN-SYNTHESIS IN SORGHUM

High temperature stress is an environmental factor limiting sorghum (Sorghum bicolor (L.) Moench) productivity. We determined the optimum heat-shock protein (HSP) induction temperature in sorghum leaves and investigated intraspecific genetic variability in HSP synthesis among inbred lines RTx430, SC599-6, and SC326-6. One dimensional electrophoresis indicated an optimum 42-degrees-C synthesis temperature in seedling leaves. Analysis of genetic variation by two-dimensional electrophoresis showed only three genotype-specific but many common HSPs. Sixteen of the common HSPs were synthesized in control samples; however, synthesis during high temperatures was dramatically enhanced. The results suggest limited variation in HSP synthesis and predominant constitutive HSP synthesis among these sorghum lines.