Heat shock of cultivated and wild wheats during early seedling stage: growth, cell viability and heat shock proteins

Growth, cell viability and heat shock proteins (HSPs) in Bezostaya-1, Cukurova-86 and Diyarbakir-81 cultivated wheat cultivars and three Aegilops species were investigated. Etiolated seedlings were exposed to 23 degrees C, 32 degrees C, 35 degrees C, 37 degrees C and 38 degrees C for 24 h, and 35 degrees C (24 h) --> 50 degrees C (1 h) and 37 degrees C (24 h) --> (50 degrees C (1 h). At the end of recovery growth periods, the shoot lengths of the genotypes generally decreased significantly at 35, 37 and 38 degrees C. The acquired thermal tolerance (ATT) in intact seedlings was over 50% at 35 degrees C --> 50 degrees C and 37 degrees C --> 50 degrees C, but in cell viability test it ranged from 2.75% (Ae. triuncialis) to 32.87 (Bezostaya-1) at 35 degrees C, and from 2.82% (Ae. triuncialis) to 37.82 (Bezostaya-1) at 37 degrees C. Ae. triuncialis was most sensitive genotype in both ATT determination. In electrophoretic profiles of proteins, while some HSPs were newly synthesized, some normal cellular proteins disappeared at 37 degrees C and 37 degrees C -->50 degrees C compared to 23 degrees C. The number of low molecular weight (LMW) HSPs were more than intermediate- (IMW) and high- (HMW) HSPs. The genotypes had both common (12 HSPs between at least two genotypes) and genotype-specific (33 HSPs) LMW HSPs. The common HSP of 19.8 kDa (pI 6.5) was synthesized in Bezostaya-1, Cukurova-86, Diyarbakir-81, Ae. biuncialis and Ae. umbellulata. Bezostaya-1 is the only genotype that synthesized 12 IMW and 2 HMW HSPs at 37 degrees C --> 50 degrees C. Ae. triuncialis had only two common LMW HSPs 22.1 (pI 7.1) and 24.2 kDa (pI 6.5)].