Heat shock of wheat during grain filling: Proteins associated with heat-tolerance

Two complementary approaches were used to determine the effects of heat shock on wheat-grain quality. Heat-susceptibility (cv. Wyuna) and heat-tolerant (cv. Fung) cultivars of wheat were compared after heat shock, utilising both dough-quality testing and proteome analysis. Plants were grown at day/night temperatures of 24/18degreesC during development, with stressed plants being subjected to heat shock at day/night temperatures of 40/25degreesC on 15, 16 and 17 days post-anthesis. Grain samples were taken at development (17 days post-anthesis) and at maturity (45 days post-anthesis). Dough-quality testing of flour indicated that the Wyuna cultivar exhibited a decrease in dough strength after heat shock whilst fang cultivar exhibited an increase. Proteome studies conducted on endosperm (at 17 days post-anthesis) showed that the heat-tolerant Fang cultivar exhibited exhibited a stronger and more diverse 'heat shock response' that Wyuna. In total, 48 protein spots exhibiting differential expression between control and heat shock treatment were excised from gels and analysed by mass spectrometry. The resultant tryptic-peptide mass fingerprint data was submitted to SWISS-PROT and TrEMBL databases for protein identification. The majority of heat-shock proteins were expressed in heat shocked Fang but did not in heat shocked Wyuna, thus were further characterised breeders in the selection of heat-tolerant cultivars that would not be expected to lose dough strength in such and environment. (C) 2002 Elsevier Science Ltd.