Dehydrin-like protein expression profiles of maize seedlings during germination, low temperature stress, and genotype

Improving the cold tolerance of early season performance of maize is an important element of agronomic performance in many production areas. Dehydrin or Dehydrin-like proteins may be related to cold tolerance and their roles in chilling tolerance in many plant species have been a major focus of research. This research investigated the disappearance of dehydrin-like proteins in maize genotypes during seed germination and the re-induction of dehydrin-like proteins after the exposure of seedlings to low temperature stress. Inbred lines with putative differences in tolerance to low temperature stress were utilized. The genotypes analyzed were Co255 (cold tolerant), A619 (cold intermediate) and Mo17 (cold sensitive). To achieve these goals, the concentrations of total proteins and boiling soluble proteins of the three genotypes were analyzed in a split plot of a randomized complete block design. The protein profiles were evaluated by discontinuous SDS-PAGE. Dehydrin-like proteins were detected by immuno-blot assay of boiling soluble protein fractions. Dehydrin-like proteins did not disappear during seed germination while the 40kDa dehydrin-like protein of Mo17 disappeared after day 1 (imbibed embryos), the 22kDa dehydrin-like protein remained detectable throughout the course of this study in all genotypes. No re-induction of dehydrin-like proteins due to low temperature stress was found and their profiles were not affected by stress or genotype. This study might be the first to show; 1) dehydrin-like proteins are detectable in root maize 5-day-old seedlings and 6-day-old seedlings in 250C and 2) dehydrin-like proteins profiles in 2 maize genotypes, A619 and Co255. The role of dehydrin-like proteins in cold tolerance and their re-induction following cold stress on a whole plant basis is not conclusively evaluated by this study, especially since only root tissues were used. Dehydrins or dehydrin-like protein expression in different tissues can vary. Because cold tolerance is a complex trait, further investigations regarding the role of DHN in cold tolerance are warranted