Submitted to: Functional Plant Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/26/2002
Publication Date: 12/31/2002
Citation: LOPEZ, C.G., BANOWETZ, G.M., PETERSON, C.J., KRONSTAD, W.E. WHEAT DEHYDRIN ACCUMULATION IN RESPONSE TO DROUGHT STRESS DURING ANTHESIS. Functional Plant Biology. 2002. V. 29. P. 1417-1425. Interpretive Summary: The winter wheat (Triticum aestivum L.) producing region of the U.S. Pacific Northwest (PNW) is subject to drought in the fall when wheat is planted and in the summer when grains are maturing. These drought conditions can reduce yields to uneconomical levels for producers and reduce the quality of the wheat. Consequently there is interest in developing new varieties of wheat with improved drought tolerance for the PNW. Identifying easily detectable biochemical markers associated with drought tolerance would accelerate the development of new varieties. This study characterized the expression of dehydrins, a family of proteins that accumulate during drought, in seven varieties of wheat exposed to drought. Differences in the accumulation of one dehydrin were noted that correlated with relative drought tolerance in these wheats. Wheats that accumulated this dehydrin early in the drought had significantly less yield reduction compared to wheats that accumulated the dehydrin later. The specific role of these proteins remains unknown, but their association with stress tolerance suggests that dehydrins will be useful as markers for the development of drought tolerant wheats.
Technical Abstract: The winter wheat (Triticum aestivum L.) producing region of the U.S. Pacific Northwest (PNW) is often subject to water deficits at sowing and during grain filling. Improved genetic adaptation of wheat cultivars to drought stress is one objective of breeding efforts in the region and consequently there is interest in identifying molecular markers associated with drought tolerance. Dehydrins, a family of proteins that accumulate in response to dehydrative stress, may provide a suitable marker for use in breeding programs. Seven cultivars, 'Connie', 'Gene', 'TAM105', 'Rod', 'Hiller', 'Rhode', and 'Stephens', were evaluated in two experiments in which dehydrin accumulation and their association to stress tolerance during grain filling was characterized during progressive drought stress. A 24 kDa dehydrin was present in leaves at each sampling date in all seven cultivars. Quantitative differences in accumulation of this protein were observed between cultivars on the third sampling date (four days of stress). This differential accumulation was associated with stress tolerance characterized by a lower yield reduction and a lowered rate of decrease in leaf water potential in Connie, TAM105, Gene and Stephens. In contrast to leaves, an increased number of dehydrins were observed in grains under stress and non-stress treatments. Despite the number of dehydrins detected, there was no apparent association between drought stress and dehydrin expression in grains. Although the specific role of these proteins remains unknown, their association with stress tolerance suggests that dehydrins have utility in improving adaptation to drought and as markers for drought tolerance.