Submitted to: Hereditas
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/31/2001
Publication Date: 12/31/2001
Citation: LOPEZ, C.G., BANOWETZ, G.M., PETERSON, C.J., KRONSTAD, W.E. DIFFERENTIAL EXPRESSION OF A 24-KD DEHYDRIN IN WHEAT SEEDLINGS CORRELATES WITH DROUGHT STRESS TOLERANCE AT GRAIN FILLING. HEREDITAS. 2001. v. 135. p. 175-181. Interpretive Summary: The winter wheat (Triticum aestivum L.) producing region of the U.S. Pacific Northwest (PNW) is affected by drought in the fall when winter wheat is planted and in the summer during grains maturation. Drought reduces yields and consequently, profitability for producers and lowers end-use quality of the wheat. New wheat varieties adapted to drought conditions in the PNW are needed. Development of new varieties would be accelerated by identifying a molecular marker that was readily detected in wheat seedlings. A potential maker was identified in this study, a 24-Kd dehydrin protein. We found that this protein accumulates earlier in wheat varieties that have some degree of drought tolerance when these varieties are subjected to drought.
Technical Abstract: The Pacific Northwest (PNW), an important wheat producing region, is often subject to water deficits during sowing and grain filling. These deficits reduce the quality and yield of the crop. As a consequence, an important objective of breeding programs in the region is improving the genetic adaptation of wheat cultivars to drought stress. Breeding efforts rely on understanding the physiological mechanisms that enhance tolerance to drought stress. One response to dehydrative stresses is the accumulation of proteins called dehydrins, believed to protect membranes and macromolecules against denaturation. We characterized dehydrin accumulation during drought stress and its correlation with stress tolerance during grain filling in seven wheat cultivars, 'Connie', 'Gene', 'TAM105', 'Rod', 'Hiller', 'Rhode', and 'Stephens'. A 24-kDa dehydrin accumulated in seedlings under stress, but not in irrigated control plants. Connie,TAM105, and Gene started to accumulate dehydrins at the fourth day of stress, while the other cultivars showed dehydrins after twelve days of stress. This differential accumulation in seedlings was associated with stress tolerance at grain filling, characterized by a lower reduction in yield and in the rate of decrease in leaf water potential per day of stress. Connie, TAM105, Gene and Rod where the most tolerant cultivars. Results indicate that expression of this 24-kDa dehydrin might serve as a rapid and nondestructive screening technique at the seedling stage. Even though the results are promising, selection experiments using a population segregating for stress tolerance are needed to test more conclusively if this dehydrin can serve as a genetic marker for cultivars with tolerance to drought stress.