Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2002
Publication Date: 4/30/2003
Citation: LOPEZ, C.G., BANOWETZ, G.M., PETERSON, C.J., KRONSTAD, W.E. DEHYDRIN EXPRESSION AND DROUGHT TOLERANCE IN SEVEN WHEAT CULTIVARS. CROP SCIENCE. 2003. v. 43(2). P. 577-582. Interpretive Summary: The winter wheat (Triticum aestivum L.) producing region of the Pacific Northwest (PNW) U.S. is subject to periods of water deficit because wheat is planted into dry soil in the fall and receives little or no additional rainfall when the seedling emerges. Drought stress at this stage of growth can impact winter survival and subsequent crop yield and consequently represents a cropping risk to wheat producers. In order to reduce this risk, regional wheat breeding programs are attempting to improve the genetic adaptation of wheat to drought stress. The identification of an easily-detected protein associated with improved drought tolerance in wheat seedlings would speed these breeding efforts. One potential biochemical marker for drought tolerance is the family of proteins called dehydrins. We characterized dehydrin accumulation during the exposure of seven cultivars ('Connie', 'Gene', 'TAM105', 'Rod', 'Hiller', 'Rhode', and 'Stephens') to progressive drought stress to learn whether dehydrin expression in these wheats was associated with drought tolerance. We found that the expression of one dehydrin was related to acquistion of drought tolerance in Connie, TAM105, and Gene. Dehydrin expression was significantly delayed in the remaining cultivars which exhibited less tolerance. This dehydrin is easily detected in wheat seedlings and will be helpful in screening wheat germplasm for potential new varieties with drought tolerance.
Technical Abstract: The winter wheat (Triticum aestivum L.) producing region of the Pacific Northwest (PNW) U.S. is subject to periods of water deficit during sowing and grain filling. Improving the genetic adaptation of wheat to drought stress represents a primary objective of regional breeding programs. One biochemical response to dehydrative stress is the accumulation of a family of proteins called dehydrins, which are believed to protect membranes and macromolecules against denaturation. Although previous studies demonstrated the accumulation of dehydrins in drought-stressed wheat, little was known about the relation of dehydrin expression to acquisition of drought tolerance in specific varieties adapted to the PNW. We characterized dehydrin accumulation during the exposure of seven cultivars ('Connie', 'Gene', 'TAM105', 'Rod', 'Hiller', 'Rhode', and 'Stephens') to progressive drought stress in four separate experiments. The objective was to identify differences in the nature or timing of dehydrin expression in these cultivars and to learn whether dehydrin expression was associated with the acquisition of stress tolerance during seedling development. Expression of a 24 kDa dehydrin was observed in Connie, TAM105 and Gene after four days of stress and at subsequent sampling dates while no dehydrins were detected in non-stress control plants . Dehydrin expression was significantly delayed in the remaining cultivars. The presence of this dehydrin was related to acquistion of drought tolerance characterized by a greater maintenance of shoot dry matter production in Connie, TAM105, and Gene. Although the role of these proteins remains unknown, the association with stress tolerance suggests that dehydrins might be used to improve the adaptation to drought.