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Title: Investigating the role of ABA signaling in wheat drought tolerance

Author
item PAN, WILLIAM - Washington State University
item SCHRAMM, ELIZABETH - Washington State University
item Murphy, Lesley
item Garland-Campbell, Kimberly
item Steber, Camille

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2011
Publication Date: 1/15/2011
Citation: Pan, W., Schramm, E., Murphy, L.R., Garland Campbell, K.A., Steber, C.M. 2011. Investigating the role of ABA signaling in wheat drought tolerance. Meeting Abstract. www.intl-pag.org.

Interpretive Summary:

Technical Abstract: Allohexaploid wheat (Triticum aestivum L.) is one of the three major cereal crops supporting human nutrition. Because wheat is often grown under dryland conditions, it is subject to losses as a result of drought stress. This study examines the role of the plant hormone ABA is wheat responses to water deficit. ABA is a signal sent from the root to the shoot in drying soils that can trigger several adaptive responses to water stress including reduced transpiration due to stomatal closure, increased accumulation of osmoprotectants such as proline or LEA proteins, and increased elongation of the main root at the expense of lateral root growth. Experiments examining several wheat cultivars showed that there is variation for vegetative response to ABA among lines that are considered to be drought tolerant. Data suggest that wheat can employ multiple mechanisms to endure water restriction. One cultivar in particular, 'Alpowa', appears to withstand drought not so much through an increase in transpiration efficiency, as through having plant architecture and developmental patterns that are well-suited to the dry environments of eastern Washington. To evaluate the role of ABA specifically in wheat drought responses, we identified mutants with altered response to ABA during seed germination, and then examined the effects these mutants on wheat vegetative transpiration efficiency under well water-watered and dry conditions. A subset ABA-hypersensitive mutants showed decreased transpiration both in drying soils and in response to ABA compared to the corresponding wild-types plants. These mutants also resulted in decreased carbon isotope discrimination (a measure of WUE over time) and increased canopy temperature. Thus, it is possible to select wheat with altered ABA responses and to use these mutants to alter vegetative water relations.