ARS | Publication request: Apple root expressed sequence tags (ESTs) responding to water deficit

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: February 18, 2008
Publication Date: July 20, 2008
Citation: Bassett, C.L., Wisniewski, M.E., Baldo, A.M., Korban, S., Gasic, K., Farrell, Jr., R.E. Apple root expressed sequence tags (ESTs) responding to water deficit. HortScience. Vol. 43, pg. 1079. 2008

Technical Abstract: Water availability is frequently the most critical factor limiting plant growth and survival. For crops such as cereals and herbaceous annuals, breeding and/or selecting lines with improved water use efficiency or drought resistance has been a viable option. However, for slow growing perennials and woody plants, this approach is more problematic. One strategy that can aid breeding programs in selecting lines improved for traits that are either difficult or cumbersome to measure is to develop markers closely linked to the traits of interest. Candidate gene markers that are likely to be related to the desirable trait could be used to identify genes associated with drought resistance. To develop a series of candidate ESTs for mapping water use efficiency and drought resistance in apple (Malus x domestica), we conducted preliminary studies to isolate ESTs responsive to drought in 'Royal Gala', a commercially important cultivar. In this study, we used suppression subtractive hybridization (SSH) to identify genes up- and down-regulated in roots of plants exposed to two weeks of severe water restrictions (45% soil water saturation). We identified approximately 30 genes that were up-regulated in response to water deficit and about half that number that were down-regulated. We compared these results to a similar approach taken previously to develop EST libraries from root, bark and leaf material exposed to water deficit conditions. Combining the results of both approaches has allowed us to expand the number of ESTs that respond to water deficit in apple.