Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2005
Publication Date: 12/27/2005
Citation: Park, S., Li, J., Pittman, J.K., Berkowitz, G.A., Yang, H., Undurraga, S., Morris, J., Hirschi, K.D., Gaxiola, R.A. 2005. Up-regulation of a H(+)-pyrophosphatase (H(+)-PPase) as a strategy to engineer drought-resistant crop plants. Proceedings of the National Academy of Sciences. 102(52):18830-18835. Interpretive Summary: The goal of this project is to make more robust tomatoes during conditions where water is not available. In order to do this, we have manipulated genes in the tomatoes to produce more substantial root growth. These plants with better roots are substantially more tolerant to water deficit. These findings document a general strategy for improving drought resistance in crops. This will aid in overcoming food shortages through self-reliance.
Technical Abstract: Engineering drought-resistant crop plants is a critically important objective. Overexpression of the vacuolar H(+)-pyrophosphatase (H(+)-PPase) AVP1 in the model plant Arabidopsis thaliana results in enhanced performance under soil water deficits. Recent work demonstrates that AVP1 plays an important role in root development through the facilitation of auxin fluxes. With the objective of improving crop performance, we expressed AVP1 in a commercial cultivar of tomato. This approach resulted in "(i)" greater pyrophosphate-driven cation transport into root vacuolar fractions, "(ii)" increased root biomass, and "(iii)" enhanced recovery of plants from an episode of soil water deficit stress. More robust root systems allowed transgenic tomato plants to take up greater amounts of water during the imposed water deficit stress, resulting in a more favorable plant water status and less injury. This study documents a general strategy for improving drought resistance of crops.