Response of AVP1-OX Romaine Lettuce to Phosphorus

Crops produced in the desert receive large annual applications of phosphorus (P) fertilizer. However, declining P mineral reserves, erratic fertilizer costs, and concerns about water pollution, have created incentives for improved efficiency.  While we have developed management practices, such as soil and plant tissue testing and improved fertilizer placement, the possibility of genetic modifications to crops for improved fertilizer use efficiency has received little attention.  Recently, it has been shown that over-expression of type I H⁺ -pyrophosphatase AVP1 (AVP, Arabidopsis vacuolar pyrophosphatase) contribute positively to many energetic plant processes including general growth, nutrient acquisition, and stress response.  This genetic modification enhances nutrient uptake by affecting the abundance and activity of the plasma membrane H⁺-ATPase in a manner that correlates with apoplastic pH alterations and rhizosphere acidification. The objective of this project was to evaluate the potential for using AVP1 overexpression (AVP1-OX) modified romaine lettuce (Lactuca sativa) for improved P use efficiency under desert cropping systems.  Greenhouse and field data show that AVP1-OX romaine lettuce outperformed conventional lettuce at all levels of P.