Monday, November 5, 2007 - 11:05 AM
72-13

Genetic Engineering of Creeping Bentgrass for Enhanced Drought Tolerance.

Christian Baldwin, Hong Luo, Haibo Liu, Lambert McCarty, Nihal Rajapakse, and Joe Toler. Horticulture, Clemson University, 143 P & A Building, Clemson, SC 29634

Plants contain between 75% and 85% water by weight, and begin to wilt with a minimal decrease in water content (~10%). Thus, water is the primary input required for adequate growth and survival of turfgrasses.  Due to limited water resources available, development of drought resistant turfgrasses has become an important agronomic issue in turfgrass management.  Therefore, the objective of this research is to evaluate and demonstrate the feasibility of genetically engineered salt and drought tolerance in transgenic ‘Penn 4’ creeping bentgrass (Agrostis Palustris) through heterologous overexpression of an Arabidopsis thaliana vacuolar H+-pyrophosphatase.  Two chimeric constructs will be used for plant transformation.  The first construct will be the AVP1 gene overexpression plasmid containing a strong constitutive rice ubiquitin promoter driving the AVP1 gene.  Another construct will contain the rice ubiquitin promoter driving an herbicide glufosinate resistance gene, bar, serving as a selectable marker for selection of transformants after plant transformation.  These two gene constructs will be co-transformed into turfgrass via Agrobacterium-mediated transformation.  Transgenic plants will be selected in the progeny derived from the primary transgenics containing both AVP1 and bar genes to retain those, in which the herbicide glufosinate resistance gene, bar, has been segregated away.  Transgenic plants containing transgene AVP1 will be examined for the levels of expression and enzymatic activities of AVP1, potentially enhanced root growth and tolerance to soil water deficits.