Transformation studies of creeping bentgrass (Agrostis palustris Huds.) using an elm chitinase gene for disease resistance

Creeping bentgrass (Agrostis palustris Huds.) is a major cool season turfgrass species used for golf greens, tees, and fairways. This important turf species is susceptible to a variety of fungal diseases including brown patch (Rhizoctonia spp.). Genetic transformation technology has made it possible to introduce cloned genes into plant genomes for the purpose of conferring disease resistance and other economically important traits. Among the available disease resistance genes, plant chitinase genes have proven effective in delivering fungal resistance in a number of transgenic plants. An effective microprojectile-mediated transformation system was used in our studies to produce transgenic creeping bentgrass (Agrostis palustris Huds.) plants transformed with an Elm Chitinase (HS2) gene. The selectable marker gene bar (phosphinothricin acetyltransferase, PAT) and the nonselectable HS2 gene on separate plasmids were co-introduced into the creeping bentgrass genome, when embryogenic calli of creeping bentgrass were bombarded with tungsten particles coated with DNA of both plasmids. Transgenic plants carrying the HS2 gene were identified from bar gene-transformed plants, which were resistant to the herbicides bialaphos and Ignite TM. A total of eleven HS2 transformed lines were obtained from forty-six independent lines transformed with the bar gene. The frequency of unlinked cotransformation of bar and the HS2 was 23.9%, which was comparable to that of other studies. Expressions of the HS2 gene was detected from some transgenic lines of creeping bentgrass at both the transcriptional and the translational levels. Two of the HS2 expressing lines exhibited enhanced resistance to Rhizoctonia solani.