In vitro assay selection of glyphosate resistance in lettuce

Abstract

Glyphosate-resistant plants of 'South Bay' lettuce (Lactuca sativa L.) were produced by using Agrobacterium tumefaciens containing a plasmid carrying glyphosate oxidase and EPSPS gene. An in vitro assay was performed to determine the sensitivity of 'South Bay' leaf discs and seedling explants to varying glyphosate concentrations. The I50 for glyphosate leaf discs was 53.8 μM and for glyphosate seedlings 7.6 μM. There was a high correlation between the response of leaf discs and seedlings to glyphosate based on dry weight. These findings will allow identification of glyphosate-resistant transformants in an early stage of plant development, saving time and reducing the cost in generating an improved cultivar with the glyphosate resistance trait.