Atriplex triangularis is a halophytic relative of spinach which is under investigation by this laboratory for use as a commercial food crop. Halophytic crop plants allow agriculture in salt-contaminated soil or when only saline irrigation water is available. Genetic transformation quickly introduces characteristics into a crop which cannot be obtained by traditional selective-breeding methods. A protocol has been developed for Agrobacterium tumefaciens-mediated transformation and subsequent tissue culture of A. triangularis, adapted from techniqes developed by this laboratory for use with the potential halophytic crop plant Kosteletzkya virginica (Seashore Mallow). This new protocol involves incubating seedling node explants with two-day cultures of A. tumefaciens and using the transformed nodes for micropropagation cultures on agar-based nutrient medium. Histochemical and antibiotic-resistance studies were performed on explants transformed with the p35 GUSint Ti plasmid containing the beta-glucouronidase (GUS) and neomycin phosphotransferase (NPT II) genes. Preliminary results indicate successful transformation of node meristematic tissue leading to the presence and expression of the foreign genes in new shoots. Further tests may more conclusively confirm the presence and expression of these genes.

Key words: Agrobacterium tumefaciens, Atriplex triangularis, genetic transformation, halophyte, micropropagation