Transgenic durum wheat by microprojectile bombardment of isolated scutella

Abstract

A biolistic transformation method was developed, for the first time, for durum wheat (Triticum turgidum L., 2n = 4x = 28; AABB) cultivar Medora using isolated scutella as target cells, gus as a reporter gene, and bar (herbicide resistance gene) as a selectable marker. An average of 116 GUS foci per scutellum were observed 2 days after bombardment. After selection for herbicide resistance by adding 5 mg/l L-phosphinothricin (L-PPT) to the medium during regeneration and spot application of 120 mg/l L-PPT on the leaves of regenerated plants, we identified five resistant plants from a total of 245 scutella bombarded. All these plants were fertile. Of the 1048 T1 seeds germinated from five lines (dwt1, dwt2, dwt3, dwt4, and dwt5), a total of 104 T1 plants were recovered that showed resistance to the herbicide glufosinate when sprayed at a concentration of 120 mg/l L-PPT. Some of the herbicide-resistant T1 plants exhibited phosphinothricin acetyltransferase (PAT) enzyme activity, indicating the presence of the bar gene in the transgenics. The integration of gus and bar genes into the genomes of durum wheat was further confirmed by Southern analysis. Development of this transformation procedure with an agronomically superior durum cultivar will open up new avenues for the enhancement of the existing germplasm through biotechnology.