Agrobacterium tumefaciens-mediated transformation of Lesquerella fendleri L., a potential new oil crop with rich lesquerolic acid

Abstract

A protocol was developed for regeneration and Agrobacterium-mediated genetic transformation of Lesquerella fendleri. Calli were first induced from hypocotyls and cotyledons on MS plus 0.5 mg l⁻¹ BA, 1 mg l⁻¹ NAA and 1 mg l⁻¹ 2,4-D, then co-cultivated for 2–3 days in darkness on MS supplemented with 0.5 mg l⁻¹ BA, 0.2 mg l⁻¹ NAA and 100 μmol l⁻¹As together with Agrobacterium tumefaciens strain EHA105/pCAMBIA1301 that harbored genes for uidA (GUS) and hygromycin resistance. Following co-cultivation, calli transfected by A. tumefaciens were transferred to MS with 0.5 mg l⁻¹ BA, 0.2 mg l⁻¹NAA, 500 mg l⁻¹ Cef and 10 mg l⁻¹ hygromycin and cultured for 10 days, then the hygromycin was increased to 20 mg l⁻¹ on the same medium. After 4 weeks the resistant regenerants were transferred to MS with 0.5 mg l⁻¹BA, 0.2 mg l⁻¹ NAA, 500 mg l⁻¹ Cef and 25 mg l⁻¹ hygromycin for further selections. Transgenic plants were confirmed by polymerase chain reaction analysis, GUS histochemical assay and genomic Southern blot hybridization. With this approach, the average regeneration frequency from transfected calli was 22.70%, and the number of regenerated shoots per callus was 6–13. Overall results described in this study demonstrate that Agrobacterium-mediated transformation is a promising approach for improvement of this Lesquerella species.