Comparison of Selection Efficiency between the bar and hpt Genes in Agrobacterium-mediated Transformation of Muscari armeniacum

Abstract

Embryogenic calli of Muscari armeniacum cv. Blue Pearl were co-cultivated with Agrobacterium tumefaciens EHA101/pBH, which harbored a binary vector that carries the phosphinothricin acetyltransferase (bar) and hygromycin phosphotransferase (hpt) genes. The calli were then transferred onto the selection media containing either 4 mg · liter⁻¹ bialaphos or 75 mg · liter⁻¹ hygromycin. Four to five weeks after transfer to the selection media, both bialaphos-resistant (Bia^r) and hygromycin-resistance (Hyg^r) cell clusters were produced. Over 90% of callus lines selected on a bialaphos-containing medium were verified to be transgenic by PCR analysis; this selection efficiency is comparable to that based on the hpt gene. Leaf segments of plantlets regenerated from the transgenic Bia^r callus lines showed resistance to 4 mg · liter⁻¹ of bialaphos, indicating that the bar gene is useful not only as a selectable marker but also as a producer of herbicide-resistant transgenic plants of M. armeniacum.