Stable Production of Transgenic Pepper Plants Mediated by Agrobacterium tumefaciens

Abstract

The aim of this study was to establish a stable transformation method for hot pepper using the hygromycin phosphotransferase ( hpt )/hygromycin selection strategy. Explants from aseptic pepper seedlings were inoculated with Agrobacterium tumefaciens carrying pCAMBIA1301. A number of calli were developed on the medium containing hygromycin to discriminate the induction of “false-positive buds,” and then shoots were successfully regenerated from the hygromycin-resistant calli. Southern and Northern hybridization analysis indicated that the hpt gene was integrated and expressed in the transgenic pepper plants (T 0 ) and transmitted to the progeny (T 1 ) without genetic modification. Most T 1 progenies derived from self-pollination revealed a 3:1 segregation ratio for hygromycin resistance, indicating that one copy of the T-DNA was integrated into the respective transgenic lines. Both uid A and hpt genes were stably expressed in the T 1 generation and coinherited in the progenies. Finally, homozygous progenies were identified in the T 1 generation of the transgenic peppers, and the homozygous state was maintained in all progenies tested (T 2 ). The results show the reliability and stability of the hpt /hygromycin selection protocol for pepper transformation.