Transgenic Eustoma grandiflorum expressing the bar gene are resistant to the herbicide Basta^®

Abstract

Lisianthus (Eustoma grandiflorum) is a cut or ornamental flower that is popular all over the world. This ornamental crop, however, lacks an effective weed control method due to its susceptibility to herbicide. In this study, transgenic plants of a lisianthus cultivar were produced using Agrobacterium-mediated delivery of the plasmid pCAMBIA3300, which carried the bialaphos resistance (bar) gene under driven by the CaMV 35S promoter. The transgenic calli were derived from wounded edges of the leaves grown on a shoot regeneration medium containing 100 mg l⁻¹ cefotaxime and 2 mg l⁻¹ glufosinate ammonium for 4 weeks. The callus that was detached from the wounded edge of the leaf was transferred to the shoot regeneration medium with 100 mg l⁻¹ cefotaxime and 5 mg l⁻¹ glufosinate ammonium for 4 weeks for shoot regeneration. The bar gene integration and expression in the transgenic plants were confirmed by Southern and Northern blot analyses, respectively. Subsequently, the transgenic lines were assessed in vitro and under greenhouse conditions for their resistance to the commercial herbicide Basta^®, which contains glufosinate ammonium as the active component. Six transgenic lines showed high percentages (67–80%) of survival in vitro under the selection condition with glufosinate ammonium (up to 216 mg l⁻¹). Under greenhouse conditions, the plants from these six lines remained healthy and exhibited a normal phenotype after spraying with glufosinate ammonium (up to 1,350 mg l⁻¹). This is the first paper to provide a detailed survey of transgenic lisianthus expressing the bar gene and exhibiting herbicide-resistance under greenhouse conditions.