Abstract
Efficient selection of transgenic plants is essential in plant biotechnology, and development of effective selectable marker systems plays a crucial role, especially as multiple rounds of transformation and gene stacking may require multiple selectable markers. The present study aims to develop and evaluate an enhanced spectinomycin resistance construct to provide robust selection for transformation events. The new construct was compared in multiple plant species to the standard spectinomycin selectable marker gene currently used for soybean transformation and to the neomycin phosphotransferase (nptII) gene that confers kanamycin resistance. In Arabidopsis thaliana, potato, and citrus, the transformation efficiency provided by the enhanced spectinomycin marker was approximately equal to that of kanamycin and considerably better than that observed for the standard spectinomycin marker. In soybean, the enhanced spectinomycin resistance marker preformed as well as the standard spectinomycin gene. These results demonstrate that the enhanced spectinomycin construct provides strong resistance, comparable to kanamycin in multiple species, offering an alternative tool for transgenic plant selection.