Soybean is one of the crops most difficult to be manipulated in vitro. Although several soybean marker genes, all the selectable markers used were from bacteria origin. To find suitable selectable marker gene from plant origin for soybean transformation, a mutant acetolactate synthase （ALS） gene from Arabidopsis thaliana was tested for Agrobacterium-mediated soybean embryo axis transformation with the herbicide Arsenal as the selective agent. Transgenic soybean plants were obtained after the herbicide se- lection and the To transgenic lines showed resistance to the herbicide at a concentration of 100 g/ha. ALS enzyme assay of To transgenic line also showed higher activity compared to the wild type control plant. PCR analysis of the T1 transgenic lines confirmed the integration and segregation of the transgene. Taken together, our results showed that the mutant ALS gene is a suitable selectable marker for soybean transformation.
