Biolistic mediated sorghum (sorghum bicolor L. Moench) transformation via mannose and bialaphos based selection systems

Abstract

The efficiency of the bialophos (bar) and phosphomannose isomerase (pmi) selectable markers in microprojectile mediated transformation of P898012, a sorghum inbred line generally considered amenable to in vitro manipulation was investigated. Two plasmids containing bar gene, encoding bialaphos resistance and manA gene, for phosphomannose isomerase, both under the control maize ubiquitin promoter and nopaline synthase terminator were used to transform Immature Zygotic Embroys (IZE) of sorghum via particle bombardment using a particle infolw gun. Transgene integration in putatively trangenic plants was confirmed by PCR and Southern blot analysis. The expression of the bar gene in transgenic plants was demonstrated by the BASTA laef painting assay. Present results indicated a transformation efficiency of 0.11% and 75% escapes in the apparent bialaphos resistant plants. A transformation efficiency of 0.77% was observed on manA selection and all plants recovered contained the manA gene. Besides an improved transformation efficiency, mannose selection offers a more environmentally sound system as sugar metabolism is considered ecologically neutral should it inadvertently be transformed to wil sorghum species.