Agrobacterium tumefaciens mediated transfer of Phaseolus vulgaris alpha-amylase inhibitor-1 gene into mungbean Vigna radiata (L.) Wilczek using bar as selectable marker

Morphologically normal and fertile transgenic plants of mungbean with two transgenes, bar and α-amylase inhibitor, have been developed for the first time. Cotyledonary node explants were transformed by cocultivation with Agrobacterium tumefaciens strain EHA105 harboring a binary vector pKSB that carried bialaphos resistance (bar) gene and Phaseolus vulgaris α-amylase inhibitor-1 (αAI-1) gene. Green transformed shoots were regenerated and rooted on medium containing phosphinothricin (PPT). Preculture and wounding of the explants, presence of acetosyringone and PPT-based selection of transformants played significant role in enhancing transformation frequency. Presence and expression of the bar gene in primary transformants was evidenced by PCR-Southern analysis and PPT leaf paint assay, respectively. Integration of the Phaseolus vulgaris α-amylase inhibitor gene was confirmed by Southern blot analysis. PCR analysis revealed inheritance of both the transgenes in most of the T₁ lines. Tolerance to herbicide was evidenced from seed germination test and chlorophenol red assay in T₁ plants. Transgenic plants could be recovered after 8–10 weeks of cocultivation with Agrobacterium. An overall transformation frequency of 1.51% was achieved.