Enhanced genetic transformation efficiency of mungbean by use of primary leaf explants

Abstract

Transgenic mungbean plants [Vigna radiata (L.) Wilczek] were developed via genetic transformation of primary leaf explants with disarmed Agrobacterium tumefaciens strain C-58 harbouring a binary plasmid, pCAMBIA-1301 [(containing genes for β-glucuronidase (GUS) and hygromycin phosphotransferase (hpt)]. A genotype independent, high frequency plant regeneration protocol was initially developed with a survival of about 90% in two cultivars of mungbean by use of primary leaf explants (cut at the node) from four-day-old and ten-day-old seedlings. The co-cultivated explants (taken from ten-day-old seedlings of the cultivar K-851) were cultured on hygromycin selection to recover putatively transformed plants, which were acclimatized and moved to the glasshouse. The time required for regeneration of transgenic plantlets from the transformed explants was nearly 12 weeks. The transformed plants were morphologically similar to the seed-germinated plants. Transformation was confirmed by histochemical assay for GUS activity. Stable integration of the marker gene in the TO transgenics and its inheritance in the T1 transgenics has been confirmed through molecular analysis. The enhanced genetic transformation efficiency obtained presently is repeatable and can be used to mobilize genes of agronomic importance into elite cultivars of mungbean.