Integration of RNAi construct into the genome of Cowpea (Vigna unguiculata L.) for resistance to Cowpea Aphid Borne Mosaic Virus (CAMV) and Cowpea Severe Mosaic Virus (CPSMC)

Abstract

Improvement of cowpea for resistance to major pests and viral diseases is impeded by the absence of resistance genes in its genome. Genetic engineering is a suitable tool using which genes of interest could be introduced into the genome of cowpea. In order to generate cowpea plant resistant to CAMV and CPSMC, RNA interference construct that target the  silencing of CAMV coat protein and CPSMC proteinase cofactor genes were successfully inserted and integrated into cowpea using the biolistic gene delivery system.Three transgenic cowpea lines were regenerated from bombardment of 600 embryos with a transformation frequency of 0.5%. Polymerase Chain Reaction (PCR) analysis of all the primary transformed plants (T₀) and T₁ progeny showed the presence of 340 bp fragment amplified by primers COMOPTYF389 within the CPSMV sequence and COMOPOTYR729 within the CABMV sequence indicating successful insertion and integration of the interfering cassette.