Overexpression of radish (Raphanus sativus) defensin gene (RsAFP1) in canola (Brassica napus) improves resistance to Sclerotinia stem rot disease

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the major fungal diseases in canola (Brassica napus). Using new genetic engineering methods to target useful genes transition in plants can promise substitution of chemical control methods. Defensins are antimicrobial peptides which cause permeabilization of fungal membranes, leading to the inhibition of fungal growth and can be an appropriate candidate for transformation. In this study, a radish (Raphanus sativus) defensin gene (Rs-AFP1) from was cloned to pBI121expression vector under CaMV35S promoter. The recombinant construct (pBINZP1) was transferred to canola through Agrobacterium-mediated method. Putative transgenic plants of T0 generation were confirmed by polymerase chain reaction and Southern blot analysis. The transformation frequency obtained 4.2% and the copy numbers of integrated transgenes into transgenic plants genome ranged between 1–3 copies. The antifungal activities of single copy transgenic plants in T0 generation and homozygous transgenic plants in T2 generation were studied by In vitro bioassays and greenhouse assay, respectively. The results showed that over expression of defensin in transgenic canola improved resistance to this fungal pathogen compared to untransformed plants.