A plant defensin gene from Orychophragmus violaceus can improve Brassica napus resistance to Sclerotinia sclerotiorum

A plant defensin gene, named as Ovd, was cloned from Orychophragmus violaceus (L.) O. E. Schulz and subsequently introduced into Brassica napus genome by Agrobacterium tumefaciens-mediated transformation method in sense and antisense forms under the control of the CaMV 35S promoter. Genomic PCR analysis confirmed the integration of the sense and antisense Ovd into the host genome. Quantitative RT-PCR showed that the expression of Ovd in the sense plant line was stronger than non-transformed plant and antisense plant. The lesion size on detached leaves of the transgenic plants and nontransformed control caused by Sclerotinia sclerotiorum mycelia was examined. Lesion size was reduced in sense transgenic plants compared to nontransformed control (15 20% reduction area), while it was enlarged in antisense transgenic plants compared to nontransformed control (14 20% enlargement). The results showed that the over-expressing transgenic B. napus had higher resistance to S. sclerotiorum.