Engineering Resistance Against Barley Yellow Dwarf Virus (bydv) by Expression of The Virus Derived Gene(s) in a Model Plant

Abstract

Barley yellow dwarf viruses [BYDV; genus Luteovirus; family Luteoviridae] are plant-infecting viruses that cause serious economic losses in cereals. Introduction of virus-derived gene(s), through genetic engineering, is considered as a powerful tool to confer resistance. The present study was designed to optimize Agrobacteriummediated plant transformation protocol, with a sense coat protein (CP) gene of BYDV, and to attain transgenic resistance. Briefly, BYDV-CP was amplified, cloned and sequenced from a leaf sample showing leaf discoloration and dwarf stature – symptoms typical of BYDV infection. The CP was sub-cloned into a binary plasmid vector (pING71), in sense orientation. Agrobacterium tumefaciens was used to transform both Nicotinana benthamiana and wheat cv. Bobwhite. Although literature suggests, N. benthamiana genotype used in this study, however could not host aphids for the virus transmission. Similarly, the transgenic Bobwhite could not be tested for resistance due to limited study duration at McGill University, Canada. To come up with, a protocol was optimized to transform an elite wheat variety (Sehar-2006) using different nutrient media concentrations including salts and vitamins. The BYDV-CP transgenes were selected on the antibiotic and confirmed through PCR and reverse transcription PCR. The BYDV-CP transgenic wheat plants were challenged with the BYDV, using viruliferous aphids. The transgenic wheat plants showed mild symptoms, when compared with non-transgenic controls. Our results indicated that the transgenic wheat (Sehar-2006), in general, was good in providing protection against BYDV, grown under greenhouse conditions. The thesis may contribute significant knowledge to validate protection using virus-derived gene and to optimize Agrobacterium-mediated wheat transformation.