Evaluation of transgenic peanut plants encoding coat protein and nucleocapsid protein genes for resistance to tobacco streak virus and peanut bud necrosis virus.

Abstract

Genetic engineering of peanuts (Arachis hypogaea L.) via genes encoding for coat protein (CP gene) of Tobacco streak virus (TSV) and nucleocapsid protein (NC gene) of a Peanut bud necrosis virus (PBNV) were used to impart concurrent resistance against the stem and bud necrosis diseases. The main objective of this study was to determine whether the CP/NC-mediated resistance strategy could be applied for developing the transgenic peanut plants, by utilizing CP gene of TSV and NC gene of PNBV. The transgenic lines of peanut cv. K-6 were characterised for integration, inheritance and expression of transgenes through PCR, RT-PCR and quantitative PCR (qPCR) analysis. The transgenic plants were artificially challenged with viruses under confined glasshouse conditions and the load of virus particles were confirmed using DAC-ELISA, RT-PCR and histopathology in both transgenic and wild-type (WT) plants. The marker-free transgenic groundnut plants carrying TSV-CP+PBNV-NC genes witnessed delayed and less intense symptoms after viral inoculation, suggesting underlying resistance via a coat protein/nucleocapsid-mediated mechanism and indicated partial/non-durable resistance to TSV and PBNV. The marker free Agrobacterium-mediated transformation technique can be successfully used to generate transgenic peanuts having resistance to both Ilarvirus and Tospoviruses.This strategy may be applied to commercially important crops that are affected by Ilarvirus and Tospoviruses.