Role of Viral Diagnostics in Quarantine for Plant Genetic Resources and Preparedness

Abstract

International exchange of plant genetic resources (PGR) and trade play an important role in the long-distance dissemination of destructive viruses/strains. The ICAR-NBPGR has been empowered for quarantine processing of imported PGR including transgenics meant for research purposes. Adopting a workable strategy of post-entry quarantine growing/inspection followed by use of combination of detection techniques viz., electron microscopy, ELISA and RT-PCR, 45 viruses of great economic and quarantine importance were intercepted in imported PGR in the last three decades (1985–2016). The interceptions include 19 viruses not yet reported from India viz., Barley stripe mosaic virus, Bean mild mosaic virus, Bean pod mottle virus, Broad bean mottle virus, Broad bean stain virus, Broad bean true mosaic virus, Cherry leaf roll virus, Cowpea mottle virus, Cowpea severe mosaic virus, Dioscorea latent virus, Garlic virus C, High plains virus, Maize chlorotic mottle virus, Pea enation mosaic virus, Peanut sunt virus, Pepino mosaic virus, Raspberry ringspot virus, Tomato ringspot virus and Wheat streak mosaic virus. Besides, 21 viruses not known to occur on particular host(s) in India were intercepted and 23 viruses were intercepted in germplasm imported from CGIAR centres. Fourteen viruses including nine viruses not reported from India have been intercepted in transgenic germplasm. Even though some of the intercepted viruses are not known to occur in India, their potential vectors exist and also congenial conditions to multiply, disseminate and spread destructive exotic viruses/strains. India also need to establish a strong network of interconnected accredited laboratories able to quickly diagnose new viruses/strains; enhance surveillance capacity and develop early warning systems. This makes it imperative that India should put in place a “National Plant Pests Diagnostic and Certification Network” to enhance preparedness.