Believing is seeing: lessons from emerging viruses in grapevine

Abstract

Among the grapevine viruses recently identified, grapevine vein clearing virus (GVCV), grapevine Pinot gris virus (GPGV) and grapevine red blotch virus (GRBV) have emerged in the last decade as new threats to the grape and wine industry. Initially reported in Italy (GPGV) and the USA (GVCV and GRBV), GPGV and GRBV have a wider distribution at present, likely as a result of an extensive exchange of infected, propagative material, while GVCV seems to remain restricted to the mid-western regions in the USA. Much progress has been made on the ecology of these three emerging viruses since the last reviews were published in 2017 (Cieniewicz et al. 2017a; Qiu and Schoelz 2017; Saldarelli et al. 2017). Here we compile and critically analyze the latest information on these three viruses with a special emphasis on the (i) association between the genetic make-up of GPGV isolates and chlorotic mottling and leaf deformation symptoms, (ii) epidemiological and ecological attributes of GVCV and GRBV, and (iii) impacts of GRBV, particularly on molecular underpinnings of fruit ripening physiological pathways. Common trends among these three emerging grapevine viruses but also some unique characteristics are highlighted. Finally, we conclude on how critical it is to embrace ‘believing is seeing’ in the case of emerging grapevine viruses to remain relevant and impactful in providing research-based management solutions, while leading a sustained dialogue with grape grower’s communities, extension educators, policy makers and regulatory authorities.