Engineering transgenic rhizomania resistance

Abstract

The only practical means to ensure viability and profitability of the sugar beet crop is to provide efficient protection against rhizomania, caused by beet necrotic yellow vein virus (BNYVV), through the use of varieties, specifically bred as resistant to the disease. Although breeding ingenuity has to date achieved successful control of the disease throughout the world, resistant varieties may still suffer significant losses. At the same time, evolutionary changes in the pathogen continuously pose new challenges and require adjustments in relevant breeding programs if they were to keep providing a durable crop protection through the use of better resisting varieties. Given the fact that acquiring resistance from the repertoire of the crops’ gene pool is delimited by the scarcity of natural genetic sources of resistance to BNYVV, transgenesis offers the possibility to broaden the options for rhizomania resistance. Initial attempts to generate transgenic rhizomania resistance were based on the pathogen-derived resistance (PDR) concept. Recent understanding of the aspects underlying the antiviral pathways of RNA silencing however, has placed the focus of interest on generating rhizomania resistance based on the exploitation of the discovered innate defense mechanism. Alternative resistance strategies involved the employment of genes originating from nonviral sources. This chapter reviews the latest advances in breeding for rhizomania resistance in transgenic sugar beet plants. © 2016 Springer International Publishing Switzerland.