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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #220119
Title: Suppression of Resistance-breaking Beet Necrotic Yellow Vein Virus Isolates by Beet Oak-leaf Virus in Sugar Beet.

Author
item Liu, Hsing Yeh
item Lewellen, Robert

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2008
Publication Date: 7/20/2008
Citation: Liu, H., Lewellen, R.T. 2008. Suppression of Resistance-breaking Beet Necrotic Yellow Vein Virus Isolates by Beet Oak-leaf Virus in Sugar Beet.. Plant Disease 92:1043-1047

Interpretive Summary: Rhizomania is a serious disease of sugar beet. This disease is caused by Beet necrotic yellow vein virus (BNYVV) and vectored by the plasmodiophorid Polymyxa betae. Use resistant cultivars have been the only economical way to control this devastating disease. Partially resistant sugar beet cultivars based upon single dominant genes have been developed and are widely used by the sugar beet industry. Recently, resistance-breaking strains of Beet necrotic yellow vein virus (RB-BNYVV) were identified and characterized. When the occurrence of RB-BNYVV was surveyed throughout the sugar beet growing areas in the United States, most soil samples were shown to contain Beet oak-leaf virus (BOLV) as well. BNYVV and BOLV often occurred in the same area and sometimes in the same sugar beet plant. The possibility of interactions between these two Polymyxa betae transmitted sugar beet viruses was tested. Plants grown in soils infested with aviruliferous P. betae or carrying RB-BNYVV and BOLV, alone and in combination, were compared with plants grown in non-infested soil for differences in plant fresh weight and virus content as measured by enzyme-linked immunosorbent assay (ELISA). Rz1 and Rz2 resistance genes that condition resistance to BNYVV did not confer resistance to BOLV. BNYVV ELISA values were significantly higher in single infections than in mixed infections with BOLV, in both the rhizomania-resistant and -susceptible cultivars. In contrast, ELISA values of BOLV were not significantly different between single and mixed infections in both the rhizomania-resistant and -susceptible cultivars. Results indicate that BOLV may suppress BNYVV in mixed infections. Soils infested with P. betae significantly reduced fresh weight of sugar beet seedlings regardless of whether they were with or without one or both viruses or resistance genes.

Technical Abstract: Rhizomania, a very serious disease of sugar beet (Beta vulgaris L.), is caused by Beet necrotic yellow vein virus (BNYVV). Resistance allele Rz1 has been widely incorporated into commercial cultivars. Recently, resistance-breaking strains of Beet necrotic yellow vein virus (RB-BNYVV) were identified and characterized. When the occurrence of RB-BNYVV was surveyed throughout the sugar beet growing areas in the United States, most soil samples were shown to contain Beet oak-leaf virus (BOLV) as well. BNYVV and BOLV often occurred in the same area and sometimes in the same sugar beet plant. The possibility of interactions between these two Polymyxa betae transmitted sugar beet viruses was tested. Plants grown in soils infested with aviruliferous P. betae or carrying RB-BNYVV and BOLV, alone and in combination, were compared with plants grown in non-infested soil for differences in plant fresh weight and virus content as measured by enzyme-linked immunosorbent assay (ELISA). Rz1 and Rz2 resistance genes that condition resistance to BNYVV did not confer resistance to BOLV. BNYVV ELISA values were significantly higher in single infections than in mixed infections with BOLV, in both the rhizomania-resistant and -susceptible cultivars. In contrast, ELISA values of BOLV were not significantly different between single and mixed infections in both the rhizomania-resistant and -susceptible cultivars. Results indicate that BOLV may suppress BNYVV in mixed infections. Soils infested with P. betae significantly reduced fresh weight of sugar beet seedlings regardless of whether they were with or without one or both viruses or resistance genes.