Skip to main content
ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Emerging Pests and Pathogens Research » Research » Publications at this Location » Publication #307792
Title: Evidence of a monogenic nature of the Nz Gene conferring resistance against Potato virus Y Strain Z (PVYZ) in potato

Author
item CHIKH-ALI, MOHAMAD - University Of Idaho
item ROWLEY, JENNY - University Of Idaho
item KUHL, JOSEPH - University Of Idaho
item Gray, Stewart
item KARASEV, ALEX - University Of Idaho

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2014
Publication Date: 6/6/2014
Citation: Chikh-Ali, M., Rowley, J., Kuhl, J., Gray, S.M., Karasev, A. 2014. Evidence of a monogenic nature of the Nz Gene conferring resistance against Potato virus Y Strain Z (PVYZ) in potato. American Journal of Potato Research. DOI: 10.1007/s12230-014-9395-7.

Interpretive Summary: Potato virus Y has become the number one disease issue for the U.S. seed potato industry and has the potential to become a major quality disease for the entire potato industry. Tuber necrotic strains of PVY have emerged over the past decade and have rapidly spread throughout all production areas due to a lack of control options. Here we report on the resistance gene in potato that is effective against a large proportion of the new tuber necrotic strains of PVY. This gene regulates a defense response in potato plants that are infected with these strains of PVY and that reduces the ability of the virus to spread in the plants. Therefore the virus is more difficult for aphid vectors to acquire virus from these plants and spread it to other plants. This resistance gene also reduces the spread of virus into tubers developing on the infected plant. The gene appears to be present in several potato varieties grown in the United States and therefore it may be easily transferred to new varieties using conventional plant breeding techniques. The resistance gene if widely deployed in potato varieties could offer an effective strategy to manage the tuber necrotic strains of PVY and minimize further spread of the virus.

Technical Abstract: Hypersensitive resistance (HR) to Potato virus Y (PVY) in potato (Solanum tuberosum) is conferred by strain-specific N genes. Two such genes have been identified in potato so far, Nytbr conferring HR to PVYo, and Nctbr conferring HR to PVYc. A third, putative gene Nztbr was proposed to confer HR against a distinct strain PVYz. However, due to the scarcity of the PVYz isolates of PVY, no formal proof of the monogenic nature of this new gene, Nztbr, was available until now. Here, we report on a genetic study of the Nztbr inheritance in three crosses between cultivars Maris Bard (Ny:Nz) and King Edward (ny:nz), and Maris Bard (Ny:Nz) and Russet Norkotah (ny:nz). A fully-sequenced PVYz isolate, L26, was used to screen the parents and progeny for a virus-induced HR phenotype in foliage. Based on the phenotypic analysis of 203 progeny, segregation of HR phenotype in the PVYz-infected plants was found to be 1:1, indicating a monogenic, dominant nature of the Nztbr gene. Since the PVYz strain includes PVY-NTN isolates associated with tuber necrotic ringspot disease (PTNRD) in susceptible potato cultivars, the Nztbr gene represents a valuable source of HR against PTNRD-inducing PVY isolates. This is the first demonstration that Nztbr is a single, dominant N gene in potato conferring resistance to the PVYz-NTN strain.