- Agronomic: potatoes
- Crop Production: crop improvement and selection, plant breeding and genetics
- Education and Training: extension, networking
- Pest Management: genetic resistance
Potato Virus Y: Testing New Potential Resistance Genes to an Enduring Threat to Potato Production
Potato Virus Y (PVY) is a major problem facing the Pacific Northwest potato industry. PVY infection in growers’ fields can lead to severe yield penalty and unmarketable tubers, which translate into significant economic losses. Spraying insecticides to control aphids, the primary vectors of PVY, or applying mineral oils to inhibit viral transmission have limited effectiveness due to the non-persistent nature of aphid transmission of PVY. A sustainable environmentally friendly solution to control PVY is the planting of potato varieties that are resistant to PVY. Many varieties grown in the western US are resistant to the ordinary strain of PVY. However, new recombinant strains that have become predominant in growers’ fields have defeated this strain-specific resistance. One major constraint to develop effective, long-term resistance against PVY is our lack of understanding of the strain-specific resistance mechanism used by some potato varieties to fight off PVY. This lack of knowledge also hinders our ability to understand how new PVY strains have broken existing resistance. Therefore, this project aims to shed light on the PVY-resistance mechanism and its breaking. Specifically, we propose to characterize the function of two genes that we hypothesize are crucial in the resistance response to PVY. This project has two objectives: (1) to evaluate the effect of disabling the targeted genes on the resistance to PVY, and (2) to analyze changes in gene expression in plants whose genes are disabled to identify network of genes involved in the resistance to PVY. Data from this project will help to better predict resistance failure and implement effective, sustainable anti-PVY strategies. Results from this project will be published in scientific journals and disseminated to stakeholders through extension publications and presentations at local extension events.
Through transcriptomics analyses, we have identified two candidate genes that we hypothesize are crucial in mounting the resistance response against PVY (Goyer et al 2015). In this project, we propose to determine the role of these genes, called PIP and MYC hereafter, in the resistance response and assess their potential use as resistance genes.
Objective #1: Evaluate the resistance response of potatoes whose PIP and MYC genes are disabled to three different PVY strains
Sub-objective #1: Evaluation of resistance during current season inoculation
The aim of this sub-objective is to determine resistance/susceptibility of plants whose PIP or MYC genes are disabled (i.e. knocked out) to inoculation with either of three PVY strains (N-Wilga, NTN, O) by monitoring leaf and tuber symptoms and by assessing the virus spread by PCR. The background variety of potato used to produce the disabled lines, Premier Russet, is resistant to PVYO but susceptible to other strains. Changes in the resistance response in the knockout lines compared to controls will provide evidence that these genes play some role in the establishment of the resistance response. This work should take about three months.
Sub-objective #2: Evaluation of resistance during secondary infection
The aim of this sub-objective is to assess resistance/susceptibility to seed-borne secondary infection of the virus. Tubers harvested in sub-objective #1 will be planted in pots and virus infection will be evaluated in foliage and tuber progeny. This work should take about three months.
Objective #2: Analyze changes in the overall gene expression in plants whose genes are disabled
The aim of this objective is to identify network of genes involved in the resistance response to PVY. For this, we will compare the foliage transcriptome of knockout and control lines in both PVY-inoculated and non-inoculated plants. This work should take about two months.