Location: Temperate Tree Fruit and Vegetable Research
Project Number: 2092-21220-002-019-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Nov 15, 2017
End Date: Jun 30, 2019
Objective:
Tobacco rattle virus (TRV) is a serious tuber necrotic virus of potato that is of significant concern to growers in the United States. Tuber defects caused by TRV infection can result in tuber rejection at processing. The overall goal of this large, multiple-PI and multi-state project is to help growers reduce the risk of TRV (and other tuber necrotic viruses) at harvest. The portion of this project that Agricultural Research Service (ARS) in Prosser, Washington (WA) is responsible for is threefold. 1) Since the Pacific Northwest puts a large percent of harvested potatoes into cold storage, our goal is to assess symptom development and viral titer in tubers over time in storage. 2) Utilize the Washington State processing russet seed lot trials to survey the overall level of TRV present in potato seed. 3) Using a TRV-infected field, evaluate the resistant and susceptible parents of a segregating population for susceptibility to TRV. These objectives will aid in the overall understanding of TRV in-season in the Pacific Northwest, and help in the advancement of germplasm development for resistance to TRV.
Approach:
Potatoes will be grown in a TRV-infected stubby root nematode field at the Washington State University research farm in Prosser, WA. At harvest, potatoes will be sent to the University of Idaho laboratory in Kimberly, Idaho for proper cold storage. After harvest, tubers will be initially sampled by University of Idaho scientists for TRV symptom severity and effects on fry color, and an internal tuber sample will be collected and sent to our laboratory in Prosser, WA for molecular detection of TRV. Following nucleic acid extraction of each tuber sample, the samples will be subjected to reverse-transcription PCR for the detection of TRV. Molecular detection of TRV will be correlated to TRV symptom severity and tuber characteristics at frying. This process will be repeated on tubers from each variety held in cold storage for approximately five and nine months. Correlation in TRV symptoms and molecular detection will be made following all time points. In collaboration with a Washington State University research scientist, tubers will be sampled from a large potato seed lot trial conducted at the WSU farm in Othello, WA. The WSU scientist coordinates the seed lot trial in WSU and ensures that each lot is submitted for planting and subsequent grow-out. Tubers will be selected from Russet potato varieties submitted to the trial and taken to the ARS laboratory in Prosser, WA for processing. Tubers will be sliced for internal defects characteristic of TRV infection, and sample for nucleic acid extraction. Following extractions, TRV will be detected from each sample using reverse transcription PCR.
Using the TRV-infected stubby root nematode research plot at the Washington State University research farm in Prosser, WA, a segregating population showing from parents with either extreme resistance or with susceptibility to TRV will be planted and grown in randomized plot formation. At harvest, tubers will be scored visually for presence of TRV symptoms, and sampled for molecular detection of TRV in the lab. Here, nucleic acids will be extracted and reverse transcription PCR will be used to determine the presence of TRV. Molecular data will be correlated to the visual symptoms for the segregating population.
