Improved Identification and Detection of Select Agent Ralstonia solanacearum Strains Threatening the US Potato Industry

Phytobiomes Alliance project

Funded by

USDA Animal Plant Health Inspection Service (APHIS)


12 months


1 July 2022 - 31 June 2023 - extended to 31 December 2023


Kellye Eversole, Eversole Associates

Project Overview

The goal of this project is to develop a data-driven framework for improving the regulation and detection of Rs strains that threaten US agriculture.

The primary purpose of this project is to precisely circumscribe the authentically threatening Rs strains that are highly aggressive on potato at cool temperatures using a combination of phenotypic assays and bioinformatics to evaluate current diagnostic markers. If current markers accurately identify the authentically threatening strains, new diagnostic markers will be developed that can be used to provide an affirmative positive test result for a strain that is not a Select Agent based on a negative test with current markers. If current markers are found to give false positives or false negatives, new diagnostic markers will be developed.


Objective 1: Use three validated and quantitative bioassays to determine if aggressive potato brown rot virulence at cool temperatures is a shared and unique property of strains identified by genome-based classification as PL isolates.

Objective 2: Identify genomic sequences unique to Rs strains that authentically threaten US potato production, evaluate current diagnostics markers based on these results, and develop additional markers to minimize the risk of false positives and negatives.