Survival of Xanthomonas fragariae on common materials

Authors: Turechek, William; WINTERBOTTOM, CHIRSTOPHER - Goodfarms, Llc; MEYER-JERTBERG, MELODY - Driscoll'S; WANG, H - Clemson University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2022
Publication Date: 5/31/2022
Citation: Turechek, W., Winterbottom, C., Meyer-Jertberg, M., Wang, H. 2022. Survival of Xanthomonas fragariae on common materials. Plant Disease. 106 (in press). https://doi.org/10.1094/PDIS-03-22-0719-RE.
DOI: https://doi.org/10.1094/PDIS-03-22-0719-RE

Interpretive Summary: Xanthomonas fragariae causes strawberry angular leaf spot (ALS), an important disease to the strawberry nursery production industry in North America. To identify potential inoculum sources for strawberry angular leaf spot, the survival of X. fragariae was examined on the surfaces of eleven common materials found in strawberry nurseries in a designed experiment: corrugated cardboard, cotton balls, cotton cloth (t-shirt), strawberry leaf, sheet metal, plastic, rubber, Tyvek, wood (balsa), glass (microscope slide), and latex (latex glove). The bacteria were artificially inoculated on to each material, maintained at ~20°C (room temperature) or -4°C (the cold storage temperature for dormant plants in strawberry nurseries), and then recovered from each of the eleven surfaces at 1, 3, 7, 14, 30, 60, 90, 180, 270 and 365 days after inoculation (DAI) to determine survival. Results showed that all materials were capable of harboring viable bacteria up to 7 DAI when stored at -4°C and that the longest survival was 270 DAI observed on cardboard stored at -4°C. At room temperature, cardboard, cotton balls, cotton t-shirt, and strawberry leaf tissue supported bacteria up to 14 DAI. The information provided by this study can be used to improve sanitation practices for angular leaf spot management in strawberry nurseries.

Technical Abstract: Xanthomonas fragariae causes strawberry angular leaf spot (ALS), an important disease to the strawberry nursery production industry in North America. To identify potential inoculum sources for strawberry angular leaf spot, the survival of X. fragariae was examined on the surfaces of eleven common materials found in strawberry nurseries in a designed experiment: corrugated cardboard, cotton balls, cotton cloth (t-shirt), strawberry leaf, sheet metal, plastic, rubber, Tyvek, wood (balsa), glass (microscope slide), and latex (latex glove). The bacteria were artificially inoculated on to each material, maintained at ~20°C (room temperature) or -4°C (the cold storage temperature for dormant plants in strawberry nurseries), and then recovered from each of the eleven surfaces with PBS-soaked cotton balls at 1, 3, 7, 14, 30, 60, 90, 180, 270 and 365 days after inoculation (DAI). Survival rate was determined with a viability qPCR procedure and in a plant bioassay that involved rub inoculation of strawberry leaflets with the cotton balls. Results showed that X. fragariae could survive on all surfaces, but survival time differed among materials and storage temperature. All materials were capable of harboring viable bacteria up to 7 DAI when stored at -4°C based on resulting lesions from recovered bacteria in the plant bioassay. The longest survival and highest disease transmission rate was 270 DAI observed on cardboard stored at -4°C. At room temperature, cardboard, cotton balls, cotton t-shirt, and strawberry leaf tissue supported small bacterial populations up to 14 DAI. The information provided by this study can be used to improve sanitation practices for angular leaf spot management in strawberry nurseries.