High Quinone Outside Inhibitor (QoI) Resistance Risk in Colletotrichum Species Causing Strawberry Crown Rot in Korea
Year: 2024
Type: article
Abstract: Anthracnose crown rot caused by Colletotrichum spp. is one of the most important diseases of strawberry (Fragaria × ananassa) in Korea. Single spore isolates of 72 Colletotrichum species collected in 2018, 2020, and 2023 from different locations in Chungbuk, Chungnam, Gyeongbuk, Gyeongnam, and Jeolla regions were characterized using a multi-locus sequence typing (MLST) of four genetic loci (GAPDH, ACT, TUB2, and ITS). Isolates were identified as C. fructicola (n=64) and C. siamense (n=8). Quinone outside inhibitors (QoIs) active ingredient pyraclostrobin is utilized to manage anthracnose crown rot in the field. Sensitivity to pyraclostrobin were assessed on potato dextrose agar using a mycelial growth inhibition assay at 20, 4, 0.8, 0.16, and 0.032 μg/ml fungicide concentrations. Our results demonstrated that all the 72 Colletotrichum spp. isolates were not inhibited by pyraclostrobin at all the tested fungicide concentrations, with EC50 ranging between 13 and >100 μg/ml. Sequences of the partial cytochrome b (cyt b) gene flanking the mutation site revealed the presence of the G143A mutation in all the isolates. No other site modifications were detected in the cyt b gene. Cross resistance assays with 10 selected isolates involving EC50 values of pyraclostrobin, mandestrobin, trifloxystrobin, and kresoxim-methyl showed positive correlations among these fungicides. These findings suggest a high risk of resistance development associated with using QoI fungicides to control the anthracnose crown rot of strawberries in Korea.
Source: Research in Plant Disease
Institution: Chungbuk National University
Language: English
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $700
Funder: Rural Development Administration
Award: G4883841522
OpenAlex ID: W4405900921