Occurrence of fenhexamid resistance in <i>Botrytis cinerea</i> from greenhouse strawberries in China

Zhou, Feng; Lü, Fan; Zhang, Can; Qi, Hexing; Wang, Xiaodong; Zhang, Guozhen

doi:10.1111/jph.12580

Cited by 12 publications

(1 citation statement)

References 29 publications

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“…The mycelial growth assay described in a previous study [33] was used to determine the effect of tebuconazole treatment on F. graminearum. Briefly, each isolate was initially established on PDA by inoculation from the glycerol stock, and culture at 25°C for 3 days.…”

Section: Mycelial Growth Assaymentioning

confidence: 99%

Baseline tebuconazole sensitivity and potential resistant mechanisms in Fusarium graminearum

Zhou,

jiao

et al. 2024

Preprint

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Background The Fusarium head blight caused by Fusarium graminearum results in reduced crop yields and the potential for vomitoxin contamination, which poses a risk to both human and livestock health. The primary method of control relies on the application of chemical fungicides. Results The current study found that the tebuconazole sensitivity of 165 F. graminearum isolates collected from the Huang-Huai-Hai region of China between 2019 and 2023 ranged from 0.005 to 2.029 µg/mL, with an average EC50 value of 0.33 ± 0.03 µg/mL. The frequency distribution conformed to a unimodal curve around the mean, and therefore provides a useful reference for monitoring the emergence of tebuconazole resistance in field populations of F. graminearum. Analysis of five tebuconazole-resistant mutants produced under laboratory conditions indicated that although the mycelial growth of the mutants were significantly (p < 0.05) reduced, spore production and germination rates could be significantly (p < 0.05) increased. However, pathogenicity tests confirmed a severe fitness cost associated with tebuconazole resistance, as all of the mutants completely loss the ability to infect host tissue. Furthermore, in general the resistant mutants were found to have increased sensitivity to abiotic stress, such as ionic and osmotic stress, though not to Congo red and oxidative stress, to which they were more tolerant. No cross-resistance was detected between tebuconazole and other unrelated fungicides such as flutriafol, propiconazole and fluazinam, but there was a clear negative cross-resistance with triazole fungicides including fludioxonil, epoxiconazole, metconazole, and hexaconazole. Meanwhile, molecular analysis identified several point mutations in the CYP51 genes of the mutants, which resulted in two substitutions (I281T, and T314A) in the predicted sequence of the FgCYP51A subunit, as well as seven (S195F, Q332V, V333L, L334G, M399T, E507G, and E267G) in the FgCYP51C subunit. In addition, it was also noted that the expression of the CYP51 genes in one of the mutants, which lacked point mutations, was significantly up-regulated in response to tebuconazole treatment. Conclusions These results provide useful data that allow for more rational use of tebuconazole in the control of F. graminearum, as well as for more effective monitoring of fungicide resistance in the field.

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Section: Mycelial Growth Assaymentioning

confidence: 99%