Pest Management Science (2018) 74, 607-616

Yi-Ping Hou, Xiang-Pu Qu, Xue-Wei Mao, Jing Kuang, Ya-Bing Duan, Xiu-shi Song, Jian-Xin Wang, Chang-Jun Chen and Ming-Guo Zhou (2018)
Resistance mechanism of Fusarium fujikuroi to phenamacril in the field
Pest Management Science 74 (3), 607-616
Abstract:
Background
Rice bakanae disease, mainly caused by Fusarium fujikuroi, is an important disease of rice. Phenamacril has been used to control the disease for a few years in China. In 2016, nine phenamacril-resistant strains were found in the field in Zhejiang Province. The aim of the study was to clarify the mechanism of resistance of F. fujikuroi to phenamacril and the fitness of resistant strains.
Results
The nine F. fujikuroi strains examined were highly resistant to phenamacril. Eight of them had the point mutation TCA (Ser) ^- CCA (Pro) at codon 219 in the Myosin-5 protein, while the other had the point mutation TCA (Ser) ^- TTA (Leu) at codon 219. Myosin-5 replacement between resistant and sensitive strains confirmed that the point mutation in Myosin-5 caused the resistance of F. fujikuroi to phenamacril. Docking of phenamacril into the modeled binding pocket of Myosin-5 showed that the affinity between phenamacril and Myosin-5 decreased and a hydrogen bond could not be formed between phenamacril and the amino acid at codon 219 after it changed to Pro or Leu. There was no cross-resistance between phenamacril and other fungicides. The eight resistant strains containing the point mutation S219P had almost the same fitness as the sensitive strains, while the one resistant strain containing the point mutation S219 L showed decreased mycelial growth, sporulation and pathogenicity.
Conclusion
In the field, the point mutation S219P or S219 L in Myosin-5 conferred high resistance to phenamacril in F. fujikuroi. The point mutation S219P did not affect the fitness of F. fujikuroi, while the point mutation S219 L decreased its fitness.
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Link to article at publishers website
Database assignments for author(s): Ming-Guo Zhou, Yabing Duan, Chang-Jun Chen, Yiping Hou, Jing Kuang

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Fusarium fujikuroi	Rice (Oryza)	China (south)