Mutation in cyp51b and overexpression of cyp51a and cyp51b confer multiple resistant to DMIs fungicide prochloraz in Fusarium fujikuroi

Abstract

BACKGROUND Fusarium fujikuroi is a plant pathogen that causes rice bakanae disease. Prochloraz is an imidazole‐class sterol, 14α‐demethylase inhibitor (DMI), which has been in use for several years as a foliar spray to control Fusarium spp. on agriculturally important monocot crops. F. fujikuroi is highly resistant to prochloraz treatment, and the aim of this study was to clarify the mechanism by which F. fujikuroi renders itself resistant to prochloraz. RESULTS Recently, prochloraz‐resistant strains were identified over a vast geographical area in the agricultural regions of Zhejiang Province, China. It was found that 21.13% and 3.96% of the strains examined were highly resistant (HR) to prochloraz during 2017 to 2018. The HR strains contained a point mutation (S312T) in the FfCYP51B protein, while the strains identified with prochloraz susceptibility had no such point mutation in FfCYP51A/B/C. To confirm whether the mutations in FfCYP51B confer resistance to prochloraz, we exchanged the CYP51B locus between the sensitive strain and the resistant strain by homologous double exchange. The transformed mutants with a copy of the resistant fragment exhibited resistance to prochloraz, and the transformed mutants with a copy of the sensitive fragment exhibited sensitivity to prochloraz. Furthermore, qRT‐PCR analysis of Ffcyp51a/b/c gene expression revealed that Ffcyp51a and Ffcyp51b were significantly up‐regulated in the prochloraz‐resistant strains relative to the sensitive strains in F. fujikuroi. Contrary to our expectation, docking of prochloraz into the modeled binding pocket of FfCYP51B indicated that the affinity between prochloraz and the FfCYP51B increased after the amino acid at codon 312 changed to Thr. CONCLUSION The point mutation S312T in FfCYP51B and overexpression of Ffcyp51a and Ffcyp51b together lead to the prochloraz‐resistant phenotype in F. fujikuroi.

Assessment of Commercial Fungicides against Onion (Allium cepa) Basal Rot Disease Caused by Fusarium oxysporum f. sp. cepae and Fusarium acutatum

“…Such cases become more and more widespread [14]. Indeed, Prochloraz-responsive genes facilitating DMI-resistance have already been reported in other phytopathogens (see, for example [15,16]. One solution to cope with this problem is the use of a mixture of fungicides, each of which has a different action mechanism (see, for example [17,18]).…”

Tebuconazole resistance of Fusarium graminearum field populations from wheat in Henan Province

“…Also, the amino acid site mutation of CYP51A (Y459S/D/N, Y461S/H, I381V) and CYP51B (I381V) in M. graminicola resulted in moderate resistance against DMI fungicides (Leroux et al., 2007). The amino acid mutation of the CYP51B gene (S312T) and overexpression of FfCYP51A and FfCYP51B resulted in the resistance to DMI fungicides in F. fujikuroi (Zhang et al., 2021). A point mutation (Y136F) at the 136th amino acid of CYP51 protein in Erysiphe graminis resulted in resistance of E. graminis to DMI fungicides (Yan et al., 2009).…”

Various Methods for Controlling the <i>Bakanae</i> Disease in Rice

“…This enzyme is required for biosynthesis of ergosterol, a component of the fungal cell membrane that is essential for fungal growth. F. fujikuroi has three CYP51 genes (CYP51A, B, and C) [44]. DMIs include chemical classes such as imidazole, piperazine, pyridine, pyrimidine, and triazole.…”

“…Furthermore, in case of another Korean strain CF337, structure changes in the fungal cell wall and an ATP binding cassette (ABC) transporter were reported to confer prochloraz resistance [55]. Whereas, Zhang et al [44] reported that the S312T mutation in CYP51B and overexpression of the CYP51A/CYP51B genes caused prochloraz resistance in Chinese F. fujikuroi. Choi et al [56] found an association between survival factor 1 and F-box/WD-repeat protein with prochloraz sensitivity of F. fujikuroi.…”