Sensitivity of Magnaporthe grisea to the Sterol Demethylation Inhibitor Fungicide Propiconazole

Abstract

Baseline sensitivity of Magnaporthe grisea to a sterol demethylation inhibitor (DMI) propiconazole was determined using 52 wild-type single-spore isolates. The 50% effective concentrations of these 52 isolates to propiconazole ranged from 0.145 to 1.446 lg ⁄ ml. Among the 52 isolates, two (07-82 and 04-006) were hypersensitive to propiconazole. The propiconazolehypersensitive (PHS) isolates were also hypersensitive to another DMI fungicide triadimefon, but not to a benzimidazole fungicide carbendazim. Compared with the propiconazole-sensitive (PS) isolates, the PHS isolates retained normal pathogenicity. Real-time PCR analysis showed that expression of cyp51 gene in the PHS isolates was not significantly different from that in the PS isolates. Analysis of DNA sequence of cyp51 gene showed that the PHS isolates 07-82 and 04-006 had an amino acid substitution at the codon position 234 and 450, respectively, where the amino acids were conserved in the CYP51 of other fungi, which indicated that the substitutions in CYP51 might be related to hypersensitivity of M. grisea to DMI fungicides.

Widespread distribution of resistance to triazole fungicides in Brazilian populations of the wheat blast pathogen

“…These fungicide concentrations were selected based on a preliminary experiment that established a dose-response curve using 16 isolates of PoTl and 12 doses of each fungicide. Because we could not find a sensitive strain within the PoTl populations, we included seven rice blast strains (PoOl), which belong to the same phylogenetic species as PoTl, have very similar CYP51A and CYP51B target genes, have no apparent differences in baseline sensitivity to DMIs, and were found to be highly sensitive to azoles (Fang et al, 2009;Pak et al, 2016;Ceresini et al, 2018;Dorigan et al, 2019 ( Figure S2). PCR was performed with Phusion High-Fidelity DNA polymerase (New England Biolabs), according to the manufacturer's instructions, with an annealing temperature of 70°C and an extension time of 60 s. Products were purified using the Wizard SV Gel and PCR Clean-Up System (Promega), then Sanger-sequenced by Eurofins Genomics (Germany) using sequencing primers CYP51B_912F, CYP51B_2704R, and CYP51B_1556F ( Figure S2).…”

In Vitro and Ex Vivo Antifungal Activities of Metconazole against the Rice Blast Fungus Pyricularia oryzae

“…DMI fungicides are the largest group of antifungal compounds that are widely used in modern agriculture and have been utilized in the control of plant diseases caused by Ascomycetes , Basidiomycetes and Fungi imperfecti. Epoxiconazole and propiconazole, belonging to the DMI fungicide group, have been reported to effectively control rice blast [ 36 , 37 , 38 ]. Metconazole is a DMI fungicide, and previous studies have shown that this fungicide has strong inhibitory effects on the mycelial growth of F. graminearum and F. pseudograminearum [ 30 , 39 , 40 ].…”

Low Availability of Efficient Fungicides for Rice Blast Control in Lowland Rice Cultivation in Brazil

“…Chen et al (2015) analyzed the effect of azoxystrobin and kresoxim-methyl fungicides for blast control in irrigated rice in China and found that both fungicides had disease control superior to 73% of efficiency and resulted in high grain yield, these results are in contrast of our results. Others reports showed that fungicide azoxystrobin is efficient in the rice blast control with direct reflection on grain yield in countries such as Italy, Taiwan, and the United States (Chen et al, 2015;Kunova et al, 2014;Kunova et al, 2012;Jin et al, 2009;Fang et al, 2009).…”