Reduced sensitivity of azoxystrobin and thiophanate-methyl resistance in Lasiodiplodia theobromae from papaya.

Autor: Chen F; Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, China., Tsuji SS; Departamento de Agronomia, Universidade Federal Rural de Pernambuco, Recife, PE 52171, Brazil., Li Y; Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, China., Hu M; Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA., Bandeira MA; Departamento de Agronomia, Universidade Federal Rural de Pernambuco, Recife, PE 52171, Brazil., Câmara MPS; Departamento de Agronomia, Universidade Federal Rural de Pernambuco, Recife, PE 52171, Brazil., Michereff SJ; Centro de Ciências Agrárias e da Biodiversidade, Universidade Federal do Cariri, Crato, CE 63130, Brazil., Schnabel G; Plant & Environmental Sciences, Clemson University, Clemson, SC 29634, USA. Electronic address: schnabe@clemson.edu.
Jazyk: angličtina
Zdroj: Pesticide biochemistry and physiology [Pestic Biochem Physiol] 2020 Jan; Vol. 162, pp. 60-68. Date of Electronic Publication: 2019 Aug 31.
DOI: 10.1016/j.pestbp.2019.08.008
Abstrakt: Stem-end rot caused by Lasiodiplodia theobromae is one of the most devastating diseases of papaya in northeastern Brazil. It is most effectively controlled by applications of fungicides, including site-specific fungicides at risk for resistance development. This study investigated the molecular mechanisms of reduced sensitivity to the QoI fungicide azoxystrobin and resistance to the MBC fungicide thiophanate-methyl in L. theobromae from Brazilian orchards. The EC 50 values for azoxystrobin in sixty-four isolates ranged from 0.36 μg/ml to 364.24 μg/ml and the frequency distribution of EC 50 values formed a multimodal curve, indicating reduced sensitivity to azoxystrobin. In detached fruit assays reduced sensitive isolates were not controlled as effectively as sensitive isolates at lowest label rate. Partial fragments were obtained from target genes β-tubulin (751 bp) and Cytb (687 bp) of isolates resistant to thiophanate-methyl and reduced sensitivity to azoxystrobin. Sequence analysis of the β-tubulin fragment revealed a mutation corresponding to E198K in all thiophanate-methyl-resistant isolates, while reduced sensitivity to axoxystrobin was not attributable to Cytb gene alterations. The target gene-based mechanism conferring resistance to thiophanate-methyl will likely be stable even if selection pressure subsides. However, the mechanism conferring reduced sensitivity to azoxystrobin is not based on target gene modifications and thus may not be as stable as other genotypes with mutations in Cytb gene.
(Copyright © 2019 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: