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A new mechanism for reduced sensitivity to demethylation-inhibitor fungicides in the fungal banana black Sigatoka pathogen Pseudocercospora fijiensis
- Source :
- Molecular Plant Pathology. 19:1491-1503
- Publication Year :
- 2018
- Publisher :
- Wiley, 2018.
-
Abstract
- The Dothideomycete Pseudocercospora fijiensis, previously Mycosphaerella fijiensis, is the causal agent of black Sigatoka, one of the most destructive diseases of bananas and plantains. Disease management depends on fungicide applications, with a major contribution from sterol demethylation-inhibitors (DMIs). The continued use of DMIs places considerable selection pressure on natural P. fijiensis populations, enabling the selection of novel genotypes with reduced sensitivity. The hitherto explanatory mechanism for this reduced sensitivity was the presence of non-synonymous point mutations in the target gene Pfcyp51, encoding the sterol 14α-demethylase enzyme. Here, we demonstrate a second mechanism involved in DMI sensitivity of P. fijiensis. We identified a 19-bp element in the wild-type (wt) Pfcyp51 promoter that concatenates in strains with reduced DMI sensitivity. A polymerase chain reaction (PCR) assay identified up to six Pfcyp51 promoter repeats in four field populations of P. fijiensis in Costa Rica. We used transformation experiments to swap the wt promoter of a sensitive field isolate with a promoter from a strain with reduced DMI sensitivity that comprised multiple insertions. Comparative in vivo phenotyping showed a functional and proportional up-regulation of Pfcyp51, which consequently decreased DMI sensitivity. Our data demonstrate that point mutations in the Pfcyp51 coding domain, as well as promoter inserts, contribute to the reduced DMI sensitivity of P. fijiensis. These results provide new insights into the importance of the appropriate use of DMIs and the need for the discovery of new molecules for black Sigatoka management.
- Subjects :
- 0106 biological sciences
0301 basic medicine
Genetics
Black sigatoka
Point mutation
Soil Science
Plant Science
Biology
biology.organism_classification
01 natural sciences
law.invention
Fungicide
03 medical and health sciences
Transformation (genetics)
030104 developmental biology
law
Botany
Genotype
Mycosphaerella
Agronomy and Crop Science
Molecular Biology
Pathogen
Polymerase chain reaction
010606 plant biology & botany
Subjects
Details
- ISSN :
- 14646722
- Volume :
- 19
- Database :
- OpenAIRE
- Journal :
- Molecular Plant Pathology
- Accession number :
- edsair.doi...........14d95cc83e808004d81e22e9db2c1175