A world‐wide analysis of reduced sensitivity to DMI fungicides in the banana pathogen Pseudocercospora fijiensis

Abstract

BACKGROUND: Pseudocercospora fijiensis is the causal agent of the black leaf streak disease (BLSD) of banana. Bananas are important global export commodities and a major staple food. Their susceptibility to BLSD pushes disease management towards excessive fungicide use, largely relying on multisite inhibitors and sterol demethylation inhibitors (DMIs). These fungicides are ubiquitous in plant disease control, targeting the CYP51 enzyme. We examined sensitivity to DMIs in P. fijiensis field isolates collected from various major banana production zones in Colombia, Costa Rica, Dominican Republic, Ecuador, the Philippines, Guadalupe, Martinique and Cameroon and determined the underlying genetic reasons for the observed phenotypes. RESULTS:We observed a continuous range of sensitivity towards the DMI fungicides difenoconazole, epoxiconazole and propiconazole with clear cross-sensitivity. Sequence analyses of PfCYP51 in 266 isolates showed 28 independent amino acid substitutions, nine of which correlated with reduced sensitivity to DMIs. In addition to the mutations, we observed up to six

Probiotic Endophytes for More Sustainable Banana Production

“…An extensive application of chemical fungicides was used as a first option to combat this disease. However, this strategy quickly became ineffective due to the emergence of resistant and tolerant P. fijiensis populations to the chemical agents (e.g., carbendazim, azoxystrobin, propiconazole and mancozeb) [ 5 , 112 ]. Another strategy involved removing the leaves with lesions weekly (at the first streak stage) to reduce the amount of inoculum (ascospores).…”

Genetic Characteristics and Metabolic Interactions between Pseudocercospora fijiensis and Banana: Progress toward Controlling Black Sigatoka

“…Chemical control is achieved via a combination of site-specific and protectant/multi-site fungicides. Eight main site-specific classes of fungicides with different modes of action are commonly used in mixtures or alternating patterns: QoIs (quinone outside inhibitors), DMIs (demethylation inhibitors), SDHIs (succinate dehydrogenase inhibitors), BCMs (benzimidazoles), N-phenylcarbamates, anilinopyrimidines, amines, and guanidines [ 23 ], with DMIs the most widely used [ 24 ]. Medium to high levels of resistance have been reported in many countries for BCMs, DMIs, and QoIs, and resistance has been reported for SDHIs [ 9 , 11 , 23 , 24 , 25 ].…”

“…Eight main site-specific classes of fungicides with different modes of action are commonly used in mixtures or alternating patterns: QoIs (quinone outside inhibitors), DMIs (demethylation inhibitors), SDHIs (succinate dehydrogenase inhibitors), BCMs (benzimidazoles), N-phenylcarbamates, anilinopyrimidines, amines, and guanidines [ 23 ], with DMIs the most widely used [ 24 ]. Medium to high levels of resistance have been reported in many countries for BCMs, DMIs, and QoIs, and resistance has been reported for SDHIs [ 9 , 11 , 23 , 24 , 25 ]. A recent study of resistance to DMIs in P. fijiensis from eight countries in South and Central America, the Caribbean, Africa, and south-east Asia identified a diversity in resistance responses to three DMI fungicides and defined the genetic basis of resistance as mutations in a gene for a cytochrome P450 enzyme (CYP51) [ 24 ].…”

“…Medium to high levels of resistance have been reported in many countries for BCMs, DMIs, and QoIs, and resistance has been reported for SDHIs [ 9 , 11 , 23 , 24 , 25 ]. A recent study of resistance to DMIs in P. fijiensis from eight countries in South and Central America, the Caribbean, Africa, and south-east Asia identified a diversity in resistance responses to three DMI fungicides and defined the genetic basis of resistance as mutations in a gene for a cytochrome P450 enzyme (CYP51) [ 24 ]. Multi-site fungicides used for black Sigatoka control include mancozeb, chlorothalonil, metiram, captan, thiram, and propineb; these are considered fungicides of low resistance risk [ 23 ].…”

Detection of fungicide resistance to fludioxonil and tebuconazole in Fusarium pseudograminearum, the causal agent of Fusarium crown rot in wheat

“…Resistance to fludioxonil has been reported in a broad range of plant pathogenic fungi such as Colletotrichum gloeosporioides from fruit ( Schnabel et al, 2021 ), Sclerotinia sclerotiorum from oilseed rape ( Kuang et al, 2011 ), Botrytis cinerea from apple and strawberry ( Zhao et al, 2010 ; Fernández-Ortuño et al, 2016 ). A range of DMI-resistant fungal strains have been reported from pathogenic populations of Botrytis cinerea ( Zhang et al, 2020 ), Pseudocercospora fijiensis ( Chong et al, 2021 ), F. graminearum ( de Chaves et al, 2022 ), Monilinia fructicola ( Lesniak et al, 2020 ), and Venturia nashicola ( Ishii et al, 2021 ).…”