Shifting sensitivity of septoria tritici blotch compromises field performance and yield of main fungicides in Europe.

Septoria tritici blotch (STB; ) is a severe leaf disease on wheat in Northern Europe. Fungicide resistance in the populations of is increasingly challenging future control options. Twenty-five field trials were carried out in nine countries across Europe from 2019 to 2021 to investigate the efficacy of specific DMI and SDHI fungicides against STB.

Evidence for the association of target-site resistance in cyp51 with reduced DMI sensitivity in European Cercospora beticola field isolates.

Background: Cercospora leaf spot caused by Cercospora beticola is the most relevant foliar disease in sugar beet cultivation. In the last decade a decreasing sensitivity of C. beticola towards demethylation inhibitors (DMIs) occurred.

Sensitivity of the Population in Algeria to Quinone outside Inhibitors, Succinate Dehydrogenase Inhibitors and Demethylation Inhibitors.

Net blotch of barley caused by (Died.) Drechsler, is one of the most destructive diseases on barley in Algeria. It occurs in two forms: f.

Competitive Fitness of Phakopsora pachyrhizi Isolates with Mutations in the CYP51 and CYTB Genes.

Soybean rust (Phakopsora pachyrhizi) in Brazil is mainly controlled with applications of fungicides, including demethylation inhibitors (DMI) and quinone outside inhibitors (QoI). Isolates with less sensitivity to DMI and QoI have been reported, and these have been found to have mutations in the CYP51 and CYTB genes, respectively. There have been no reports of fitness costs in isolates with mutations in CYP51 and CYTB, and the aim of this work was to compare the competitive ability of isolates with lower DMI or QoI sensitivities with that of sensitive (wild-type) isolates.

Proposal for a unified nomenclature for target-site mutations associated with resistance to fungicides.

Evolved resistance to fungicides is a major problem limiting our ability to control agricultural, medical and veterinary pathogens and is frequently associated with substitutions in the amino acid sequence of the target protein. The convention for describing amino acid substitutions is to cite the wild-type amino acid, the codon number and the new amino acid, using the one-letter amino acid code. It has frequently been observed that orthologous amino acid mutations have been selected in different species by fungicides from the same mode of action class, but the amino acids have different numbers.

Emergence of succinate dehydrogenase inhibitor resistance of Pyrenophora teres in Europe.

Background: Net blotch caused by Pyrenophora teres is an important disease of barley worldwide. In addition to strobilurins (quinone ouside inhibitors) and azoles (demethylation inhibitors), succinate dehydrogenase inhibitors (SDHIs) are very effective fungicides for net blotch control. Recently, SDHI-resistant isolates have been found in the field.

Differences in the efficacy of carboxylic acid amide fungicides against less sensitive strains of Plasmopara viticola.

Background: Plasmopara viticola is controlled by fungicides with different modes of action, including carboxylic acid amides (CAAs). The aim of this study was to evaluate differences in the response of CAA-resistant P. viticola strains towards CAAs.

Detection of the F129L mutation in the cytochrome b gene in Phakopsora pachyrhizi.

Background: Asian soybean rust, caused by Phakopsora pachyrhizi, is mostly controlled by demethylation inhibitor (DMI) and quinone outside inhibitor (QoI) fungicides. Mutations in the cytochrome b (CYTB) gene can lead to pathogen resistance to QoIs. The occurrence of the mutations in codons 129, 137 and 143 in the CYTB gene was investigated, and a pyrosequencing assay was developed for rapid and quantitative detection of the F129L mutation.

A Botrytis cinerea Population from a Single Strawberry Field in Germany has a Complex Fungicide Resistance Pattern.

Gray mold, caused by the fungus Botrytis cinerea, is one of the most important diseases of strawberry in Germany. The application of site-specific fungicides remains the main strategy to reduce disease incidence and severity in the field. Isolates (n = 199) were collected from fungicide-treated strawberry fruit at a German research site with a long history of fungicide efficacy trials against gray mold.

Binding of the respiratory chain inhibitor ametoctradin to the mitochondrial bc1 complex.

Background: Ametoctradin is an agricultural fungicide that inhibits the mitochondrial bc1 complex of oomycetes. The bc1 complex has two quinone binding sites that can be addressed by inhibitors. Depending on their binding sites and binding modes, the inhibitors show different degrees of cross-resistance that need to be considered when designing spray programmes for agricultural fungicides.

Sensitivity of Phakopsora pachyrhizi towards quinone-outside-inhibitors and demethylation-inhibitors, and corresponding resistance mechanisms.

Background: Since the invasion of Phakopsora pachyrhizi (Syd. & P. Syd.

A Two-Step Molecular Detection Method for Pyrenophora tritici-repentis Isolates Insensitive to QoI Fungicides.

Tan spot, caused by Pyrenophora tritici-repentis, is an important disease of wheat worldwide. To manage tan spot, quinone outside inhibitor (QoI) fungicides such as azoxystrobin and pyraclostrobin have been applied in many countries. QoI fungicides target the cytochrome b (cyt b) site in complex III of mitochondria and, thus, pose a serious risk for resistance development.

Generation and characterization of isolates of Peronophythora litchii resistant to carboxylic acid amide fungicides.

Four isolates of Peronophythora litchii with resistance to carboxylic acid amide (CAA) fungicides were selected on fungicide-amended agar. These isolates had various levels of resistance, as evidenced by their resistance factor (RF), which is the 50% effective concentration (EC(50)) value of a particular isolate divided by that of the wild-type parent. RF values to dimethomorph for the four isolates were 15, 24, 141, and >1,500.

Modulation of multidrug resistance in human ovarian cancer cell lines by inhibition of P-glycoprotein 170 and PKC isoenzymes with antisense oligonucleotides.

Multidrug resistance in human ovarian carcinoma cell lines is caused by the expression of several related proteins, namely P-glycoprotein 170 (Pgp-170), glutathione S-transferase-pi GST-pi), and thymidylate synthase (TS). These proteins seem to be regulated by a common mechanism in which the expression of protein kinase C (PKC) is involved. Additionally, the function of Pgp-170 is dependent on PKC phosphorylation.