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Adaptation of Pyrenophora tritici-repentis to fungicides. Different isolates (Fig. 4A; I, II and III) were allowed to adapt to different concentrations (Fig. 4A; 1, 5 and 10 ppm) of a strobilurin fungicide and plated out on agar plates containing 50 ppm of the same fungicide. Non-adapted control isolates (Fig. 4A; 0) were unable to grow. Isolates adapted to three different strobilurin fungicides (Fig. 4B; positions b, c and d) and an isolate adapted to an azole fungicide (Fig. 4B; position e) were able to grow on a plate containing 50 ppm of a strobilurin fungicide. A non-adapted control isolate (Fig. 4B; position a) did not grow.
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In this review article, we show that occurrence of fungicide resistance is one of the most important issues in modern agriculture. Fungicide resistance may be due to mutations of genes encoding fungicide targets (qualitative fungicide resistance) or to different mechanisms that are induced by sub-lethal fungicide stress. These mechanisms result in...
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Context 1
... as 1, 5 or 10 ppm, they were able to grow on plates containing 50 ppm of this fungicide. The fact that growth of isolates on high fungicide doses depended on their previous adaptation level indicates that quantitative resistance had developed, and that mechanisms allowing the fungus to cope with the fungicide are activated to a different extent (Fig. 4A). In accordance with the fact that efflux pumps show broad substrate specificity, not only isolates adapted to strobilurins, but also those adapted to azole fungicides can also grow on plates containing high strobilurin concentrations (cross resistance) (Fig. 4B). Due to their broad substrate specificity, the activity of the ...Context 2
... allowing the fungus to cope with the fungicide are activated to a different extent (Fig. 4A). In accordance with the fact that efflux pumps show broad substrate specificity, not only isolates adapted to strobilurins, but also those adapted to azole fungicides can also grow on plates containing high strobilurin concentrations (cross resistance) (Fig. 4B). Due to their broad substrate specificity, the activity of the transporters can be visualized by using fluorescent dyes such as ethidium bromide or Hoechst 33342. This simple microscopic evaluation of hyphae allows assessing the efflux pump-mediated state of fungicide resistance (41). In strains that had not been adapted and were thus ...Context 3
... Camptotheca acuminata and the plant pathogenic fungus Cercospora kikuchii. Transformants overexpressing this gene displayed decreased sensitivity to these compounds and to different fungicides, including azoles. The results indicate that the MSF multidrug transporter Bcmfs1 is involved in protection against natural toxins and fungicides (21) (Fig. ...Context 4
... together, the examples described here show that -in addition to mutations conferring fungicide resistance -efflux- Fig. 4A; I, II and III) were allowed to adapt to different concentrations ( Fig. 4A; 1, 5 and 10 ppm) of a strobilurin fungicide and plated out on agar plates containing 50 ppm of the same fungicide. Non-adapted control isolates ( Fig. 4A; 0) were unable to grow. Isolates adapted to three different strobilurin fungicides ( Fig. 4B; positions ...Context 5
... together, the examples described here show that -in addition to mutations conferring fungicide resistance -efflux- Fig. 4A; I, II and III) were allowed to adapt to different concentrations ( Fig. 4A; 1, 5 and 10 ppm) of a strobilurin fungicide and plated out on agar plates containing 50 ppm of the same fungicide. Non-adapted control isolates ( Fig. 4A; 0) were unable to grow. Isolates adapted to three different strobilurin fungicides ( Fig. 4B; positions b, c and d) and an isolate adapted to an azole fungicide ( Fig. 4B; position e) ...Context 6
... together, the examples described here show that -in addition to mutations conferring fungicide resistance -efflux- Fig. 4A; I, II and III) were allowed to adapt to different concentrations ( Fig. 4A; 1, 5 and 10 ppm) of a strobilurin fungicide and plated out on agar plates containing 50 ppm of the same fungicide. Non-adapted control isolates ( Fig. 4A; 0) were unable to grow. Isolates adapted to three different strobilurin fungicides ( Fig. 4B; positions b, c and d) and an isolate adapted to an azole fungicide ( Fig. 4B; position e) were able to grow on a plate containing 50 ppm of a strobilurin fungicide. A non-adapted control isolate ( Fig. 4B; position a) did not ...Context 7
... resistance -efflux- Fig. 4A; I, II and III) were allowed to adapt to different concentrations ( Fig. 4A; 1, 5 and 10 ppm) of a strobilurin fungicide and plated out on agar plates containing 50 ppm of the same fungicide. Non-adapted control isolates ( Fig. 4A; 0) were unable to grow. Isolates adapted to three different strobilurin fungicides ( Fig. 4B; positions b, c and d) and an isolate adapted to an azole fungicide ( Fig. 4B; position e) were able to grow on a plate containing 50 ppm of a strobilurin fungicide. A non-adapted control isolate ( Fig. 4B; position a) did not ...Context 8
... concentrations ( Fig. 4A; 1, 5 and 10 ppm) of a strobilurin fungicide and plated out on agar plates containing 50 ppm of the same fungicide. Non-adapted control isolates ( Fig. 4A; 0) were unable to grow. Isolates adapted to three different strobilurin fungicides ( Fig. 4B; positions b, c and d) and an isolate adapted to an azole fungicide ( Fig. 4B; position e) were able to grow on a plate containing 50 ppm of a strobilurin fungicide. A non-adapted control isolate ( Fig. 4B; position a) did not ...Context 9
... same fungicide. Non-adapted control isolates ( Fig. 4A; 0) were unable to grow. Isolates adapted to three different strobilurin fungicides ( Fig. 4B; positions b, c and d) and an isolate adapted to an azole fungicide ( Fig. 4B; position e) were able to grow on a plate containing 50 ppm of a strobilurin fungicide. A non-adapted control isolate ( Fig. 4B; position a) did not ...Similar publications
In this review article, we show that occurrence of fungicide resistance is one of the most important issues in modern agriculture. Fungicide resistance may be due to mutations of genes encoding fungicide targets (qualitative fungicide resistance) or to different mechanisms that are induced by sub-lethal fungicide stress. These mechanisms result in...
Citations
... The widespread use of fungicides to control and prevent damage due to pathogenic fungi often results in the development of fungicideresistant strains, necessitating the need for new disease control strategies. An alternative to help overcome resistance has been to apply fungicide mixtures to combat one or more pathogens at various stages of the life cycle (Deising et al., 2008). ...
The aim of this study was to evaluate whether alterations in food availability compromise the metabolic homeostasis of honey bees exposed to three fungicides alone or together. Ten honey bee colonies were utilized, with half receiving energy-protein supplementation for 15 weeks while another five colonies had their protein supply reduced with pollen traps. Subsequently, forager bees were collected and exposed by contact to 1 or 7 µg of bixafen, prothioconazole, and trifloxystrobin, either individually or in combination. After 48 hours, abdomens without the intestine was used for the analysis of expression of antioxidant genes (SOD-1, CAT, and GPX-1), detoxification genes (GST-1 and CYP306A1), the storage protein gene vitellogenin, and immune system antimicrobial peptide genes (Defensin-1, Abaecin, Hymenoptaecin, and Apidaecin), through real-time PCR. All pesticide treatments induced changes in gene expression, with bixafen showing the most prominent upregulation. Exposure to 1 µg of each of the three pesticides resulted in upregulation of genes associated with detoxification and nutrition processes, and downregulation of immune system genes. When the three pesticides were combined at a dose of 7 µg each, there was a pronounced downregulation of all genes. Dietary supplementation led to a slight reduction in gene expression alterations provoked by the fungicides.
... Despite the global trend towards the ecologization of agricultural production, treatment with fungicides remains the most common and effective method of combating the disease [2]. The widespread repeated use of pesticides within one season is accompanied by a number of destructive consequences, including a decrease in the sensitivity of the phytopathogen and the appearance of resistant strains [3]. The resistance to fungicides in the pathogen population develops more rapidly at a high initial frequency of strains resistant to the active ingredient of fungicide. ...
... The use of fungicides based on strobilurins and triazoles stabilized the phytosanitary state of barley crops in the 1980s-1990s thanks to the enrichment of protection technologies with drugs containing fundamentally new active ingredients with high specificity, a wide range of controlled phytopathogens, and a prolonged period of protection. Today, the accumulation of the most resistant phytopathogenic microorganisms in agrocenoses leads to a decrease in the effectiveness of treatments [3]. The increase in application rates and in the frequency of treatments, as well as the application of new fungicides, lead to the accumulation of resistant strains and stimulates their spread [4]. ...
... Fungicides resistance can emerge in populations of target plant pathogenic fungi soon after exposure to a fungicide (Deising et al. 2008;Lucas et al. 2015;Yin et al. 2023). Fungicide resistance can be defined as "the stable new and heritable trait associated with reduction in the sensitivity of an individual fungus to a specific fungicide" (Delp and Dekker 1985;McGrath 2004). ...
... Under the effect of single-site fungicides, where a single mutation in the target protein can confer a high level of resistance, a qualitative phenotypic change in the pathogen population usually results in two populations with a bimodal distribution for sensitivity. With multi-site fungicides, or with some single-site fungicides where more than one allele contributes to resistance, a unimodal distribution with quantitative changes is observed (Georgopoulos and Skylakakis 1986;Deising et al. 2008;Lucas et al. 2015). In both cases, directional selection is observed towards lower sensitivity acting on discrete variation, in the case of qualitative resistance. ...
... In both cases, directional selection is observed towards lower sensitivity acting on discrete variation, in the case of qualitative resistance. In contrast, a continuous distribution for quantitative resistance is observed by gradual changes towards resistance over time (Georgopoulos and Skylakakis 1986;Deising et al. 2008;Lucas et al. 2015). ...
Fungicide resistance is an alarming challenge for the Brazilian tropical agricultural systems, with major implications for food
safety, human and animal health, as well as for the environment. This review explores strategies to address fungicide resistance
within the Brazilian agroecosystem context. We examined historical and current scenarios of fungicide resistance in
the Brazilian agroecosystems and the approaches to delay the emergence and mitigate the selection of resistant variants. Our
review indicates that the prevalence of resistance in field populations of key plant pathogens in Brazil was due to failures in
the implementation of preventive measures. To address this issue, alternative evolutionary-smart strategies against fungicide
resistance are proposed, emphasizing institutional actions and public policies. Crucial steps involve strengthening national
networks for large-scale foliar and seed fungicide efficacy testing and resistance monitoring, as well as imposing tighter
restrictions on the labeling of high-risk single-active formulations. Additionally, the integration of non-chemical disease
management strategies and the establishment of a centralized database and information system on fungicide resistance in
Brazil are identified as essential for effective resistance monitoring and informed decision-making. To enhance fungicide
resistance management, the adoption of a warning system (e.g., based on aerobiology- or on weather-monitoring) for predicting
disease epidemics and minimizing fungicide applications is recommended. Increased funding, collaboration, mandatory
reporting, and capacity building are required to overcome these challenges. In addition, promoting integrated disease
management approaches is vital. By implementing these tailored strategies, Brazil can actively contribute to safeguarding
its food safety, protecting human and animal health, and preserving the delicate balance of its unique agroecosystem. The
adoption of evolutionary-smart strategies against fungicide resistance will prolong fungicide efficacy, reduce economic costs,
and minimize environmental impacts, ensuring sustainable and resilient agriculture in Brazil.
... Several measures can be implemented to manage the N. dimidiatumrelated disease in dragon fruit cultivation, such as removing infected leaves and controlling humidity, which has proven to be effective [3]. Whilst fungicides have demonstrated potential in managing brown spot disease, their application can yield detrimental consequences for both the environment and human well-being and may facilitate the emergence of fungus-resistant strains [41]. The filamentous fungi belonging to the Trichoderma spp. ...
Dragon fruit cultivation encounters significant challenges due to the brown spot disease caused by Neoscytalidium dimidiatum, resulting in reduced yield and quality. In this study, we successfully isolated and identified N. dimidiatum as the causal agent of this disease in Long An, Vietnam. Concerns about the potential adverse effects of fungicide administration on the ecosystem and human well-being have prompted the exploration of alternative approaches. Trichoderma spp., a group of filamentous fungi, have emerged as promising biocontrol agents due to their competitive nature and ability to induce systemic resistance. Fifteen isolates of Trichoderma spp. were evaluated through a dual culture assay and indicated that Trichoderma viride (TDF2), Trichoderma asperellum (TDF5), and Trichoderma harzianum (TC1) exhibited significant antagonistic properties against N. dimidiatum. These isolates effectively inhibited the growth of N. dimidiatum in vitro, with efficacy ranging from 85.05% to 88.35%. Potted experiments further demonstrated that pre-treatment with Trichoderma spp. exhibited the highest level of effectiveness. This approach provided a competitive advantage over the soil-borne pathogen, resulting in a remarkable reduction in disease index by 70.25-75.71%, thus achieving effective disease management. While co-treatment of Trichoderma spp. and N. dimidiatum showed some potential in reducing disease severity, its efficacy was found to be suboptimal compared to pre-treatment. In summary, the Trichoderma spp. isolates investigated in this study have demonstrated their potential in managing brown spot disease, indicating their potential utility as biocontrol agents against N. dimidiatum infection in dragon fruit cultivation.
... Recent advancements in genetic studies show that the development of fungicide resistance is primarily attributed to adaptive changes at the molecular level. These range from point mutations, genomic plasticity, upregulation of transcription factors, and several underlying mutative responses (Deising et al. 2008). Adaptive mechanisms responsible for the development of fungicide resistance typically vary based on the geographic location of the fungal pathogen, the frequency of fungicidal exposure, and susceptibility to mutations (Chen et al. 2014;He et al. 2019). ...
Demethylation inhibitors (DMI) fungicides are commonly used to mitigate fungal diseases in crops by inhibiting ergosterol biosynthesis. Alternaria alternata and Alternaria tenuissima are fungal plant pathogens being controlled with DMIs. However, with unregulated use of fungicides, reports on reduced sensitivity to DMIs have been documented in these fungal species. Previous studies have shown the accumulation of point mutations in CYP51 and CYP61 genes that are involved in ergosterol biosynthesis to the development of resistance to DMI fungicides. Understanding the phylogeographic trends of isolates based on the DMI gene targets is critical to identify sustainable management strategies against fungicide resistance. In this study, a phylogenetic approach was used to determine the association of geographic origin of isolates with fungicide resistance across A. alternata and A. tenuissima isolates. Phylogeographic and haplotype analyses revealed genetic patterns in CYP51 and CYP61, associated with DMI resistance. Generally, clusters formed within specific geographic areas such as Asia and North America. Moreover, nucleotide variation estimates revealed the presence of polymorphic nucleotide bases in response to DMI exposure as a selection pressure. These results provided insights in further testing in vitro assays regarding the selection patterns associated with specific regions.
... Monoculture and climate change favour the emergence of new, highly virulent pathogen variants that reduce yield, posing a serious threat to global food security (Vel asquez et al., 2018). Historically, foliar diseases of cereals have been controlled by (i) eradicating alternate hosts (Barnes et al., 2020), (ii) breeding resistant cultivars (Hafeez et al., 2021) and, more recently, (iii) spraying with systemic fungicides (Deising et al., 2008). Fungicides create selection pressure that encourages the emergence of fungicide-resistant crop pathogen variants (Tucker et al., 2015) as well as environmentally ubiquitous yeast and Aspergillus variants which can transfer to humans to cause infections resistant to medical antifungals (Castelo-Branco et al., 2021;Gow et al., 2022;Rhodes et al., 2022). ...
Staying ahead of the arms race against rust and mildew diseases in cereal crops is essential to maintain and preserve food security. The methodological challenges associated with conventional resistance breeding are major bottlenecks for deploying resistance (R) genes in high-yielding crop varieties. Advancements in our knowledge of plant genomes, structural mechanisms, innovations in bioinformatics, and improved plant transformation techniques have alleviated this bottleneck by permitting rapid gene isolation, functional studies, directed engineering of synthetic resistance and precise genome manipulation in elite crop cultivars. Most cloned cereal R genes encode canonical immune receptors which, on their own, are prone to being overcome through selection for resistance-evading pathogenic strains. However, the increasingly large repertoire of cloned R genes permits multi-gene stacking that, in principle, should provide longer-lasting resistance. This review discusses how these genomics-enabled developments are leading to new breeding and biotechnological opportunities to achieve durable rust and powdery mildew control in cereals.
... Mutations in genes involved in metal ion binding can result in decreased binding affinity of proteins for metal ions, decreasing the effectiveness of the fungicide. This could lead to the development of resistance in fungal pathogens [39][40][41] . Minor effects of several other genes have also been reported to contribute to resistance, such as genes related to efflux pumps and detoxification as ATP binding cassette (ABC) transporters and cytochrome P450 proteins 14,42,43 . ...
Phytophthora crown rot (PhCR) caused by Phytophthora cactorum is one of the most damaging diseases of strawberry worldwide. Mefenoxam is one of the major fungicides currently used to manage PhCR. However, the emergence and spread of resistant isolates have made controlling the pathogen in the field problematic. In the present study, using whole genome sequencing analysis, mutations associated with mefenoxam-resistant isolates were identified in six different genomic regions of P. cactorum. The 95.54% reads from a sensitive isolate pool and 95.65% from a resistant isolate pool were mapped to the reference genome of P. cactorum P414. Four point mutations were in coding regions while the other two were in noncoding regions. The genes harboring mutations were functionally unknown. All mutations present in resistant isolates were confirmed by sanger sequencing of PCR products. For the rapid diagnostic assay, SNP-based high-resolution melting (HRM) markers were developed to differentiate mefenoxam-resistant P. cactorum from sensitive isolates. The HRM markers R3-1F/R3-1R and R2-1F/R2-1R were suitable to differentiate both sensitive and resistant profiles using clean and crude DNA extraction. None of the mutations associated with mefenoxam resistance found in this study were in the RNA polymerase subunit genes, the hypothesized target of this compound in oomycetes. Our findings may contribute to a better understanding of the mechanisms of resistance of mefenoxam in oomycetes since serves as a foundation to validate the candidate genes as well as contribute to the monitoring of P. cactorum populations for the sustainable use of this product.
... They act as inhibitors of β-tubulin assembly in mitosis, preventing cell division and subsequent growth. Benzimidazoles are active against many species of fungi and have been used for plant disease control since the late 1960s (Deising et al. 2008). Resistance to benomyl was first reported in 1967 in cucurbit powdery mildew in the United States (McGrath 2001), only two years after its first use. ...
Phyllosticta citricarpa is the causative agent of citrus black spot (CBS), a cosmetic fungal disease that has been reported in most of the citrus-growing regions of the world. The occurrence of CBS in orchards is predominantly controlled by the application of fungicides during the fruit susceptibility period. Benzimidazoles (benomyl and carbendazim) and toluamides (ethaboxam and zoxamide) are two systemic fungicide classes suitable for the control of CBS in South Africa. Both inhibit proper assembly of the fungal β-tubulin protein during mitosis, and resistance to these fungicides is primarily related to alterations in the binding sites on this target protein. In this study, P. citricarpa isolates with known resistance status were subjected to whole genome sequencing, the mutations conferring resistance to benomyl and zoxamide were examined and allele-specific primers targeting these mutations were developed. The allele-specific multiplex PCR assay for the detection of benomyl resistance in P. citricarpa will eliminate the need for laborious and time-consuming sensitivity assays or DNA sequencing.
... Dedalus® (tebuconazole), Lidal® (tetraconazole) and Topas® (penconazole), used to control powdery mildew in vineyards, are 1,2,4-triazole fungicides, a class of heterocyclic rings introduced in the 1970s. They act against the biosynthesis of ergosterol, an essential compound of the fungal membrane, as a mechanism of action against the target fungus (Deising et al. 2008). However, the effects of these molecules on soil bacteria has previously been documented (Zhang et al. 2014;Baćmaga et al. 2015;Sułowicz et al. 2016). ...
This study evaluates the capacity of commercial formulations of synthetic fungicides to inhibit grapevine bacterial growth when sprayed on vineyards to control diseases, such as downy mildew, powdery mildew and secondary rots. Fungicide sensitivity plate assays were carried out on bacteria isolated from vineyards that were also identified and characterized for their plant growth-promoting (PGP) traits and antifungal activity. The high taxonomic variability of bacteria screened with different chemical classes of fungicides is one new finding of this study. Seven out of 11 fungicides were able to inhibit the growth of bacteria at a concentration corresponding to the maximum dose allowed by law in spray treatments of vineyards. Bacterial sensitivity to each fungicide varied greatly. Many sensitive isolates displayed PGP traits and/or antagonistic activity. This study shows the potential impact of fungicidal treatments on grapevine bacterial microbiota. The involvement of bacteria beneficial to the growth and health of plants underlines the importance of this investigation. Our data reveal that the control of a certain disease may be possible using fungicides that have no or low impact on natural non-target microbiota. Understanding the action mechanisms of the active ingredients in these products is a priority for the development of new eco-friendly pesticides.
... Powdery mildew fungi resistant to these and other chemical classes of fungicides emerge typically within a few years after first field usage (Vielba-Fernández et al. 2020). Resistance to fungicides often relies on single nucleotide variations in the genes encoding the fungal target proteins, resulting in single amino acid exchanges that completely prevent fungicide action (qualitative fungicide resistance), or on a variety of other mechanisms that result in varying levels of resistance (quantitative fungicide resistance) (Deising et al. 2008). ...
The powdery mildew fungi (Erysiphaceae) are globally distributed plant pathogens with a range of more than 10,000 plant hosts. In this review, we discuss the long- and short-term evolution of these obligate biotrophic fungi and outline their diversity with respect to morphology, lifestyle, and host range. We highlight their remarkable ability to rapidly overcome plant immunity, evolve fungicide resistance, and broaden their host range, e.g., through adaptation and hybridization. Recent advances in genomics and proteomics, particularly in cereal powdery mildews (genus Blumeria), provided first insights into mechanisms of genomic adaptation in these fungi. Transposable elements play key roles in shaping their genomes, where even close relatives exhibit diversified patterns of recent and ongoing transposon activity. These transposons are ubiquitously distributed in the powdery mildew genomes, resulting in a highly adaptive genome architecture lacking obvious regions of conserved gene space. Transposons can also be neo-functionalized to encode novel virulence factors, particularly candidate secreted effector proteins, which may undermine the plant immune system. In cereals like barley and wheat, some of these effectors are recognized by plant immune receptors encoded by resistance genes with numerous allelic variants. These effectors determine incompatibility ("avirulence") and evolve rapidly through sequence diversification and copy number variation. Altogether, powdery mildew fungi possess plastic genomes that enable their fast evolutionary adaptation towards overcoming plant immunity, host barriers, and chemical stress such as fungicides, foreshadowing future outbreaks, host range shifts and expansions as well as potential pandemics by these pathogens.
