scholarly journals Detection and monitoring of fungicide resistance in plant pathogens using pyrosequencing

2016 ◽  
Vol 41 (1) ◽  
pp. 78-87 ◽  
Author(s):  
Makoto Fujimura ◽  
Shinpei Banno ◽  
Masayuki Kamei ◽  
Yohei Ishigami ◽  
Yoshihito Tsukada
Keyword(s):  
Fungicide Resistance ◽  
Plant Pathogens

scholarly journals When time really is money: in situ quantification of the strobilurin resistance mutation G143A in the wheat pathogen Blumeria graminis f. sp. tritici

2020 ◽  
Author(s):  
Kejal N Dodhia ◽  
Belinda A Cox ◽  
Richard P Oliver ◽  
Francisco J Lopez-Ruiz
Keyword(s):  
Fungicide Resistance ◽  
Plant Pathogens ◽  
Resistance Mutation ◽  
Digital Pcr ◽  
Blumeria Graminis ◽  
Diagnostic Methods ◽  
Sample Collection ◽  
Specific Pcr ◽  
Field Samples

AbstractBackgroundThere has been an inexorable increase in the incidence of fungicide resistance in plant pathogens in recent years. Control of diseases and the management of resistance would be greatly aided by rapid diagnostic methods. Quantitative allele specific PCR (ASqPCR) is an ideal technique for the analysis of fungicide resistance in the field as it can both detect and quantify the frequency of mutations associated with fungicide resistance. We have applied this technique to the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), an obligate biotrophic fungus that causes wheat powdery mildew and is responsible for up to 25% yield loss annually. In Australia, strobilurin resistant Bgt was first discovered in samples from Tasmania and Victoria in 2016. Molecular analysis revealed a nucleotide transversion in the cytochrome bc1 enzyme (cytb) complex, resulting in a substitution of alanine for glycine at position 143 (G143A) in Cytb.ResultsWe have developed an in-field ASqPCR assay that can quantify both the resistant (A143) and sensitive (G143) cytb alleles down to 1.67% in host and Bgt DNA mixtures within 90 min of sample collection. The in situ analysis of field samples collected during a survey in Tasmania revealed A143 frequencies ranging between 9-100%. We validated the analysis with a newly developed laboratory based digital PCR assay and found no significant differences between the two methods.ConclusionWe have successfully developed an in-field quantification method, for a QoI resistant allele, by pairing an ASqPCR assay on a lightweight qPCR instrument with a quick DNA extraction method. The deployment of this type of methodologies in the field can contribute to the effective in-season management of fungicide resistance.

scholarly journals Evidence of Selection for Fungicide Resistance in Zymoseptoria tritici Populations on Wheat in Western Oregon

Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 483-489 ◽  
Author(s):  
Laura E. Hayes ◽  
Kathryn E. Sackett ◽  
Nicole P. Anderson ◽  
Michael D. Flowers ◽  
Christopher C. Mundt
Keyword(s):  
Fungicide Resistance ◽  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Resistance Evolution ◽  
Regional Control ◽  
Selection For ◽  
Moderately Resistant

Plant pathogens pose a major challenge to maintaining food security in many parts of the world. Where major plant pathogens are fungal, fungicide resistance can often thwart regional control efforts. Zymoseptoria tritici, causal agent of Septoria tritici blotch, is a major fungal pathogen of wheat that has evolved resistance to chemical control products in four fungicide classes in Europe. Compared with Europe, however, fungicide use has been less and studies of fungicide resistance have been infrequent in North American Z. tritici populations. Here, we confirm first reports of Z. tritici fungicide resistance evolution in western Oregon through analysis of the effects of spray applications of propiconazole and an azoxystrobin + propiconazole mixture during a single growing season. Frequencies of strobilurin-resistant isolates, quantified as proportions of G143A mutants, were significantly higher in azoxystrobin-sprayed plots compared with plots with no azoxystrobin treatment at two different locations and were significantly higher in plots of a moderately resistant cultivar than in plots of a susceptible cultivar. Thus, it appears that western Oregon Z. tritici populations have the potential to evolve levels of strobilurin resistance similar to those observed in Europe. Although the concentration of propiconazole required to reduce pathogen growth by 50% values were numerically greater for isolates collected from plots receiving propiconazole than in control plots, this effect was not significant (P > 0.05).

scholarly journals At Least Two Origins of Fungicide Resistance in Grapevine Downy Mildew Populations

2007 ◽  
Vol 73 (16) ◽  
pp. 5162-5172 ◽  
Author(s):  
Wei-Jen Chen ◽  
François Delmotte ◽  
Sylvie Richard Cervera ◽  
Lisette Douence ◽  
Charles Greif ◽  
...  
Keyword(s):  
Plant Pathogen ◽  
Fungicide Resistance ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Plasmopara Viticola ◽  
Isolated Populations ◽  
Grapevine Downy Mildew ◽  
First Case ◽  
Wide Range ◽  
Pathogen Populations

ABSTRACT Quinone outside inhibiting (QoI) fungicides represent one of the most widely used groups of fungicides used to control agriculturally important fungal pathogens. They inhibit the cytochrome bc 1 complex of mitochondrial respiration. Soon after their introduction onto the market in 1996, QoI fungicide-resistant isolates were detected in field plant pathogen populations of a large range of species. However, there is still little understanding of the processes driving the development of QoI fungicide resistance in plant pathogens. In particular, it is unknown whether fungicide resistance occurs independently in isolated populations or if it appears once and then spreads globally by migration. Here, we provide the first case study of the evolutionary processes that lead to the emergence of QoI fungicide resistance in the plant pathogen Plasmopara viticola. Sequence analysis of the complete cytochrome b gene showed that all resistant isolates carried a mutation resulting in the replacement of glycine by alanine at codon 143 (G143A). Phylogenetic analysis of a large mitochondrial DNA fragment including the cytochrome b gene (2,281 bp) across a wide range of European P. viticola isolates allowed the detection of four major haplotypes belonging to two distinct clades, each of which contains a different QoI fungicide resistance allele. This is the first demonstration that a selected substitution conferring resistance to a fungicide has occurred several times in a plant-pathogen system. Finally, a high population structure was found when the frequency of QoI fungicide resistance haplotypes was assessed in 17 French vineyards, indicating that pathogen populations might be under strong directional selection for local adaptation to fungicide pressure.

scholarly journals Effectors as Tools in Disease Resistance Breeding Against Biotrophic, Hemibiotrophic, and Necrotrophic Plant Pathogens

2014 ◽  
Vol 27 (3) ◽  
pp. 196-206 ◽  
Author(s):  
Vivianne G. A. A. Vleeshouwers ◽  
Richard P. Oliver
Keyword(s):  
Fungicide Resistance ◽  
Plant Pathogens ◽  
Functional Characterization ◽  
Resistance Breeding ◽  
World Population ◽  
Breeding Programs ◽  
Genome Wide ◽  
Disease Resistance Breeding ◽  
Pathogen Populations ◽  
New Strategies

One of most important challenges in plant breeding is improving resistance to the plethora of pathogens that threaten our crops. The ever-growing world population, changing pathogen populations, and fungicide resistance issues have increased the urgency of this task. In addition to a vital inflow of novel resistance sources into breeding programs, the functional characterization and deployment of resistance also needs improvement. Therefore, plant breeders need to adopt new strategies and techniques. In modern resistance breeding, effectors are emerging as tools to accelerate and improve the identification, functional characterization, and deployment of resistance genes. Since genome-wide catalogues of effectors have become available for various pathogens, including biotrophs as well as necrotrophs, effector-assisted breeding has been shown to be successful for various crops. “Effectoromics” has contributed to classical resistance breeding as well as for genetically modified approaches. Here, we present an overview of how effector-assisted breeding and deployment is being exploited for various pathosystems.

scholarly journals Growth Potential of Different Fungicide Resistant Alternaria solani Isolates of Tomato Leaf Blight Pathogen, under In Vitro, in the Presence of Different Fungicide, Growth Temperature and pH Ion Concentration

2020 ◽  
Vol 2 (5) ◽  
Author(s):  
V. A. Chavan ◽  
S. G. Borkar ◽  
Nivedita A Kadam
Keyword(s):  
Growth Rate ◽  
Fungicide Resistance ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Alternaria Solani ◽  
Leaf Blight ◽  
Growth Potential ◽  
Resistant Isolate ◽  
Cross Resistance

Evolution of fungicide resistance in plant pathogens and cross resistance to other fungicides in such pathogens is one of major concerns in sustainable plant disease management. Frequent and unwarranted use of fungicides to control plant diseases not only pollute the earth soil and environment, but also causes the development of fungicide resistance in the plant pathogens, which makes it difficult to manage the plant disease. In India, particularly in western Maharashtra, Alternaria leaf blight pathogen of tomato developed resistance and cross resistance to various fungicides. How these fungicide resistant isolates grow in the different fungicidal environment is reported in the present investigation. Eight different fungicide resistant isolates of Alternaria solani responsible for causing leaf blight in tomato crop were tested for their growth potential, under in vitro condition, on the potato-dextrose-agar(PDA) growth media amended with different fungicides viz. Dithane M-45, Blitox, Kavach, Ridomil, Nativo, Bavistin, Captaf and Score. Different fungicide resistant isolates showed different pattern of growth i.e. complete inhibition of growth, reduced growth or enhancement of growth on different fungicide amended PDA media. The growth of Dithane M-45 resistant isolate was enhanced by fungicide Kavach and Bavistin while reduced by fungicide Blitox. The growth of this fungicide resistant isolate was completely inhibited by fungicide Ridomil, Nativo, Captaf and Score. The maximum enhancement of growth was for Nativo resistant isolate to Bavistin amended PDA media. Bavistin resistant isolate had decreased growth on all fungicides amended PDA media. The minimum reduction in growth was recorded for Kavach resistant isolate on Dithane M-45 fungicide amended PDA media. The growth rate (cm/day) of these fungicide resistant isolates was maximum at 220C temperature as compared to 25 and 300C temperature on the routine PDA growth medium. Captaf resistant isolate produced more growth followed by Nativo, Dithane M-45 and score resistant isolate. The minimum growth was observed for Blitox resistant isolate. As the temperature increases, the growth rate decreased. The growth of fungicide resistant isolates was favored by neutral pH of 7.0 and decreased toward the acidic and alkaline condition. Captaf resistant isolate produced more growth followed by Nativo and score resistant isolates. The minimum growth was produced by Blitox resistant isolate. More growth of fungicide resistant Alternaria isolate means production of more inoculum for disease initiation and spread which is favored at 22 °C temperature and further indicate which fungicide should be used to restrict/manage the growth of particular Alternaria fungicide resistant isolate.

scholarly journals Fungicide Resistance Evolution and Detection in Plant Pathogens: Plasmopara viticola as a Case Study

2021 ◽  
Vol 9 (1) ◽  
pp. 119
Author(s):  
Federico Massi ◽  
Stefano F. F. Torriani ◽  
Lorenzo Borghi ◽  
Silvia L. Toffolatti
Keyword(s):  
Fungicide Resistance ◽  
Plant Pathogens ◽  
Control Plant ◽  
Plasmopara Viticola ◽  
Life Cycles ◽  
Grapevine Downy Mildew ◽  
Resistance Evolution ◽  
Evolution Of Resistance ◽  
Monitoring Activities

The use of single-site fungicides to control plant pathogens in the agroecosystem can be associated with an increased selection of resistance. The evolution of resistance represents one of the biggest challenges in disease control. In vineyards, frequent applications of fungicides are carried out every season for multiple years. The agronomic risk of developing fungicide resistance is, therefore, high. Plasmopara viticola, the causal agent of grapevine downy mildew, is a high risk pathogen associated with the development of fungicide resistance. P. viticola has developed resistance to most of the fungicide classes used and constitutes one of the most important threats for grapevine production. The goals of this review are to describe fungicide resistance evolution in P. viticola populations and how to conduct proper monitoring activities. Different methods have been developed for phenotyping and genotyping P. viticola for fungicide resistance and the different phases of resistance evolution and life cycles of the pathogen are discussed, to provide a full monitoring toolkit to limit the spread of resistance. A detailed revision of the available tools will help in shaping and harmonizing the monitoring activities between countries and organizations.

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