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Gaucher M, Juillard A, Nguyen BH, Viller N, Ernenwein C, Marion D, Brisset MN, Bakan B. Formulated hydroxy fatty acids from fruit pomaces reduce apple scab development caused by Venturia inaequalis through a dual mode of action. Front Plant Sci 2024; 14:1322638. [PMID: 38259942 PMCID: PMC10800985 DOI: 10.3389/fpls.2023.1322638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/13/2023] [Indexed: 01/24/2024]
Abstract
The outermost hydrophobic layer of plants, i.e. the cuticle, is mainly composed of cutin, a polyester of hydroxy fatty acids with reported eliciting and/or antimicrobial activities for some of them. By-products of the fruit processing industry (fruit pomaces), often strongly enriched in cuticular material, are therefore a potential source of bioactive compounds for crop protection against pathogen attack. We investigated the utilization of tomato and apple pomaces in the development of a cutin-based biocontrol solution against apple scab, a major apple disease caused by Venturia inaequalis. Several cutin monomer extracts obtained through different strategies of depolymerization and purification were first compared for their ability to induce a targeted set of defense genes in apple seedlings after foliar application. After a step of formulation, some extracts were chosen for further investigation in planta and in vitro. Our results show that formulated cutin monomers could trigger a significant transcriptome reprogramming in apple plants and exhibit an antifungal effect on V. inaequalis. Cutin monomers-treated apple seedlings were significantly protected against infection by the apple scab agent. Altogether, our findings suggest that water-dispersed cutin monomers extracted from pomaces are potential new bio-based solutions for the control of apple scab.
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Affiliation(s)
- Matthieu Gaucher
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, Angers, France
| | - Anthony Juillard
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, Angers, France
| | - Bao-Huynh Nguyen
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, Angers, France
| | - Noémie Viller
- INRAE, Biopolymers Interactions Assemblies, Nantes, France SDP Rovensa Company, Laon, France
| | | | - Didier Marion
- INRAE, Biopolymers Interactions Assemblies, Nantes, France SDP Rovensa Company, Laon, France
| | | | - Bénédicte Bakan
- INRAE, Biopolymers Interactions Assemblies, Nantes, France SDP Rovensa Company, Laon, France
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Rocafort M, Srivastava V, Bowen JK, Díaz-Moreno SM, Guo Y, Bulone V, Plummer KM, Sutherland PW, Anderson MA, Bradshaw RE, Mesarich CH. Cell Wall Carbohydrate Dynamics during the Differentiation of Infection Structures by the Apple Scab Fungus, Venturia inaequalis. Microbiol Spectr 2023; 11:e0421922. [PMID: 37039647 PMCID: PMC10269774 DOI: 10.1128/spectrum.04219-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 03/15/2023] [Indexed: 04/12/2023] Open
Abstract
Scab, caused by the biotrophic fungal pathogen Venturia inaequalis, is the most economically important disease of apples. During infection, V. inaequalis colonizes the subcuticular host environment, where it develops specialized infection structures called runner hyphae and stromata. These structures are thought to be involved in nutrient acquisition and effector (virulence factor) delivery, but also give rise to conidia that further the infection cycle. Despite their importance, very little is known about how these structures are differentiated. Likewise, nothing is known about how these structures are protected from host defenses or recognition by the host immune system. To better understand these processes, we first performed a glycosidic linkage analysis of sporulating tubular hyphae from V. inaequalis developed in culture. This analysis revealed that the V. inaequalis cell wall is mostly composed of glucans (44%) and mannans (37%), whereas chitin represents a much smaller proportion (4%). Next, we used transcriptomics and confocal laser scanning microscopy to provide insights into the cell wall carbohydrate composition of runner hyphae and stromata. These analyses revealed that, during subcuticular host colonization, genes of V. inaequalis putatively associated with the biosynthesis of immunogenic carbohydrates, such as chitin and β-1,6-glucan, are downregulated relative to growth in culture, while on the surface of runner hyphae and stromata, chitin is deacetylated to the less-immunogenic carbohydrate chitosan. These changes are anticipated to enable the subcuticular differentiation of runner hyphae and stromata by V. inaequalis, as well as to protect these structures from host defenses and recognition by the host immune system. IMPORTANCE Plant-pathogenic fungi are a major threat to food security. Among these are subcuticular pathogens, which often cause latent asymptomatic infections, making them difficult to control. A key feature of these pathogens is their ability to differentiate specialized subcuticular infection structures that, to date, remain largely understudied. This is typified by Venturia inaequalis, which causes scab, the most economically important disease of apples. In this study, we show that, during subcuticular host colonization, V. inaequalis downregulates genes associated with the biosynthesis of two immunogenic cell wall carbohydrates, chitin and β-1,6-glucan, and coats its subcuticular infection structures with a less-immunogenic carbohydrate, chitosan. These changes are anticipated to enable host colonization by V. inaequalis and provide a foundation for understanding subcuticular host colonization by other plant-pathogenic fungi. Such an understanding is important, as it may inform the development of novel control strategies against subcuticular plant-pathogenic fungi.
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Affiliation(s)
- Mercedes Rocafort
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Vaibhav Srivastava
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm, Sweden
| | - Joanna K. Bowen
- The New Zealand Institute for Plant and Food Research Limited, Mount Albert Research Centre, Auckland, New Zealand
| | - Sara M. Díaz-Moreno
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm, Sweden
| | - Yanan Guo
- Laboratory of Molecular Plant Pathology, School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Vincent Bulone
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm, Sweden
- School of Food, Agriculture and Wine, The University of Adelaide, Waite Campus, Adelaide, South Australia, Australia
| | - Kim M. Plummer
- Department of Animal, Plant and Soil Sciences, AgriBio, Centre for AgriBiosciences, La Trobe University, Bundoora, Melbourne, Victoria, Australia
| | - Paul W. Sutherland
- The New Zealand Institute for Plant and Food Research Limited, Mount Albert Research Centre, Auckland, New Zealand
| | - Marilyn A. Anderson
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, Victoria, Australia
| | - Rosie E. Bradshaw
- Laboratory of Molecular Plant Pathology, School of Natural Sciences, Massey University, Palmerston North, New Zealand
- Bioprotection Aotearoa, Massey University, Palmerston North, New Zealand
| | - Carl H. Mesarich
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
- Bioprotection Aotearoa, Massey University, Palmerston North, New Zealand
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González-Domínguez E, Caffi T, Rossi V, Salotti I, Fedele G. Plant Disease Models and Forecasting: Changes in Principles and Applications Over the Last 50 Years. Phytopathology 2023; 113:678-693. [PMID: 36624723 DOI: 10.1094/phyto-10-22-0362-kd] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This review gives a perspective of selected advances made since the middle of the 20th century in plant disease modeling, and the associated increase in the number of models published during that time frame. This progress can be mainly attributed to advances in (i) sensors and automatic environmental data collection technology, (ii) instrumentation and methods for studying botanical epidemiology, and (iii) data analytics and computer science. We review the evolution of techniques for developing data-based (empirical) models and process-based (mechanistic) models using the wheat rusts as a case study. We also describe the increased importance of knowledge about biological processes for plant disease modeling by using apple scab as a second case study. For both wheat rusts and apple scab, we describe how the models have evolved over the last 50 years by considering certain milestones that have been achieved in disease modeling. Finally, we describe how plant disease models are used as part of a multi-modeling approach to develop decision-making tools in the application of integrated pest management.
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Affiliation(s)
| | - Tito Caffi
- DiProVeS, Università Cattolica del Sacro Cuore di Piacenza, via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Vittorio Rossi
- DiProVeS, Università Cattolica del Sacro Cuore di Piacenza, via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Irene Salotti
- DiProVeS, Università Cattolica del Sacro Cuore di Piacenza, via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Giorgia Fedele
- DiProVeS, Università Cattolica del Sacro Cuore di Piacenza, via Emilia Parmense 84, 29122 Piacenza, Italy
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Sestras RE, Sestras AF. Quantitative Traits of Interest in Apple Breeding and Their Implications for Selection. Plants (Basel) 2023; 12:903. [PMID: 36840249 PMCID: PMC9964287 DOI: 10.3390/plants12040903] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Apple breeding is a laborious and long-lasting process that requires qualified resources, land, time, and funds. In this study, more than 5000 F1 apple hybrids from direct and testcrosses were analyzed. The results revealed how the phenotypic expression of the main quantitative traits of interest assessed in five half-sib families was controlled by the additive genetic effects and by non-additive effects of dominance and epistasis. The statistical number of hybrids required to ensure efficient selection increased exponentially with the number of desirable traits. The minimum number of progenies required to obtain a hybrid with associated quantitative traits of agronomic interest was highly variable. For two independent traits essential in selection (fruit size and quality), but incorporated together in the same hybrid, the statistical number was between about 30 and 300. If three more cumulative traits were added (a large number of fruits per tree, resistance/tolerance to apple scab, and powdery mildew attack), the limits increased to between 1500 and 18,000. The study highlighted the need for new apple varieties due to the narrowing of the genetic diversity of the cultivated species and how the choice of parents used in hybridizations (as well as the objectives pursued in the selection) can increase the efficiency of apple breeding.
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Affiliation(s)
- Radu E. Sestras
- Department of Horticulture and Landscape, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 3–5 Manastur Street, 400372 Cluj-Napoca, Romania
| | - Adriana F. Sestras
- Department of Forestry, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 3–5 Manastur Street, 400372 Cluj-Napoca, Romania
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Rancāne R, Valiuškaitė A, Zagorska V, Komašilovs V, Rasiukevičiūtė N. The Overall Environmental Load and Resistance Risk Caused by Long-Term Fungicide Use to Control Venturia inaequalis in Apple Orchards in Latvia. Plants (Basel) 2023; 12:450. [PMID: 36771537 PMCID: PMC9920844 DOI: 10.3390/plants12030450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 06/18/2023]
Abstract
Apple orchards are perennially planted where pesticides are applied to control numerous pests and diseases. The extensive long-term use of fungicides can lead to overall environmental load and resistance risk. This study aims to assess which fungicide-active substances have been used more intensively in the last decade in Latvia, evaluating the overall environmental load using the Pesticide Load Indicator (PLI). It was essential to see whether the amount of active substance usage rises, how it correlates with the total changes of the PLI and which substances are with the highest scores. The other issue was to test the sensitivity of Venturia inaequalis populations to systemic fungicides. Six full-bearing apple orchards that reflected local plant protection practices were selected from the different growing regions of Latvia to analyze fungicide use from 2012 to 2021 and test V. inaequalis populations' sensitivity to systemic substances difenoconazole and cyprodinil. The PLI demonstrated that the protective fungicides were the most crucial group overall, with the highest potential impact on the environment and human health. Systemic fungicides had a relatively lower environmental impact, but after long-term use, the pathogen population's sensitivity to difenoconazole and cyprodinil was reduced. Introducing new fungicide classes and biological control agents could help growers improve plant protection strategies against V. inaequalis, reducing the risk of resistance and environmental load.
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Affiliation(s)
- Regīna Rancāne
- Lithuanian Research Centre for Agriculture and Forestry, Institute of Horticulture, Kaunas District, LT-54333 Babtai, Lithuania
| | - Alma Valiuškaitė
- Lithuanian Research Centre for Agriculture and Forestry, Institute of Horticulture, Kaunas District, LT-54333 Babtai, Lithuania
| | - Viktorija Zagorska
- Institute for Plant Protection Research “Agrihorts”, Latvia University of Life Sciences and Technologies, LV-3004 Jelgava, Latvia
| | - Vitālijs Komašilovs
- Faculty of Information Technologies, Latvia University of Life Sciences and Technologies, LV-3001 Jelgava, Latvia
| | - Neringa Rasiukevičiūtė
- Lithuanian Research Centre for Agriculture and Forestry, Institute of Horticulture, Kaunas District, LT-54333 Babtai, Lithuania
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Nasonov AI, Yakuba GV, Astapchuk IL. Sensitivity of Krasnodar Venturia inaequalis Populations to the Sterol Demethylation Inhibitor Difenoconazole. Dokl Biol Sci 2022; 507:463-472. [PMID: 36781541 DOI: 10.1134/s001249662206014x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 02/15/2023]
Abstract
Difenoconazole sensitivity was assessed in three populations of the apple scab agent Venturia inaequalis of the Krasnodar region. One of the populations was fungicide naïve population; its sample was collected in natural habitats of the eastern crabapple Malus orientalis in foothills of the Severskii raion. The two other populations were from commercial orchards of the apple variety Reinette Simirenko (the Krasnoarmeiskii and Dinskoi raions), where fungicide treatments with various agents, including those with difenoconazole as an active ingredient, were performed on a regular basis. Single-spore V. inaequalis isolates were isolated from fresh leaves with signs of the disease or fallen leaves with fungal fruiting bodies. The median effective concentration (EC50) was defined as the concentration that halves the colony growth and was estimated in a series of in vitro experiments with 120 isolates. Difenoconazole (Score EC, 250 mg/L, Syngenta) was used at six concentrations: 0.005, 0.01, 0.025, 0.05, 0.5, and 1 mg a.i./L. Mean EC50 values were 0.0078 mg a.i./L in the natural population and 0.12 and 0.25 mg a.i./L in the orchard populations. Fungicide sensitivity was lower in both of the orchard populations; their resistance factors were estimated at 16 and 32. The proportion of sensitive and low-sensitive isolates differed between the two orchard populations. A discriminatory dose, or single-assessment concentration (SAC), of 0.01 mg a.i./L was proposed to simplify the laboratory monitoring of the difenoconazole sensitivity in V. inaequalis by using a test for relative growth (RG) of the mycelium. Comparable results were obtained with EC50 and RG at the discriminatory dose. The portion of isolates with RGs exceeding the threshold (RG > 70%) was 97% in one of the orchard populations. The results indicate that difenoconazole resistance develops in V. inaequalis populations from commercial orchards of the Krasnodar region.
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Affiliation(s)
- A I Nasonov
- North Caucasian Federal Research Center of Horticulture, Viniculture, and Wine Industry, Krasnodar, Russia.
| | - G V Yakuba
- North Caucasian Federal Research Center of Horticulture, Viniculture, and Wine Industry, Krasnodar, Russia.
| | - I L Astapchuk
- North Caucasian Federal Research Center of Horticulture, Viniculture, and Wine Industry, Krasnodar, Russia.
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Gaucher M, Heintz C, Cournol R, Juillard A, Bellevaux C, Cavaignac S, Coureau C, Giraud M, Le Maguet J, Bérud M, Koké E, Crété X, Lemarquand A, Orain G, Brisset MN. The Use of Potassium Phosphonate (KHP) for the Control of Major Apple Pests. Plant Dis 2022; 106:3166-3177. [PMID: 35596247 DOI: 10.1094/pdis-01-22-0183-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Phosphonate-based products have demonstrated diverse abilities to protect crops against pests, with various modes of action proposed. In this article, we specifically investigated potassium phosphonate (KHP) on apple crops. Its performance to control three major apple bioagressors (Venturia inaequalis, Erwinia amylovora, and Dysaphis plantaginea) was evaluated under semicontrolled conditions. The product was able to confer significant protection rates (40 to 75% for apple scab, 40% for fire blight, and 30% for rosy aphid), which can be explained by its more or less efficient biocidal activity against the three pests, and by its ability to induce apple immunity (pathogenesis-related proteins and secondary metabolites genes). A cumulative effect of treatments as well as the systemic behavior of the product was demonstrated. Fields trials against apple scab and the postharvest disease bull's eyes rot (Neofabraea vagabunda) were performed on different apple varieties by applying KHP combined with light pest management programs either reducing (dessert orchards) or suppressing (cider orchards) fungicide applications. KHP was able to reduce apple scab by 70 to 90% on shoots and young and harvested fruit, and bull's eyes rot by 70 to 90% on harvested fruit. Overall, our results indicate that KHP is useful for the protection of apple trees against its major pests by direct effect and by triggering the host defense system.
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Affiliation(s)
- Matthieu Gaucher
- IRHS-UMR1345, Université d'Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, F-49071, Beaucouzé, France
| | - Christelle Heintz
- IRHS-UMR1345, Université d'Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, F-49071, Beaucouzé, France
| | - Raphaël Cournol
- IRHS-UMR1345, Université d'Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, F-49071, Beaucouzé, France
| | - Anthony Juillard
- IRHS-UMR1345, Université d'Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, F-49071, Beaucouzé, France
| | | | | | | | | | | | | | | | | | | | | | - Marie-Noëlle Brisset
- IRHS-UMR1345, Université d'Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, F-49071, Beaucouzé, France
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Krasova N, Ozherelieva Z, Galasheva A, Lupin M. Production and Biological Assessment of VNIISPK Cultivars of Various Ploidy for the Zone of Temperate Continental Climate. Plants (Basel) 2022; 11:2770. [PMID: 36297793 PMCID: PMC9608241 DOI: 10.3390/plants11202770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Increasing the reliability of fruit crops in unstable weather conditions of a temperate continental climate has become particularly relevant. This research was carried out based on a bioresource collection from the Russian Research Institute of Fruit Crop Breeding (VNIISPK BRC). Apple cultivars (diploids and triploids) of different maturation periods were studied. Triploid cultivars (3×) of summer maturation were developed using diploid gametes of the 'Papirovka tetraploid' cultivar as a donor (2-4-4-4×), triploids of winter maturation were developed using 13-6-106 (Suvorovetz: open pollination), and 'Wealthy tetraploid' (2-4-4-4×) or 'Giant Spy' (2-4-4-4×) were used as donors of diploid gametes. 'Antonovka' and 'Melba' were taken as control cultivars. The aim of this work was to evaluate the apple breeding cultivars according to the main economic and biological indicators and to determine the threshold of resistance to unfavorable conditions of the winter period for possible cultivation in specific conditions of a temperate continental climate. As a result of using the method of modeling damaging factors, apple cultivars that withstood not only the critical temperatures of January, but also especially dangerous frosts after thaws at the end of winter were identified, with the stability of vital tissues at the level of 'Antonovka' (a control cultivar), scab immune cultivars (RVi6) 'Ivanovskoye', 'Zdorovie' and 'Pamyati Hitrovo', and immune triploids (3×) 'Vavilovskoye', 'Aleksandr Boyko', Rozhdestvenskoye' and 'Academic Saveliev'. During the whole winter, the winter resistance of summer scab immune triploids, 'Zhilinskoye', 'Maslovskoye', 'Yablochny Spas' and 'Spasskoye', was at the level of 'Antonovka', but was higher than 'Melba'. The high precocity of scab-immune cultivars, 'Afrodita', 'Ivanovskoye', 'Veniaminovskoye', and 'Yubiley Moskvy', and triploids 'Patriot' and 'Rozhdestvenskoye', have been identified. Triploid cultivars are superior to diploid cultivars and control 'Antonovka' in fruit size. According to the complex of characteristics, promising apple cultivars were identified for planting in intensive orchards of the temperate continental climate zones, namely 'Avgusta' and 'Solnyshko' (summer cultivars), and 'Aleksandr Boyko', 'Vavilovskoye', 'Venyaminovskoye', 'Ivanovskoye' and 'Rozhdestvenskoye' (winter cultivars).
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Sokolova O, Moročko-Bičevska I, Lācis G. Genetic Diversity of Venturia inaequalis in Latvia Revealed by Microsatellite Markers. Pathogens 2022; 11:pathogens11101165. [PMID: 36297222 PMCID: PMC9611756 DOI: 10.3390/pathogens11101165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/22/2022] Open
Abstract
Apple scab caused by the ascomycete Venturia inaequalis is an economically significant disease worldwide. The annual sexual reproduction of V. inaequalis leads to high variation, changes in the population's genetic structure and adaptations to the changing environment, including overcoming the host's resistance. The objective of this study is to characterise and assess the genetic diversity of V. inaequalis populations in two main apple-growing regions in Latvia. In total, 143 V. inaequalis isolates were collected from Latvia, six reference strains with known virulence were obtained from other countries, and all strains were genotyped by 12 SSR markers. The SSR markers were highly variable and informative, identifying 158 alleles that ranged from two to 29 per locus. The Bayesian clustering identified three genetic lineages among the Latvian isolates that did not correlate to the geographic origin, host genotype, organ (leaves or fruits) from which the pathogen was isolated, time of collection, and type of isolation (single conidium or ascospore). The possible relatedness to virulence was detected when reference strains with known virulence were included in the analysis. Our findings correspond with previous studies demonstrating that V. inaequalis in Europe has a high genetic diversity within populations, but low diversity among the populations.
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Affiliation(s)
- Olga Sokolova
- Institute of Horticulture, Latvia University of Life Sciences and Technologies, LV-3701 Dobele, Latvia
- Institute of Soil and Plant Sciences, Latvia University of Life Sciences and Technologies, Lielā str. 2, LV-3001 Jelgava, Latvia
- Correspondence:
| | - Inga Moročko-Bičevska
- Institute of Horticulture, Latvia University of Life Sciences and Technologies, LV-3701 Dobele, Latvia
| | - Gunārs Lācis
- Institute of Horticulture, Latvia University of Life Sciences and Technologies, LV-3701 Dobele, Latvia
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Leconte A, Tournant L, Muchembled J, Paucellier J, Héquet A, Deracinois B, Deweer C, Krier F, Deleu M, Oste S, Jacques P, Coutte F. Assessment of Lipopeptide Mixtures Produced by Bacillus subtilis as Biocontrol Products against Apple Scab ( Venturia inaequalis). Microorganisms 2022; 10:1810. [PMID: 36144412 DOI: 10.3390/microorganisms10091810] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/29/2022] [Accepted: 09/05/2022] [Indexed: 02/03/2023] Open
Abstract
Apple scab is an important disease conventionally controlled by chemical fungicides, which should be replaced by more environmentally friendly alternatives. One of these alternatives could be the use of lipopeptides produced by Bacillus subtilis. The objective of this work is to study the action of the three families of lipopeptides and different mixtures of them in vitro and in vivo against Venturia inaequalis. Firstly, the antifungal activity of mycosubtilin/surfactin and fengycin/surfactin mixtures was determined in vitro by measuring the median inhibitory concentration. Then, the best lipopeptide mixture ratio was produced using Design of Experiment (DoE) to optimize the composition of the culture medium. Finally, the lipopeptides mixtures efficiency against V. inaequalis was assessed in orchards as well as the evaluation of the persistence of lipopeptides on apple. In vitro tests show that the use of fengycin or mycosubtilin alone is as effective as a mixture, with the 50–50% fengycin/surfactin mixture being the most effective. Optimization of culture medium for the production of fengycin/surfactin mixture shows that the best composition is glycerol coupled with glutamic acid. Finally, lipopeptides showed in vivo antifungal efficiency against V. inaequalis regardless of the mixture used with a 70% reduction in the incidence of scab for both mixtures (fengycin/surfactin or mycosubtilin/surfactin). The reproducibility of the results over the two trial campaigns was significantly better with the mycosubtilin/surfactin mixture. The use of B. subtilis lipopeptides to control this disease is very promising.
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Cordero-Limon L, Shaw MW, Passey TA, Robinson JD, Xu X. Cross-resistance between myclobutanil and tebuconazole and the genetic basis of tebuconazole resistance in Venturia inaequalis. Pest Manag Sci 2021; 77:844-850. [PMID: 32926586 DOI: 10.1002/ps.6088] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/05/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Myclobutanil is one of the most widely used demethylation inhibitor (DMI) fungicides for the management of apple scab, caused by Venturia inaequalis. Strains of V. inaequalis resistant to myclobutanil have been reported across the world. Tebuconazole, another DMI fungicide, has been proposed as an alternative to myclobutanil, and the extent of cross-resistance with myclobutanil therefore needs to be evaluated. The sensitivity to tebuconazole and myclobutanil of a total of 40 isolates was determined. Half the isolates came from an isolated orchard which had never been sprayed with fungicides and half from orchards sprayed regularly with myclobutanil, but still with disease control problems. The progeny of a tebuconazole resistant (R) × sensitive (S) V. inaequalis cross were analyzed in order to improve understanding of the genetic control of tebuconazole sensitivity. RESULTS There is cross-resistance between myclobutanil and tebuconazole (r = 0.91; P < 0.001). Sensitivity to tebuconazole of the progeny of a R × S cross varied quantitatively in a pattern which implied at least two gene loci differing between the parental strains. In addition, the asymmetric distribution of the sensitivity in the progeny implied possible epistatic effects. CONCLUSION Resistance to myclobutanil and tebuconazole is strongly correlated. At least two genes are involved in the control of tebuconazole resistance in V. inaequalis.
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Affiliation(s)
- Laura Cordero-Limon
- School of Agriculture, Policy and Development, University of Reading, Reading, UK
- NIAB EMR, Kent, UK
| | - Michael W Shaw
- School of Agriculture, Policy and Development, University of Reading, Reading, UK
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12
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Prencipe S, Sillo F, Garibaldi A, Gullino ML, Spadaro D. Development of a Sensitive TaqMan qPCR Assay for Detection and Quantification of Venturia inaequalis in Apple Leaves and Fruit and in Air Samples. Plant Dis 2020; 104:2851-2859. [PMID: 32902358 DOI: 10.1094/pdis-10-19-2160-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A TaqMan quantitative PCR (qPCR) assay based on the translation elongation factor 1-α gene was developed for the quantification of Venturia inaequalis in leaves and fruits of Malus × domestica and in spore trap samples. The designed primers and hydrolysis probe amplified a specific 86-bp fragment for V. inaequalis. The specificity of the assay was tested using 35 strains of V. inaequalis and 20 different fungal species, including common pathogens of apple and other species of Venturia. The limit of detection was 20 fg, which is lower than a single genome of V. inaequalis. The selectivity of the assay was tested using DNA from three cultivars of Malus × domestica, and no influence on pathogen amplification was found. The assay was also validated for repeatability and reproducibility. With this assay, it was possible to detect and quantify V. inaequalis in four cultivars (Ambrosia, Florina, Golden Delicious, and Mondial Gala) in both symptomatic and asymptomatic leaves and in symptomatic Golden Delicious apple fruit stored for 2 months. Furthermore, the assay was successfully tested on spore trap samples originating from apple orchards. The quantification of the molecular assay when compared with the estimated number of V. inaequalis cells, using an optical microscope, showed a correlation coefficient of 0.8186. The developed technique could be used to detect V. inaequalis in asymptomatic samples without any cross-reaction with other fungal species. Furthermore, to improve the efficacy of disease management with a timely application of fungicides, this assay could be used for the analysis of spore trap samples by using an implemented extraction method.
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Affiliation(s)
- Simona Prencipe
- Department of Agricultural, Forestry and Food Sciences (DiSAFA), University of Torino, via Paolo Braccini 2, 10095, Grugliasco, Italy
| | - Fabiano Sillo
- Department of Agricultural, Forestry and Food Sciences (DiSAFA), University of Torino, via Paolo Braccini 2, 10095, Grugliasco, Italy
| | - Angelo Garibaldi
- Centre of Competence for the Innovation in the Agro-environmental Sector-AGROINNOVA, University of Turin, via Paolo Braccini 2, 10095, Grugliasco, Italy
| | - Maria Lodovica Gullino
- Department of Agricultural, Forestry and Food Sciences (DiSAFA), University of Torino, via Paolo Braccini 2, 10095, Grugliasco, Italy
- Centre of Competence for the Innovation in the Agro-environmental Sector-AGROINNOVA, University of Turin, via Paolo Braccini 2, 10095, Grugliasco, Italy
| | - Davide Spadaro
- Department of Agricultural, Forestry and Food Sciences (DiSAFA), University of Torino, via Paolo Braccini 2, 10095, Grugliasco, Italy
- Centre of Competence for the Innovation in the Agro-environmental Sector-AGROINNOVA, University of Turin, via Paolo Braccini 2, 10095, Grugliasco, Italy
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13
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Ayer KM, Choi MW, Smart ST, Moffett AE, Cox KD. The Effects of Succinate Dehydrogenase Inhibitor Fungicide Dose and Mixture on Development of Resistance in Venturia inaequalis. Appl Environ Microbiol 2020; 86:e01196-20. [PMID: 32631859 DOI: 10.1128/AEM.01196-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 06/28/2020] [Indexed: 11/20/2022] Open
Abstract
Understanding how fungicide application practices affect selection for fungicide resistance is imperative for continued sustainable agriculture. Here, we examined the effect of field applications of the succinate dehydrogenase inhibitor (SDHI) fluxapyroxad at different doses and mixtures on the SDHI sensitivity of Venturia inaequalis, the apple scab pathogen. Fungicide applications were part of selection programs involving different doses (high or low) and mixtures (with a second single-site fungicide or a multisite fungicide). These programs were tested in two apple orchards over 4 years to determine potential cumulative selection effects on resistance. Each year after program applications, apple scab lesions were collected, and relative growth assays were conducted to understand shifts in fluxapyroxad sensitivity. After 4 years, there was a trend toward a reduction in sensitivity to fluxapyroxad for most selection programs in comparison to that in the non-selective-pressure control. In most years, the selection program plots treated with low-dose fluxapyroxad applications resulted in a larger number of isolates with reduced sensitivity, supporting the use of higher doses for disease management. Few significant differences (P < 0.05) in fungicide sensitivity were observed between isolates collected from plots where fungicide mixtures were applied compared to that in untreated plots, supporting the use of multiple modes of action in field applications. In all, appropriate doses and mixtures may contribute to increased longevity of SDHI fungicides used on perennial crops like apples.IMPORTANCE Of much debate is the effect of fungicide application dose on resistance development, as fungicide resistance is a critical barrier to effective disease management in agricultural systems. Our field study in apples investigated the effect of fungicide application dose and mixture on the selection of succinate dehydrogenase inhibitor resistance in Venturia inaequalis, a fungal pathogen that causes the economically important disease apple scab. Understanding how to best delay the development of resistance can result in increased efficacy, fewer applications, and sustainable fungicide use. Results from this study may have relevance to other perennial crops that require multiple fungicide applications and that are impacted by the development of resistance.
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14
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Patocchi A, Wehrli A, Dubuis PH, Auwerkerken A, Leida C, Cipriani G, Passey T, Staples M, Didelot F, Philion V, Peil A, Laszakovits H, Rühmer T, Boeck K, Baniulis D, Strasser K, Vávra R, Guerra W, Masny S, Ruess F, Le Berre F, Nybom H, Tartarini S, Spornberger A, Pikunova A, Bus VGM. Ten Years of VINQUEST: First Insight for Breeding New Apple Cultivars With Durable Apple Scab Resistance. Plant Dis 2020; 104:2074-2081. [PMID: 32525450 DOI: 10.1094/pdis-11-19-2473-sr] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Apple scab, caused by Venturia inaequalis, is a major fungal disease worldwide. Cultivation of scab-resistant cultivars would reduce the chemical footprint of apple production. However, new apple cultivars carrying durable resistances should be developed to prevent or at least slow the breakdown of resistance against races of V. inaequalis. One way to achieve durable resistance is to pyramid multiple scab resistance genes in a cultivar. The choice of the resistance genes to be combined in the pyramids should take into account the frequency of resistance breakdown and the geographical distribution of apple scab isolates able to cause such breakdowns. In order to acquire this information and to make it available to apple breeders, the VINQUEST project (www.vinquest.ch) was initiated in 2009. Ten years after launching this project, 24 partners from 14 countries regularly contribute data. From 2009 to 2018, nearly 9,000 data points have been collected. This information has been used to identify the most promising apple scab resistance genes for developing cultivars with durable resistance, which to date are: Rvi5, Rvi11, Rvi12, Rvi14, and Rvi15. As expected, Rvi1, together with Rvi3 and Rvi8, were often overcome, and have little value for scab resistance breeding. Rvi10 may also belong to this group. On the other hand, Rvi2, Rvi4, Rvi6, Rvi7, Rvi9, and Rvi13 are still useful for breeding, but their use is recommended only in extended pyramids of ≥3 resistance genes.
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Affiliation(s)
| | - Andreas Wehrli
- Agroscope, Breeding Research, 8820 Wädenswil, Switzerland
| | | | | | - Carmen Leida
- Consorzio Italiano Vivaisti CIV, 44022 San Giuseppe di Comacchio, Italy
| | - Guido Cipriani
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, University of Udine, 33100 Udine, Italy
| | - Tom Passey
- NIAB EMR, East Malling, West Malling ME19 6BJ, United Kingdom
| | - Martina Staples
- Höhere Bundeslehranstalt und Bundesamt für Wein- und Obstbau Klosterneuburg, 3400 Klosterneuburg, Austria
| | - Frédérique Didelot
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, 49071 Beaucouzé, France
| | - Vincent Philion
- Institut de Recherche et de Développement en Agroenvironnement, Saint-Bruno-de-Montarville, QC J3V 0G7, Canada
| | - Andreas Peil
- Julius Kühn-Institut (JKI), Bundesforschungsinstitut für Kulturpflanzen, Institut für Züchtungsforschung an Obst, 01326 Dresden, Germany
| | | | - Thomas Rühmer
- Versuchsstation Obst- und Weinbau Haidegg, 8047 Graz, Austria
| | - Klemens Boeck
- Landwirtschaftskammer Tirol, 6020 Innsbruck, Austria
| | - Danas Baniulis
- Lithuanian Research Centre for Agriculture and Forestry, 54333 Babtai, Lithuania
| | | | - Radek Vávra
- Research and Breeding Institute of Pomology, Holovousy 129, 508 01 Horice, Czech Republic
| | - Walter Guerra
- Laimburg Research Centre, Laimburg 6, 39040 Ora, Italy
| | | | - Franz Ruess
- Staatliche Lehr- und Versuchsanstalt für Wein und Obstbau Weinsberg, 74189 Weinsberg, Germany
| | - Fanny Le Berre
- Station d'études et d'expérimentations fruitières de La Morinière, La Morinière, 37800 Saint Epain, France
| | - Hilde Nybom
- Swedish University of Agricultural Sciences, Balsgård, 29194 Kristianstad, Sweden
| | - Stefano Tartarini
- Department of Agricultural and Food Sciences, University of Bologna, 40126 Bologna, Italy
| | | | - Anna Pikunova
- VNIISPK - Russian Research Institute of Fruit Crop Breeding, 302530 Zilina, Russia
| | - Vincent G M Bus
- The New Zealand Institute for Plant and Food Research Limited, 4157 Havelock North, New Zealand
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15
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Rebel P, Poblete-Echeverría C, van Zyl JG, Wessels JPB, Coetzer C, McLeod A. Determining Mancozeb Deposition Benchmark Values on Apple Leaves for the Management of Venturia inaequalis. Plant Dis 2020; 104:168-178. [PMID: 31697224 DOI: 10.1094/pdis-04-19-0873-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Apple scab, caused by Venturia inaequalis, is the most common fruit and foliar disease in commercial apple production worldwide. Early in the production season, preventative contact fungicide sprays are essential for protecting highly susceptible continuously unfolding and expanding young leaves. In South Africa, mancozeb is a key contact fungicide used for controlling apple scab early in the season. The current study developed deposition benchmarks indicative of the biological efficacy of mancozeb against apple scab, using a laboratory-based apple seedling model system. The model system employed a yellow fluorescent pigment that is known to be an effective tracer of mancozeb deposition. A concentration range of mancozeb (0.15 to 1 times the registered dosage) and fluorescent pigment concentrations was sprayed onto seedling leaves, which yielded various fluorescent particle coverage (FPC%) levels. Modeling of the FPC% values versus percent disease control yielded different benchmark values when disease quantification was conducted using two different methods. Thermal infrared imaging (TIRI) disease quantification resulted in a benchmark model where 0.40%, 0.79%, and 1.35 FPC% yielded 50, 75, and 90% apple scab control, respectively. These FPC% values were higher than the benchmarks (0.10, 0.20, and 0.34 FPC%, respectively) obtained with quantitative real-time PCR (qPCR) disease quantification. The qPCR benchmark model is recommended as a guideline for evaluating the efficacy of mancozeb sprays on leaves in apple orchards since the TIRI benchmark model underestimated disease control. The TIRI benchmark model yielded 68% disease control at the lowest mancozeb dosage, yet no visible lesion developed at this dosage. Both benchmark models showed that mancozeb yielded high levels of disease control at very low concentrations; for the qPCR benchmark model the FPC% value of the FPC90 (90% control) corresponded to 0.15 times that of the registered mancozeb concentration in South Africa, i.e., 85% lower than the registered dosage.
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Affiliation(s)
- P Rebel
- Department of Plant Pathology, Stellenbosch University, Matieland, 7600, South Africa
| | - C Poblete-Echeverría
- Department of Viticulture and Oenology, Stellenbosch University, 7600, South Africa
| | | | | | - C Coetzer
- Department of Plant Pathology, Stellenbosch University, Matieland, 7600, South Africa
| | - A McLeod
- Department of Plant Pathology, Stellenbosch University, Matieland, 7600, South Africa
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16
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Le Cam B, Sargent D, Gouzy J, Amselem J, Bellanger MN, Bouchez O, Brown S, Caffier V, De Gracia M, Debuchy R, Duvaux L, Payen T, Sannier M, Shiller J, Collemare J, Lemaire C. Population Genome Sequencing of the Scab Fungal Species Venturia inaequalis, Venturia pirina, Venturia aucupariae and Venturia asperata. G3 (Bethesda) 2019; 9:2405-14. [PMID: 31253647 DOI: 10.1534/g3.119.400047] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The Venturia genus comprises fungal species that are pathogens on Rosaceae host plants, including V. inaequalis and V. asperata on apple, V. aucupariae on sorbus and V. pirina on pear. Although the genetic structure of V. inaequalis populations has been investigated in detail, genomic features underlying these subdivisions remain poorly understood. Here, we report whole genome sequencing of 87 Venturia strains that represent each species and each population within V. inaequalis. We present a PacBio genome assembly for the V. inaequalis EU-B04 reference isolate. The size of selected genomes was determined by flow cytometry, and varied from 45 to 93 Mb. Genome assemblies of V. inaequalis and V. aucupariae contain a high content of transposable elements (TEs), most of which belong to the Gypsy or Copia LTR superfamilies and have been inactivated by Repeat-Induced Point mutations. The reference assembly of V. inaequalis presents a mosaic structure of GC-equilibrated regions that mainly contain predicted genes and AT-rich regions, mainly composed of TEs. Six pairs of strains were identified as clones. Single-Nucleotide Polymorphism (SNP) analysis between these clones revealed a high number of SNPs that are mostly located in AT-rich regions due to misalignments and allowed determining a false discovery rate. The availability of these genome sequences is expected to stimulate genetics and population genomics research of Venturia pathogens. Especially, it will help understanding the evolutionary history of Venturia species that are pathogenic on different hosts, a history that has probably been substantially influenced by TEs.
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17
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Marolleau B, Gaucher M, Heintz C, Degrave A, Warneys R, Orain G, Lemarquand A, Brisset MN. When a Plant Resistance Inducer Leaves the Lab for the Field: Integrating ASM into Routine Apple Protection Practices. Front Plant Sci 2017; 8:1938. [PMID: 29255473 PMCID: PMC5723009 DOI: 10.3389/fpls.2017.01938] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 10/27/2017] [Indexed: 05/09/2023]
Abstract
Plant resistance inducers, also called elicitors, could be useful to reduce the use of pesticides. However, their performance in controlling diseases in the field remains unsatisfactory due to lack of specific knowledge of how they can integrate crop protection practices. In this work, we focused on apple crop and acibenzolar-S-methyl (ASM), a well-known SAR (systemic acquired resistance) inducer of numerous plant species. We provide a protocol for orchard-effective control of apple scab due to the ascomycete fungus Venturia inaequalis, by applying ASM in combination with a light integrated pest management program. Besides we pave the way for future optimization levers by demonstrating in controlled conditions (i) the high influence of apple genotypes, (ii) the ability of ASM to prime defenses in newly formed leaves, (iii) the positive effect of repeated elicitor applications, (iv) the additive effect of a thinning fruit agent.
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Affiliation(s)
- Brice Marolleau
- IRHS, INRA, Agrocampus-Ouest, Université d’Angers, SFR 4207 QUASAV, Beaucouzé, France
| | - Matthieu Gaucher
- IRHS, INRA, Agrocampus-Ouest, Université d’Angers, SFR 4207 QUASAV, Beaucouzé, France
| | - Christelle Heintz
- IRHS, INRA, Agrocampus-Ouest, Université d’Angers, SFR 4207 QUASAV, Beaucouzé, France
| | - Alexandre Degrave
- IRHS, INRA, Agrocampus-Ouest, Université d’Angers, SFR 4207 QUASAV, Beaucouzé, France
| | - Romain Warneys
- IRHS, INRA, Agrocampus-Ouest, Université d’Angers, SFR 4207 QUASAV, Beaucouzé, France
| | - Gilles Orain
- Unité Expérimentale Horticole, INRA, Beaucouzé, France
| | | | - Marie-Noëlle Brisset
- IRHS, INRA, Agrocampus-Ouest, Université d’Angers, SFR 4207 QUASAV, Beaucouzé, France
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18
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Thuerig B, Ramseyer J, Hamburger M, Oberhänsli T, Potterat O, Schärer HJ, Tamm L. Efficacy of a Juncus effusus extract on grapevine and apple plants against Plasmopara viticola and Venturia inaequalis, and identification of the major active constituent. Pest Manag Sci 2016; 72:1718-1726. [PMID: 26616740 DOI: 10.1002/ps.4199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND There is growing demand to replace chemical pesticides with alternatives owing to concerns related to impacts on human health and the environment. Plant-derived plant protection products could provide sustainable and environmentally friendly alternatives to chemical products. The aim of this study was to identify plant and fungal extracts with so far unknown activity against important plant pathogens by in vitro screening of a library of more than 3000 extracts. RESULTS Several plant extracts with promising in vitro fungicidal activity (MIC100 ≤ 50 µg mL(-1) ) towards one or several of the investigated pathogens (Venturia ineaqualis, Phytophthora infestans, Plasmopara viticola) were identified by the screening. One of the hits, an ethyl acetate extract of Juncus effusus L. medulla, was further investigated, and dehydroeffusol (DHEF) was identified as its main active constituent. On susceptible grapevine and apple seedlings, efficacies of up to 100% were reached with the extract (EC50 123 or 156 µg mL(-1) ) and with DHEF (EC50 18 or 21 µg mL(-1) ) against P. viticola and V. inaequalis respectively. CONCLUSIONS Our results demonstrate that plants can provide promising alternatives for integrated and organic farming. J. effusus shows high efficacy at low concentrations and, as an abundant perennial species, is an interesting candidate for the development of a novel plant protection product. © 2015 Society of Chemical Industry.
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Affiliation(s)
- Barbara Thuerig
- Research Institute of Organic Agriculture FiBL, Frick, Switzerland
| | - Justine Ramseyer
- Department of Pharmaceutical Biology, University of Basel, Basel, Switzerland
| | - Matthias Hamburger
- Department of Pharmaceutical Biology, University of Basel, Basel, Switzerland
| | | | - Olivier Potterat
- Department of Pharmaceutical Biology, University of Basel, Basel, Switzerland
| | | | - Lucius Tamm
- Research Institute of Organic Agriculture FiBL, Frick, Switzerland
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19
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Bastiaanse H, Bassett HCM, Kirk C, Gardiner SE, Deng C, Groenworld R, Chagné D, Bus VGM. Scab resistance in 'Geneva' apple is conditioned by a resistance gene cluster with complex genetic control. Mol Plant Pathol 2016; 17:159-72. [PMID: 25892110 PMCID: PMC6638522 DOI: 10.1111/mpp.12269] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most severe diseases of apple worldwide. It is the most studied plant-pathogen interaction involving a woody species using modern genetic, genomic, proteomic and bioinformatic approaches in both species. Although 'Geneva' apple was recognized long ago as a potential source of resistance to scab, this resistance has not been characterized previously. Differential interactions between various monoconidial isolates of V. inaequalis and six segregating F1 and F2 populations indicate the presence of at least five loci governing the resistance in 'Geneva'. The 17 chromosomes of apple were screened using genotyping-by-sequencing, as well as single marker mapping, to position loci controlling the V. inaequalis resistance on linkage group 4. Next, we fine mapped a 5-cM region containing five loci conferring both dominant and recessive scab resistance to the distal end of the linkage group. This region corresponds to 2.2 Mbp (from 20.3 to 22.5 Mbp) on the physical map of 'Golden Delicious' containing nine candidate nucleotide-binding site leucine-rich repeat (NBS-LRR) resistance genes. This study increases our understanding of the complex genetic basis of apple scab resistance conferred by 'Geneva', as well as the gene-for-gene (GfG) relationships between the effector genes in the pathogen and resistance genes in the host.
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Affiliation(s)
- Héloïse Bastiaanse
- Plant Pathology Unit, Gembloux Agro-Bio Tech, University of Liège, avenue Maréchal Juin 13, Gembloux 5030, Belgium
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), Private Bag 11600, Palmerston North 4442, New Zealand
- Plant & Food Research, Private Bag 1401, Havelock North 4157, New Zealand
| | - Heather C M Bassett
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), Private Bag 11600, Palmerston North 4442, New Zealand
| | - Christopher Kirk
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), Private Bag 11600, Palmerston North 4442, New Zealand
| | - Susan E Gardiner
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), Private Bag 11600, Palmerston North 4442, New Zealand
| | - Cecilia Deng
- Plant & Food Research, Private Bag 92169, Auckland 1142, New Zealand
| | - Remmelt Groenworld
- Plant Breeding, Wageningen University & Research, PO Box 386, 6700 AJ Wageningen, the Netherlands
| | - David Chagné
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), Private Bag 11600, Palmerston North 4442, New Zealand
| | - Vincent G M Bus
- Plant & Food Research, Private Bag 1401, Havelock North 4157, New Zealand
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Cornille A, Gladieux P, Giraud T. Crop-to-wild gene flow and spatial genetic structure in the closest wild relatives of the cultivated apple. Evol Appl 2013; 6:737-748. [PMID: 29387162 PMCID: PMC5779123 DOI: 10.1111/eva.12059] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 01/21/2013] [Indexed: 11/29/2022] Open
Abstract
Crop‐to‐wild gene flow have important evolutionary and ecological consequences and require careful consideration in conservation programs for wild genetic resources of potential use in breeding programs and in assessments of the risk of transgene escape into natural ecosystems. Using 26 microsatellites and a set of 1181 trees, we investigated the extent of introgression from the cultivated apple, Malus domestica, to its three closest wild relatives, M. sylvestris in Europe, M. orientalis in the Caucasus, and M. sieversii in Central Asia. We found footprints of introgression from M. domestica to M. orientalis (3.2% of hybrids), M. sieversii (14.8%), and M. sylvestris (36.7%). Malus sieversii and M. orientalis presented weak, but significant genetic structures across their geographic range. Malus orientalis displayed genetic differentiation with three differentiated populations in Turkey, Armenia, and Russia. Malus sieversii consisted of a main population spread over Central Asia and a smaller population in the Tian Shan Mountains. The low Sp values suggest high dispersal capacities for the wild apple relatives. High potential for crop‐to‐wild gene flow in apples needs to be considered in the implementation of in situ and ex situ actions for the conservation of wild apple genetic resources potentially useful to plant breeding.
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Affiliation(s)
- Amandine Cornille
- CNRS Laboratoire Ecologie Systématique et Evolution - UMR8079 Orsay France.,University Paris Sud Orsay France
| | - Pierre Gladieux
- CNRS Laboratoire Ecologie Systématique et Evolution - UMR8079 Orsay France.,University Paris Sud Orsay France.,Department of Plant and Microbial Biology University of CaliforniaB erkeley CA 94720-3102 USA
| | - Tatiana Giraud
- CNRS Laboratoire Ecologie Systématique et Evolution - UMR8079 Orsay France.,University Paris Sud Orsay France
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21
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Leroy T, Lemaire C, Dunemann F, Le Cam B. The genetic structure of a Venturia inaequalis population in a heterogeneous host population composed of different Malus species. BMC Evol Biol 2013; 13:64. [PMID: 23497223 PMCID: PMC3626921 DOI: 10.1186/1471-2148-13-64] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 02/26/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Adaptation, which induces differentiation between populations in relation to environmental conditions, can initiate divergence. The balance between gene flow and selection determines the maintenance of such a structure in sympatry. Studying these two antagonistic forces in plant pathogens is made possible because of the high ability of pathogens to disperse and of the strong selective pressures exerted by their hosts. In this article, we analysed the genetic structure of the population of the apple scab fungus, Venturia inaequalis, in a heterogeneous environment composed of various Malus species. Inferences were drawn from microsatellite and AFLP data obtained from 114 strains sampled in a single orchard on nine different Malus species to determine the forces that shape the genetic structure of the pathogen. RESULTS Using clustering methods, we first identified two specialist subpopulations: (i) a virulent subpopulation sampled on Malus trees carrying the Rvi6 resistance gene; and (ii) a subpopulation infecting only Malus trees that did not carry this resistance gene. A genome scan of loci on these two subpopulations did not detect any locus under selection. Additionally, we did not detect any other particular substructure linked to different hosts. However, an isolation-by-distance (IBD) pattern at the orchard scale revealed free gene flow within each subpopulation. CONCLUSIONS Our work shows a rare example of a very strong effect of a resistance gene on pathogen populations. Despite the high diversity of Malus hosts, the presence of Rvi6 seems sufficient to explain the observed genetic structure. Moreover, detection of an IBD pattern at the orchard scale revealed a very low average dispersal distance that is particularly significant for epidemiologists and landscape managers for the design of scab control strategies.
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Affiliation(s)
- Thibault Leroy
- Université d’Angers, IRHS, PRES UNAM, SFR QUASAV, Boulevard Lavoisier, Angers, 49045 France
- INRA, IRHS, PRES UNAM, SFR QUASAV, Rue Georges Morel, Beaucouzé, 49071 France
- Agrocampus Ouest, IRHS, PRES UNAM, SFR QUASAV, Rue Le Nôtre, F-49045 Angers, France
| | - Christophe Lemaire
- Université d’Angers, IRHS, PRES UNAM, SFR QUASAV, Boulevard Lavoisier, Angers, 49045 France
- INRA, IRHS, PRES UNAM, SFR QUASAV, Rue Georges Morel, Beaucouzé, 49071 France
- Agrocampus Ouest, IRHS, PRES UNAM, SFR QUASAV, Rue Le Nôtre, F-49045 Angers, France
| | - Frank Dunemann
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Horticultural and Fruit Crops, Erwin-Baur-Strasse 27, 06484, Quedlinburg, Germany
| | - Bruno Le Cam
- Université d’Angers, IRHS, PRES UNAM, SFR QUASAV, Boulevard Lavoisier, Angers, 49045 France
- INRA, IRHS, PRES UNAM, SFR QUASAV, Rue Georges Morel, Beaucouzé, 49071 France
- Agrocampus Ouest, IRHS, PRES UNAM, SFR QUASAV, Rue Le Nôtre, F-49045 Angers, France
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Lê Van A, Gladieux P, Lemaire C, Cornille A, Giraud T, Durel CE, Caffier V, Le Cam B. Evolution of pathogenicity traits in the apple scab fungal pathogen in response to the domestication of its host. Evol Appl 2012; 5:694-704. [PMID: 23144656 PMCID: PMC3492895 DOI: 10.1111/j.1752-4571.2012.00246.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 01/09/2012] [Indexed: 02/04/2023] Open
Abstract
Understanding how pathogens emerge is essential to bring disease-causing agents under durable human control. Here, we used cross-pathogenicity tests to investigate the changes in life-history traits of the fungal pathogen Venturia inaequalis associated with host-tracking during the domestication of apple and subsequent host-range expansion on the wild European crabapple (Malus sylvestris). Pathogenicity of 40 isolates collected in wild and domesticated ecosystems was assessed on the domesticated apple, its Central Asian main progenitor (M. sieversii) and M. sylvestris. Isolates from wild habitats in the centre of origin of the crop were not pathogenic on the domesticated apple and less aggressive than other isolates on their host of origin. Isolates from the agro-ecosystem in Central Asia infected a higher proportion of plants with higher aggressiveness, on both the domesticated host and its progenitor. Isolates from the European crabapple were still able to cause disease on other species but were less aggressive and less frequently virulent on these hosts than their endemic populations. Our results suggest that the domestication of apple was associated with the acquisition of virulence in the pathogen following host-tracking. The spread of the disease in the agro-ecosystem would also have been accompanied by an increase in overall pathogenicity.
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Affiliation(s)
- Amandine Lê Van
- INRA, UMR1345, IRHS (INRA, Agrocampus-Ouest, Université d'Angers) SFR QUASAV, Beaucouzé, France
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Sutton DK, MacHardy WE, Lord WG. Effects of Shredding or Treating Apple Leaf Litter with Urea on Ascospore Dose of Venturia inaequalis and Disease Buildup. Plant Dis 2000; 84:1319-1326. [PMID: 30831875 DOI: 10.1094/pdis.2000.84.12.1319] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ascospores produced on diseased leaves in the leaf litter constitute the primary inoculum causing scab in commercial apple orchards in the northeastern United States. Two sanitation practices, shredding the leaf litter with a flail mower and urea application, were evaluated for their potential to reduce the risk of primary scab. Three measures of a treatment's potential were made: leaf litter density was evaluated to determine reduction of the source or primary inoculum; trapped ascospores were counted to measure the reduction of primary inoculum; and scab lesions on trees and seedlings were counted to determine reduction in disease incidence and severity on leaves and fruit. The results show that in the northeastern United States, shredding the leaf litter in November or April will reduce the risk of scab by 80 to 90% if all of the leaf litter is shredded. If 10 to 35% of the leaf litter cannot be shredded because of the limited offset of the flail mower and spread of the tree canopy, then the risk of scab is reduced by 50 to 65%. Urea applied to the leaf litter in November (when approximately 95% of the leaves had fallen) reduced the number of ascospores trapped by 50%. Urea applied to the leaf litter in April (before bud break) reduced the number of ascospores trapped by 66%. The reductions are discussed in relation to a sanitation action threshold that links sanitation to a strategy that reduces the fungicide dose to control primary scab in an orchard assessed with a moderate amount of foliar scab the previous autumn.
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Affiliation(s)
| | | | - William G Lord
- Extension Fruit Specialist, Department of Plant Biology, Spaulding Hall, University of New Hampshire, Durham 03824
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