1
|
Rad SH, Ebrahimi L, Croll D. Virulence Associations and Global Context of AvrStb6 Genetic Diversity in Iranian Populations of Zymoseptoria tritici. PHYTOPATHOLOGY 2023; 113:1924-1933. [PMID: 37261424 DOI: 10.1094/phyto-09-22-0348-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Managing pathogen damage in wheat production is important for sustaining yields. Fungal plant pathogen genomes encode many small secreted proteins acting as effectors that play key roles in the successful colonization of host tissue and triggering host defenses. AvrStb6 is the first described Zymoseptoria tritici avirulence effector, which triggers Stb6-mediated immunity in the wheat host in a gene-for-gene manner. Evasion of major resistance factors such as Stb6 challenges deployment decisions on wheat cultivars. In this study, we analyzed the evolution of the AvrStb6 effector in Iranian isolates of Z. tritici. In total, 78 isolates were isolated and purified from 30 infected wheat specimens collected from the East Azerbaijan and Ardabil provinces of Iran. The pathogenicity of all isolates was evaluated on the susceptible wheat cultivar 'Tajan'. A subset of 40 isolates were also tested for pathogenicity on the resistant cultivar 'Shafir' carrying Stb6. Genetic diversity at the AvrStb6 locus was analyzed for 14 isolates covering the breadth of the observed disease severity. The AvrStb6 sequence variation was high, with virulent isolates carrying highly diverse AvrStb6 haplotypes. In an analysis including more than 1,000 additional AvrStb6 sequences from a global set of isolates, we found that virulent isolates carried AvrStb6 haplotypes either clustering with known virulent haplotypes on different continents or constituting previously unknown haplotypes. Furthermore, we found that AvrStb6 variants from avirulent isolates clustered with known avirulent genotypes from Europe. Our study highlights the relevance of AvrStb6 for Z. tritici virulence and the exceptional global diversity patterns of this effector.
Collapse
Affiliation(s)
- Sepideh Hatami Rad
- Department of Entomology and Plant Pathology, College of Agricultural Technology, University College of Agriculture and Natural Resources, University of Tehran, Tehran 33916-53755, Iran
| | - Leila Ebrahimi
- Department of Entomology and Plant Pathology, College of Agricultural Technology, University College of Agriculture and Natural Resources, University of Tehran, Tehran 33916-53755, Iran
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchatel, CH-2000 Neuchatel, Switzerland
| |
Collapse
|
2
|
Standish JR, Brenneman TB, Bock CH, Stevenson KL. Spatial Variation and Temporal Dynamics of Fungicide Sensitivity in Venturia effusa Within a Pecan Orchard. PLANT DISEASE 2021; 105:377-383. [PMID: 32729799 DOI: 10.1094/pdis-04-20-0889-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
An 18-ha commercial pecan orchard was sampled over 3 years to study the spatial and temporal variation in fungicide sensitivity of Venturia effusa, cause of pecan scab. The orchard was divided into a two-dimensional, 8 × 8 grid of 64 quadrats, each containing nine trees (unless there were missing trees), and samples were collected once per year from each quadrat to be tested for sensitivity to fentin hydroxide, propiconazole, and thiophanate-methyl. Averaged across the orchard, insensitivity to all three fungicides was significantly lower in 2016 compared with 2015, but significantly greater for fentin hydroxide and thiophanate-methyl in 2017. Although significant spatial autocorrelation was observed for sensitivity to propiconazole in 2017 and for thiophanate-methyl in 2015 and 2017, indicating clustering, all other fungicide-by-year combinations were not significant. Omnidirectional spatial dependence was observed for sensitivity to propiconazole and thiophanate-methyl in 2017. In both instances, the semivariance increased linearly with lag distance; however, the range of spatial dependence was >276.5 m and could not be estimated accurately. Additionally, a separate sampling was conducted in all 3 years to identify an appropriate sampling size and pattern for fungicide sensitivity screening. A leaflet sample size of 165 in 11 groups of 15 allowed for accurate sensitivity testing for the three fungicides in all 3 years; however, a sample size of 45 leaflets in three groups of 15 was sufficient for quantifying sensitivity for propiconazole and thiophanate-methyl, in most cases. These results indicate that considerable biological variation in fungicide sensitivity exists in orchard-scale populations of V. effusa and that the spatial characteristics of those populations may differ in two-dimensional space depending on the growing season.
Collapse
Affiliation(s)
- J R Standish
- Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton, GA 31793
| | - T B Brenneman
- Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton, GA 31793
| | - C H Bock
- U.S. Department of Agriculture Agricultural Research Service, Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008
| | - K L Stevenson
- Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton, GA 31793
| |
Collapse
|
3
|
Hagerty CH, Klein AM, Reardon CL, Kroese DR, Melle CJ, Graber KR, Mundt CC. Baseline and Temporal Changes in Sensitivity of Zymoseptoria tritici Isolates to Benzovindiflupyr in Oregon, U.S.A., and Cross-Sensitivity to Other SDHI Fungicides. PLANT DISEASE 2021; 105:169-174. [PMID: 33170771 DOI: 10.1094/pdis-10-19-2125-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Zymoseptoria tritici is the causal agent of Septoria tritici blotch (STB), a disease of wheat (Triticum aestivum) that results in significant yield loss worldwide. Z. tritici's life cycle, reproductive system, effective population size, and gene flow put it at high likelihood of developing fungicide resistance. Succinate dehydrogenase inhibitor (SDHI) fungicides (FRAC code 7) were not widely used to control STB in the Willamette Valley until 2016. Field isolates of Z. tritici collected in the Willamette Valley at dates spanning the introduction of SDHI (2015 to 2017) were screened for sensitivity to four SDHI active ingredients: benzovindiflupyr, penthiopyrad, fluxapyroxad, and fluindapyr. Fungicide sensitivity changes were determined by the fungicide concentration at which fungal growth is decreased by 50% (EC50) values. The benzovindiflupyr EC50 values increased significantly, indicating a reduction in sensitivity, following the adoption of SDHI fungicides in Oregon (P < 0.0001). Additionally, significant reduction in cross-sensitivity among SDHI active ingredients was also observed with a moderate and significant relationship between penthiopyrad and benzovindiflupyr (P = 0.0002) and a weak relationship between penthiopyrad and fluxapyroxad (P = 0.0482). No change in cross-sensitivity was observed with fluindapyr, which has not yet been labeled in the region. The results document a decrease in SDHI sensitivity in Z. tritici isolates following the introduction of the active ingredients to the Willamette Valley. The reduction in cross-sensitivity observed between SDHI active ingredients highlights the notion that careful consideration is required to manage fungicide resistance and suggests that within-group rotation is insufficient for resistance management.
Collapse
Affiliation(s)
- Christina H Hagerty
- Columbia Basin Agricultural Research Center, Oregon State University, Adams, OR 97810
| | - Ann M Klein
- Columbia Basin Agricultural Research Center, Oregon State University, Adams, OR 97810
| | - Catherine L Reardon
- Soil and Water Conservation Unit, United States Department of Agriculture-Agricultural Research Service, Adams, OR 97810
| | - Duncan R Kroese
- Columbia Basin Agricultural Research Center, Oregon State University, Adams, OR 97810
| | - Caroline J Melle
- Soil and Water Conservation Unit, United States Department of Agriculture-Agricultural Research Service, Adams, OR 97810
| | - Kaci R Graber
- Columbia Basin Agricultural Research Center, Oregon State University, Adams, OR 97810
| | - Christopher C Mundt
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97330
| |
Collapse
|
4
|
Yu X, Zhu X, Zhou Y, Li Q, Hu Z, Li T, Tao J, Dou M, Zhang M, Shao Y, Sun R. Discovery of N-Aryl-pyridine-4-ones as Novel Potential Agrochemical Fungicides and Bactericides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:13904-13913. [PMID: 31765135 DOI: 10.1021/acs.jafc.9b06296] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A series of N-aryl-pyridine-4-one derivatives were designed and synthesized using maltol and antidesmone as lead compounds, and then their fungicidal/bactericidal activities and possible mechanism of action against Colletotrichum musae were explored. Most of these compounds exhibited significant fungicidal activity in vitro. Especially, compound 23 has more than 90% inhibitory activity against nine plant pathogenic fungi at 50 μg mL-1, which is superior to azoxystrobin. Moreover, an in vivo bioassay also demonstrated that compound 23 exhibited high-efficiency broad-spectrum antifungal activity and can effectively control postharvest diseases of mango. In addition, it was found that compounds 22 and 23 can also effectively control rice bacterial leaf blight in pot experiments, which was even more effective than zhongshengmycin. Preliminary mechanism studies revealed that compound 23 may cause cell membrane and mitochondria destruction. These findings indicate that compound 23 can be used to develop potential agrochemical fungicides and bactericides.
Collapse
Affiliation(s)
- Xiuqiang Yu
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Xinyue Zhu
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Yang Zhou
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Qinglin Li
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Zhan Hu
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Ting Li
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources , Haikou , Hainan 570228 , People's Republic of China
| | - Jun Tao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources , Haikou , Hainan 570228 , People's Republic of China
| | - Menglan Dou
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Meng Zhang
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Yu Shao
- Danzhou Tobacco Company , Hainan Provincial Branch of China National Tobacco Corporation (CNTC) , Danzhou , Hainan 571700 , People's Republic of China
| | - Ranfeng Sun
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| |
Collapse
|
5
|
Garnault M, Duplaix C, Leroux P, Couleaud G, Carpentier F, David O, Walker AS. Spatiotemporal dynamics of fungicide resistance in the wheat pathogen Zymoseptoria tritici in France. PEST MANAGEMENT SCIENCE 2019; 75:1794-1807. [PMID: 30680908 DOI: 10.1002/ps.5360] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/16/2018] [Accepted: 01/09/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Management of pesticide resistance is a major issue in modern agricultural systems, particularly in the context of the broader challenge of reducing pesticide use. However, such management must be adapted to resistance dynamics, which remains challenging to predict due to its dependence on many biological traits of pests, interactions with the environment and pesticide use. We retrospectively studied the evolution of reported resistances to four modes of action (benzimidazoles, quinone outside inhibitors, sterol demethylation inhibitors and succinate dehydrogenase inhibitors), in French populations of the wheat pathogen Zymoseptoria tritici. RESULTS We used statistical models to analyse the Performance trial network data set (2004-2017; ∼ 70 locations in France yearly). They highlighted contrasting behaviours between phenotypes, for example: (i) stable spatial distributions and colonization front structures over time, and (ii) different frequency growth rates at the national scale and between regions. CONCLUSION We provide a quantitative description of the spatiotemporal patterns of resistance evolution for fungicides with several modes of action. Moreover, we highlight some unexpected resistance dynamics in France, with major differences between the north and south. This complex pattern of resistance evolution in French populations is consistent with previous descriptions of dynamics at the European scale. These results should make it easier to anticipate evolution locally and to improve the management of resistance. © 2019 Society of Chemical Industry.
Collapse
Affiliation(s)
- Maxime Garnault
- UMR1290 BIOGER, INRA, AgroParisTech, Université Paris-Saclary, Thiverval-Grignon, France
- MaIAGE, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Clémentine Duplaix
- UMR1290 BIOGER, INRA, AgroParisTech, Université Paris-Saclary, Thiverval-Grignon, France
| | - Pierre Leroux
- UMR1290 BIOGER, INRA, AgroParisTech, Université Paris-Saclary, Thiverval-Grignon, France
| | | | - Florence Carpentier
- UMR1290 BIOGER, INRA, AgroParisTech, Université Paris-Saclary, Thiverval-Grignon, France
- MaIAGE, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Olivier David
- MaIAGE, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Anne-Sophie Walker
- UMR1290 BIOGER, INRA, AgroParisTech, Université Paris-Saclary, Thiverval-Grignon, France
| |
Collapse
|
6
|
Rapid Parallel Evolution of Azole Fungicide Resistance in Australian Populations of the Wheat Pathogen Zymoseptoria tritici. Appl Environ Microbiol 2019; 85:AEM.01908-18. [PMID: 30530713 DOI: 10.1128/aem.01908-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/30/2018] [Indexed: 11/20/2022] Open
Abstract
Zymoseptoria tritici is a globally distributed fungal pathogen which causes Septoria tritici blotch on wheat. Management of the disease is attempted through the deployment of resistant wheat cultivars and the application of fungicides. However, fungicide resistance is commonly observed in Z. tritici populations, and continuous monitoring is required to detect breakdowns in fungicide efficacy. We recently reported azole-resistant isolates in Australia; however, it remained unknown whether resistance was brought into the continent through gene flow or whether resistance emerged independently. To address this question, we screened 43 isolates across five Australian locations for azole sensitivity and performed whole-genome sequencing on 58 isolates from seven locations to determine the genetic basis of resistance. Population genomic analyses showed extremely strong differentiation between the Australian population recovered after azoles began to be used and both Australian populations recovered before azoles began to be used and populations on different continents. The apparent absence of recent gene flow between Australia and other continents suggests that azole fungicide resistance has evolved de novo and subsequently spread within Tasmania. Despite the isolates being distinct at the whole-genome level, we observed combinations of nonsynonymous substitutions at the CYP51 locus identical to those observed elsewhere in the world. We observed nine previously reported nonsynonymous mutations as well as isolates that carried a combination of the previously reported L50S, S188N, A379G, I381V, Y459DEL, G460DEL, and N513K substitutions. Assays for the 50% effective concentration against a subset of isolates exposed to the tebuconazole and epoxiconazole fungicides showed high levels of azole resistance. The rapid, parallel evolution of a complex CYP51 haplotype that matches a dominant European haplotype demonstrates the enormous potential for de novo resistance emergence in pathogenic fungi.IMPORTANCE Fungicides are essential to control diseases in agriculture because many crops are highly susceptible to pathogens. However, many pathogens rapidly evolve resistance to fungicides. A large body of studies have described specific mutations conferring resistance and have often made inferences about the origins of resistance based on sequencing data from the target gene alone. Here, we show the de novo acquisition of resistance to the ubiquitously used azole fungicides in genetically isolated populations of the wheat pathogen Zymoseptoria tritici in Tasmania, Australia. We confirm evidence for parallel evolution through genome-scale analyses of representative worldwide populations. The emergence of complex resistance haplotypes following a well-documented recent introduction of azoles into Australian farming practices demonstrates how rapidly chemical resistance evolves in agricultural ecosystems.
Collapse
|
7
|
Hawkins NJ, Fraaije BA. Fitness Penalties in the Evolution of Fungicide Resistance. ANNUAL REVIEW OF PHYTOPATHOLOGY 2018; 56:339-360. [PMID: 29958074 DOI: 10.1146/annurev-phyto-080417-050012] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The evolution of resistance poses an ongoing threat to crop protection. Fungicide resistance provides a selective advantage under fungicide selection, but resistance-conferring mutations may also result in fitness penalties, resulting in an evolutionary trade-off. These penalties may result from the functional constraints of an evolving target site or from the resource allocation costs of overexpression or active transport. The extent to which such fitness penalties are present has important implications for resistance management strategies, determining whether resistance persists or declines between treatments, and for resistance risk assessments for new modes of action. Experimental results have proven variable, depending on factors such as temperature, nutrient status, osmotic or oxidative stress, and pathogen life-cycle stage. Functional genetics tools allow pathogen genetic background to be controlled, but this in turn raises the question of epistatic interactions. Combining fitness penalties under various conditions into a field-realistic scenario poses an important future challenge.
Collapse
Affiliation(s)
- N J Hawkins
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom;
| | - B A Fraaije
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom;
| |
Collapse
|