Molecular Phylogenetic Relationships, Trichothecene Chemotype Diversity and Aggressiveness of Strains in a Global Collection of Fusarium graminearum Species

Fusarium head blight (FHB), caused principally by the species belonging to the Fusarium graminearum species complex (FGSC), is an important disease in wheat, barley, and other small grain crops worldwide. Grain infected with species in the FGSC may be contaminated with trichothecene mycotoxins such as deoxynivalenol (DON) and nivalenol (NIV). In this study, we characterized the phylogenetic relationships, chemotype diversity, phenotypic characters, and aggressiveness of 150 strains in FGSC collected from eight different countries. Phylogenetic analysis based on portions of translation elongation factor 1-α (EF-1α) gene from 150 strains revealed six species in the FGSC, F. graminearum s.s, F. asiaticum, F. meridionale, F. cortaderiae, F. boothii, and F. austroamericanum. In this collection, 50% of the strains were 15-acetyldeoxynivalenol (15-ADON), 35% were 3-acetyldeoxynivalenol (3-ADON) and 15% were NIV. Evaluation of strains on moderately resistant (MR) wheat cultivar Carberry indicated that there is no significant difference among the species for FHB disease severity (DS), fusarium damaged kernel percentage (FDK%) and DON production. However, significant differences were observed among the chemotypes. Results showed significantly higher FHB DS, FDK%, DON production, growth rates, and macroconidia production for the 3-ADON strains than the 15-ADON and NIV strains. In addition, significant differences for FHB response variables were observed among the strains from different countries. Our results demonstrate that type and amount of trichothecene produced by a strain play a key role in determining the level of aggressiveness of that particular strain, regardless of the species.

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Activity of Demethylation Inhibitor Fungicide Metconazole on Chinese Fusarium graminearum Species Complex and Its Application in Carbendazim-Resistance Management of Fusarium Head Blight in Wheat

Plant Disease ◽

10.1094/pdis-09-18-1592-re ◽

2019 ◽

Vol 103 (5) ◽

pp. 929-937 ◽

Cited By ~ 10

Author(s):

Yabing Duan ◽

Xian Tao ◽

Huahua Zhao ◽

Xuemei Xiao ◽

Meixia Li ◽

...

Keyword(s):

Fusarium Head Blight ◽

Fusarium Graminearum ◽

Mycelial Growth ◽

Species Complex ◽

Resistance Management ◽

Head Blight ◽

Grain Yields ◽

Significant Difference ◽

Fusarium Graminearum Species Complex ◽

Demethylation Inhibitor

Fusarium graminearum species complex (FGSC), causing Fusarium head blight (FHB) of wheat, has species-specific geographical distributions in wheat-growing regions. In recent years, benzimidazole resistance of FHB pathogens has been largely widespread in China. Although the demethylation inhibitor fungicide metconazole has been used for FHB control in some countries, no information about metconazole sensitivity of Chinese FHB pathogen populations and efficacy of metconazole in FHB control in China is available. In this study, the sensitivity of FGSC to metconazole was measured with 32 carbendazim-sensitive strains and 35 carbendazim-resistant strains based on mycelial growth. The 50% effective concentration values of 67 strains were normally distributed and ranged from 0.0209 to 0.0838 μg ml−1, with a mean of 0.0481 ± 0.0134 μg ml−1. No significant difference in metconazole sensitivity was observed between carbendazim-sensitive and -resistant populations. An interactive effect of metconazole and phenamacril, a novel cyanoacrilate fungicide approved in China against Fusarium spp., in inhibiting mycelial growth showed an additive interaction at different ratios. Furthermore, field trials to evaluate the effect of metconazole and metconazole + phenamacril treatments in FHB control, deoxynivalenol (DON) production, and grain yields were performed. Compared with the fungicides carbendazim and phenamacril currently used in China, metconazole exhibits a better efficacy for FHB control, DON production, and grain yields, and dramatically reduces use dosages of chemical compounds in the field. The mixture of metconazole and phenamacril at ratios of 2:3 and 1:2 showed the greatest efficacy for FHB control, DON production, and grain yields among all the fungicide treatments but its use dosages were higher in comparison with metconazole alone. In addition, FHB control, grain yields, and DON levels were significantly correlated with each other, showing that visual disease indices can be used as an indicator of grain yields and DON contamination. Meanwhile, the frequency of carbendazim-resistant alleles in F. graminearum populations was dramatically reduced after metconazole and phenamacril alone and the mixture of metconazole and phenamacril applications, indicating that metconazole and a mixture of metconazole and phenamacril can be used for carbendazim resistance management of FHB in wheat. Overall, the findings of this study provide important data for resistance management of FHB and reducing DON contamination in wheat grains.

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Fitness traits of deoxynivalenol and nivalenol-producing Fusarium graminearum species complex strains from wheat

10.1101/235895 ◽

2017 ◽

Author(s):

C.P. Nicolli ◽

F.J. Machado ◽

P. Spolti ◽

E.M. Del Ponte

Keyword(s):

Fusarium Graminearum ◽

Mycelial Growth ◽

Species Complex ◽

Head Blight ◽

Fitness Traits ◽

Fusarium Graminearum Species Complex ◽

Important Trait ◽

South Of Brazil ◽

Species Specific ◽

Moderately Resistant

AbstractFusarium graminearum of the 15-acetyl(A)deoxynivalenol(D0N) chemotype is the main cause of Fusarium head blight (FHB) of wheat in south of Brazil. However, 3-ADON and nivalenol(NIV) chemotypes have been found in other members of the species complex causing FHB in wheat. To improve our understanding of the pathogen ecology, we assessed a range of fitness-related traits in a sample of 30 strains representatives of 15-ADON (F. graminearum), 3-ADON (F. cortaderiae and F. austroamericanum) and NIV (F. meridionale and F. cortaderiae). These included: perithecia formation on three cereal-based substrates, mycelial growth at two suboptimal temperatures, sporulation and germination, pathogenicity towards a susceptible and a moderately resistant cultivar and sensitivity to tebuconazole. The most important trait favoring F. graminearum was its 2x higher sexual fertility (> 40% PPI = perithecia production index) than the other species (< 30% PPI); PPI varied among substrates (maize > rice > wheat). In addition, sensitivity to tebuconazole appeared lower in F. graminearum which had the only strain with EC50 > 1 ppm. In the pathogenicity assays, the DON-producers were generally more aggressive (1.5 to 2x higher final severity) towards the two cultivars, with 3-ADON or 15-ADON leading to higher area under the severity curve than the NIV strains in the susceptible and moderately resistant cv., respectively. There was significant variation among strains of a same species with regards asexual fertility (mycelial growth, macroconidia production and germination), which suggest a strain-rather than a species-specific differences. These results contribute new knowledge to improve our understanding of the pathogen-related traits that may explain the dominance of certain members of the species complex in specific wheat agroecosystems.

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Fitness Traits of Deoxynivalenol and Nivalenol-Producing Fusarium graminearum Species Complex Strains from Wheat

Plant Disease ◽

10.1094/pdis-12-17-1943-re ◽

2018 ◽

Vol 102 (7) ◽

pp. 1341-1347 ◽

Cited By ~ 5

Author(s):

Camila Primieri Nicolli ◽

Franklin Jackson Machado ◽

Piérri Spolti ◽

Emerson M. Del Ponte

Keyword(s):

Fusarium Graminearum ◽

Mycelial Growth ◽

Species Complex ◽

Specific Difference ◽

Head Blight ◽

Fitness Traits ◽

Fusarium Graminearum Species Complex ◽

Important Trait ◽

Species Specific ◽

Moderately Resistant

Fusarium graminearum of the 15-acetyl-deoxynivalenol (15-ADON) chemotype is the main cause of Fusarium head blight (FHB) of wheat in southern Brazil. However, 3-ADON and nivalenol (NIV) chemotypes have been found in other members of the species complex causing FHB in wheat. To improve our understanding of the pathogen biology and ecology, we assessed a range of fitness-related traits in a sample of 30 strains representatives of 15-ADON (F. graminearum), 3-ADON (F. cortaderiae and F. austroamericanum), and NIV (F. meridionale and F. cortaderiae). These included perithecia formation on three cereal-based substrates, mycelial growth at two suboptimal temperatures, sporulation and germination, pathogenicity toward a susceptible and a moderately resistant cultivar, and sensitivity to tebuconazole. The most important trait favoring F. graminearum was a two times higher sexual fertility (>40% perithecial production index [PPI]) than the other species (<30% PPI); PPI varied among substrates (maize > rice > wheat). In addition, sensitivity to tebuconazole appeared lower in F. graminearum, which had the only strain with effective fungicide concentration to reduce 50% of mycelial growth >1 ppm. In the pathogenicity assays, the deoxynivalenol producers were generally more aggressive (1.5 to 2× higher final severity) toward the two cultivars, with 3-ADON or 15-ADON leading to higher area under the severity curve than the NIV strains in the susceptible and moderately resistant cultivars, respectively. There was significant variation among strains of the same species with regards asexual fertility (mycelial growth, macroconidia production, and germination), which suggested a strain- rather than a species-specific difference. These results contribute new knowledge to improve our understanding of the pathogen-related traits that may explain the dominance of certain members of the species complex in specific wheat agroecosystems.

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Molecular Phylogenetic Diversity and Biological Characterization of Diaporthe Species Associated with Leaf Spots of Camellia sinensis in Taiwan

Plants ◽

10.3390/plants10071434 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1434

Author(s):

Hiran A. Ariyawansa ◽

Ichen Tsai ◽

Jian-Yuan Wang ◽

Patchareeya Withee ◽

Medsaii Tanjira ◽

...

Keyword(s):

Camellia Sinensis ◽

Leaf Spot ◽

Phylogenetic Trees ◽

Fungal Infections ◽

Elongation Factor ◽

Fungal Species ◽

Tea Leaves ◽

Phenotypic Characters ◽

Leaf Spots ◽

Molecular Phylogenetic

Camellia sinensis is one of the major crops grown in Taiwan and has been widely cultivated around the island. Tea leaves are prone to various fungal infections, and leaf spot is considered one of the major diseases in Taiwan tea fields. As part of a survey on fungal species causing leaf spots on tea leaves in Taiwan, 19 fungal strains morphologically similar to the genus Diaporthe were collected. ITS (internal transcribed spacer), tef1-α (translation elongation factor 1-α), tub2 (beta-tubulin), and cal (calmodulin) gene regions were used to construct phylogenetic trees and determine the evolutionary relationships among the collected strains. In total, six Diaporthe species, including one new species, Diaporthe hsinchuensis, were identified as linked with leaf spot of C. sinensis in Taiwan based on both phenotypic characters and phylogeny. These species were further characterized in terms of their pathogenicity, temperature, and pH requirements under laboratory conditions. Diaporthe tulliensis, D. passiflorae, and D. perseae were isolated from C. sinensis for the first time. Furthermore, pathogenicity tests revealed that, with wound inoculation, only D. hongkongensis was pathogenic on tea leaves. This investigation delivers the first assessment of Diaporthe taxa related to leaf spots on tea in Taiwan.

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A Natural Mutation Involving both Pathogenicity and Perithecium Formation in the Fusarium graminearum Species Complex

G3 Genes|Genome|Genetics ◽

10.1534/g3.116.033951 ◽

2016 ◽

Vol 6 (12) ◽

pp. 3883-3892 ◽

Cited By ~ 3

Author(s):

Haruhisha Suga ◽

Koji Kageyama ◽

Masafumi Shimizu ◽

Misturo Hyakumachi

Keyword(s):

Mutant Strain ◽

Fusarium Graminearum ◽

Type Strain ◽

Species Complex ◽

Wild Type Strain ◽

Genetic Locus ◽

Chromosome 2 ◽

Wild Type ◽

Head Blight ◽

Fusarium Graminearum Species Complex

Abstract Members of the Fusarium graminearum species complex (Fg complex or FGSC) are the primary pathogens causing Fusarium head blight in wheat and barley worldwide. A natural pathogenicity mutant (strain 0225022) was found in a sample of the Fg complex collected in Japan. The mutant strain did not induce symptoms in wheat spikes beyond the point of inoculation, and did not form perithecia. No segregation of phenotypic deficiencies occurred in the progenies of a cross between the mutant and a fully pathogenic wild-type strain, which suggested that a single genetic locus controlled both traits. The locus was mapped to chromosome 2 by using sequence-tagged markers; and a deletion of ∼3 kb was detected in the mapped region of the mutant strain. The wild-type strain contains the FGSG_02810 gene, encoding a putative glycosylphosphatidylinositol anchor protein, in this region. The contribution of FGSG_02810 to pathogenicity and perithecium formation was confirmed by complementation in the mutant strain using gene transfer, and by gene disruption in the wild-type strain.

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Characterization of QTL and eQTL controlling early Fusarium graminearum infection and deoxynivalenol levels in a Wuhan 1 x Nyubai doubled haploid wheat population

BMC Plant Biology ◽

10.1186/s12870-019-2149-4 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 2

Author(s):

François Fauteux ◽

Yunli Wang ◽

Hélène Rocheleau ◽

Ziying Liu ◽

Youlian Pan ◽

...

Keyword(s):

Fusarium Graminearum ◽

Doubled Haploid ◽

Expression Patterns ◽

Doubled Haploid Population ◽

Post Inoculation ◽

Head Blight ◽

Wheat Genotypes ◽

Wheat Population ◽

Fhb Resistance ◽

Moderately Resistant

Abstract Background Fusarium head blight (FHB) is a major disease of cereal crops, caused by the fungal pathogen Fusarium graminearum and related species. Breeding wheat for FHB resistance contributes to increase yields and grain quality and to reduce the use of fungicides. The identification of genes and markers for FHB resistance in different wheat genotypes has nevertheless proven challenging. Results In this study, early infection by F. graminearum was analyzed in a doubled haploid population derived from the cross of the moderately resistant wheat genotypes Wuhan 1 and Nyubai. Three quantitative trait loci (QTL) were identified: 1AL was associated with lower deoxynivalenol content, and 4BS and 5A were associated with reduced F. graminearum infection at 2 days post inoculation. Early resistance alleles were inherited from Wuhan 1 for QTL 1AL and 4BS and inherited from Nyubai for the 5A QTL. Cis and trans expression QTL (eQTL) were identified using RNA-seq data from infected head samples. Hotspots for trans eQTL were identified in the vicinity of the 1AL and 4BS QTL peaks. Among differentially expressed genes with cis eQTL within the QTL support intervals, nine genes had higher expression associated with FHB early resistance, and four genes had higher expression associated with FHB early susceptibility. Conclusions Our analysis of genotype and gene expression data of wheat infected by F. graminearum identified three QTL associated with FHB early resistance, and linked genes with eQTL and differential expression patterns to those QTL. These findings may have applications in breeding wheat for early resistance to FHB.

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Climate change impacts on the ecology of Fusarium graminearum species complex and susceptibility of wheat to Fusarium head blight: a review

World Mycotoxin Journal ◽

10.3920/wmj2016.2053 ◽

2016 ◽

Vol 9 (5) ◽

pp. 685-700 ◽

Cited By ~ 31

Author(s):

M. Vaughan ◽

D. Backhouse ◽

E.M. Del Ponte

Keyword(s):

Climate Change ◽

Fusarium Head Blight ◽

Fusarium Graminearum ◽

Species Complex ◽

Animal Health ◽

Carbon Dioxide Concentration ◽

Host Susceptibility ◽

Head Blight ◽

Fusarium Graminearum Species Complex ◽

The Impact

Fusarium head blight (FHB) of wheat, caused mainly by a few members of the Fusarium graminearum species complex (FGSC), is a major threat to agricultural grain production, food safety, and animal health. The severity of disease epidemics and accumulation of associated trichothecene mycotoxins in wheat kernels is strongly driven by meteorological factors. The potential impacts of change in climate are reviewed from the perspective of the FGSC life cycle and host resistance mechanisms influenced by abiotic pressures at the ecological, physiological and molecular level. Alterations in climate patterns and cropping systems may affect the distribution, composition and load of FGSC inoculum, but quantitative information is lacking regarding the differential responses among FGSC members. In general, the coincidence of wet and warm environment during flowering enhances the risk of FHB epidemics, but the magnitude and direction of the change in FHB and mycotoxin risk will be a consequence of a multitude of effects on key processes affecting inoculum dynamics and host susceptibility. Rates of residue decomposition, inoculum production and dispersal may be significantly altered by changes in crop rotations, atmospheric carbon dioxide concentration ([CO2]), temperature and precipitation patterns, but the impact may be much greater for regions where inoculum is more limited, such as temperate climates. In regions of non-limiting inoculum, climate change effects will likely be greater on the pathogenic rather than on the saprophytic phase. Although the mechanisms by which abiotic stress influences wheat defences against Fusarium species are unknown, available data would suggest that wheat may be more susceptible to Fusarium infection under future climate conditions. Additional research in this area should be a priority so that breeding efforts and climate resilient management strategies can be developed.

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Analysis of Fusarium graminearum Species Complex from Freshly Harvested Rice in Jiangsu Province (China)

Plant Disease ◽

10.1094/pdis-01-20-0084-re ◽

2020 ◽

Vol 104 (8) ◽

pp. 2138-2143

Author(s):

Fei Dong ◽

Xiao Zhang ◽

Jian Hong Xu ◽

Jian Rong Shi ◽

Yin-Won Lee ◽

...

Keyword(s):

Fusarium Graminearum ◽

Species Complex ◽

Phylogenetic Analyses ◽

Management Strategies ◽

Jiangsu Province ◽

Head Blight ◽

Fusarium Graminearum Species Complex ◽

Rice Samples ◽

Dark Staining ◽

Major Pathogens

Members of Fusarium graminearum species complex (FGSC) are the major pathogens that cause Fusarium head blight (FHB) in cereals worldwide. Symptoms of FHB on rice, including dark staining or browning of rice glumes, were recently observed in Jiangsu Province, China. To improve our understanding of the pathogens involved, 201 FGSC isolates were obtained from freshly harvested rice samples and identified by phylogenetic analyses. Among the 201 FGSC isolates, 196 were F. asiaticum and the remaining 5 were F. graminearum. Trichothecene chemotype and chemical analyses showed that 68.4% of the F. asiaticum isolates were the 3-acetyldeoxynivalenol (3ADON) chemotype and the remainder were the nivalenol (NIV) chemotype. All of the F. graminearum isolates were the 15-acetyldeoxynivalenol chemotype. Pathogenicity assays showed that both the 3ADON and NIV chemotypes of F. asiaticum could infect wheat and rice spikes. FHB severity and trichothecene toxin analysis revealed that F. asiaticum with the NIV chemotype was less aggressive than that with the 3ADON chemotype in wheat, while the NIV-producing strains were more virulent than the 3ADON-producing strains in rice. F. asiaticum isolates with different chemotypes did not show significant differences in mycelial growth, sporulation, conidial dimensions, or perithecial production. These findings would provide useful information for developing management strategies for the control of FHB in China.

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The Spread of a Released Clone of Gibberella zeae from Different Amounts of Infested Corn Residue

Plant Disease ◽

10.1094/pdis-03-11-0218 ◽

2011 ◽

Vol 95 (11) ◽

pp. 1458-1464 ◽

Cited By ~ 9

Author(s):

Melissa D. Keller ◽

Wade E. Thomason ◽

David G. Schmale

Keyword(s):

Fusarium Graminearum ◽

Wheat Cultivar ◽

Gibberella Zeae ◽

Corn Stalk ◽

Head Blight ◽

Inoculum Sources ◽

Length Polymorphisms ◽

Amplified Fragment Length Polymorphisms ◽

Corn Residue ◽

Moderately Resistant

Corn residue is a significant source of inoculum for epidemics of Fusarium head blight (FHB) in wheat and barley, but little is known about the influence of different amounts of corn residue on FHB. We monitored the spread of a released clone of Gibberella zeae (Fusarium graminearum), causal agent of FHB, from small 0.84-m-diameter research plots containing 45, 200, or 410 g of infested corn stalk pieces in winter wheat and barley fields in Virginia over 3 years (2008 to 2010). The fungus was recaptured through the collection of wheat and barley spikes at 0 and 3 m from the source and the released clone was identified in heterogeneous background populations using amplified fragment length polymorphisms. Results showed a slightly greater intensity of recovery of the clone at a greater distance when more infested residue was present. Plots containing larger amounts of inoculum (410 g) generally resulted in a smaller decline of recovery of the clone at 3 m from the source, indicating a greater spread from the larger inoculum source. The clone was also recovered at distances ≥18 m from inoculum sources. Larger amounts of corn residue generally had less influence on clone recovery in plots containing a moderately resistant wheat cultivar than those containing a susceptible wheat cultivar.

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