scholarly journals Molecular Characterization, Fitness, and Mycotoxin Production of Fusarium asiaticum Strains Resistant to Fludioxonil

Plant Disease ◽  
2018 ◽  
Vol 102 (9) ◽  
pp. 1759-1765 ◽  
Author(s):  
J. B. Qiu ◽  
M. Z. Yu ◽  
Q. Yin ◽  
J. H. Xu ◽  
J. R. Shi
Keyword(s):  
Fungal Pathogens ◽  
Toxin Production ◽  
Resistance Mutations ◽  
Head Blight ◽  
Fusarium Asiaticum ◽  
Seedborne Disease ◽  
Induced Mutants ◽  
Fitness Parameters ◽  
Resistant Strains ◽  
Kinase Signaling Pathway

Fludioxonil is used in seedborne disease management of various fungal pathogens, including Fusarium asiaticum, the predominant causal agent of Fusarium head blight in China. In this study, we screened resistant strains from a large number of F. asiaticum strains collected from 2012 to 2016 and found that 4 of 1,000 field strains were highly resistant to fludioxonil. The 50% effective concentration values of the resistant strains and induced mutants ranged from 80 to >400 μg/ml. Compared with field-sensitive strains, all field-collected and laboratory-induced resistant strains exhibited fitness defects in traits including mycelial growth, conidial production, pathogenicity, and sensitivity to osmotic conditions. In the presence of fludioxonil, significantly higher glycerol accumulation was found in sensitive strains but not in resistant individuals. The fludioxonil-resistant strains produced lower amounts of glycerol in liquid culture and lower amounts of trichothecene mycotoxins in rice culture and inoculated wheat spikelets than the fludioxonil-sensitive strains. Sequence analyses of the key genes of the two-component histidine kinase signaling pathway showed various amino acid substitutions in the Os1, Os4, and Os5 genes between field-sensitive and resistant strains or mutants. The results of this study suggest a potential risk of fludioxonil resistance development and a possible influence of resistance mutations on fitness parameters and toxin production in F. asiaticum.

PCR-RFLP for detection of Fusarium graminearum genotypes with resistance to phenamacril

Plant Disease ◽  
2020 ◽  
Author(s):  
Jiao-Sheng Li ◽  
Luo-Yu Wu ◽  
Hui Zhang ◽  
Xiu-Shi Song ◽  
Jian-Xin Wang ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Conventional Method ◽  
Resistance Mutations ◽  
Head Blight ◽  
Fusarium Asiaticum ◽  
Pcr Rflp ◽  
Pcr Products ◽  
Resistant Strains ◽  
Codon Mutation

Phenamacril is a cyanoacrylate fungicide that provides excellent control of Fusarium head blight (FHB) or wheat scab, which is caused predominantly by Fusarium graminearum and Fusarium asiaticum. Previous studies revealed that codon mutations of the myosin-5 gene of Fusarium spp. conferred resistance to phenamacril in vitro lab experiments. In this study, PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) was developed to detect three common mutations (A135T, GCC to ACC at codon 135; S217L, TCA to TTA at codon 217, and E420K, GAA to AAA at codon 420) in F. graminearum induced by fungicide domestication in vitro. PCR products of 841 bp (for mutation of A135T), 802 bp (for mutation of S217L) or 1649 bp (for mutation of E420K) in myosin-5 gene were amplified respectively by appropriate primer pairs. Restriction enzyme KpnⅠ, TasⅠ or DraⅠ was used to distinguish phenamacril-sensitive and -resistant strains with mutation genotypes of A135T, S217L and E420K, respectively. KpnⅠ digested the 841 bp PCR products of phenamacri-resistant strains with codon mutation A135T into two fragments of 256 bp and 585 bp. In contrast, KpnⅠ did not digest the PCR products of sensitive strains. TasⅠ digested the 802 bp PCR products of phenamacril-strains with codon mutation S217L into three fragments of 461 bp, 287bp and 54 bp. In contrast, TasⅠ digestion of the 802 bp PCR products of phenamacril-sensitive strains resulted in only two fragments of 515bp and 287bp. DraⅠ digested the 1649 bp PCR products of phenamacril-resistant strains with codon mutation E420K into two fragments of 932 bp and 717 bp, while the PCR products of phenamacril-sensitive strains was not digested. The three genotypes of resistance mutations were determined by analyzing electrophoresis patterns of the digestion fragments of PCR products. The PCR-RFLP method was evaluated on 48 phenamacril-resistant strains induced by fungicide domestication in vitro and compared with the conventional method (mycelial growth on fungicide-amended agar). The accuracy of the PCR-RFLP method for detecting the three resistant mutation genotypes of F. graminearum to phenamacril was 95.12% compared with conventional method. Bioinformatics analysis revealed that the PCR-RFLP method could also be used to detect the codon mutations of A135T and E420K in F. asiaticum.

scholarly journals Interactions between Head Blight Pathogens: Consequences for Disease Development and Toxin Production in Wheat Spikes

2014 ◽  
Vol 81 (3) ◽  
pp. 957-965 ◽  
Author(s):  
Dorothée Siou ◽  
Sandrine Gélisse ◽  
Valérie Laval ◽  
Sonia Elbelt ◽  
Cédric Repinçay ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Field Experiments ◽  
Field Studies ◽  
Toxin Production ◽  
Head Blight ◽  
Complex Species ◽  
Content Type ◽  
Significant Yield ◽  
Fungal Dna ◽  
Species Specific

ABSTRACTHead blight (HB) is one of the most damaging diseases on wheat, inducing significant yield losses and toxin accumulation in grains. Fungal pathogens responsible for HB include the genusMicrodochium, with two species, and the toxin producer genusFusarium, with several species. Field studies and surveys show that two or more species can coexist within a same field and coinfect the same plant or the same spike. In the current study, we investigated how the concomitant presence ofF. graminearumand another of the HB complex species influences the spike colonization and the toxin production by the fungi. To study these interactions, 17 well-characterized isolates representing five species were inoculated alone or in pairs on wheat spikes in greenhouse and field experiments. The fungal DNA in the grains was estimated by quantitative PCR and toxin contents (deoxynivalenol and nivalenol) by ultraperformance liquid chromatography-UV detection-tandem mass spectrometry. The responses of the different isolates to the presence of a competitor were variable and isolate specific more than species specific. The development of the most aggressive isolates was either unchanged or a slightly increased, while the development of the less aggressive isolates was reduced. The main outcome of the study was that no trend of increased toxin production was observed in coinoculations compared to single inoculations. On the contrary, the amount of toxin produced was often lower than expected in coinoculations. We thus conclude against the hypothesis that the co-occurrence of several HB-causing species in the same field might aggravate the risk linked to fusarium toxins in wheat production.

scholarly journals Emergence of Resistance Mutations in Salmonella enterica Serovar Typhi Against Fluoroquinolones

2017 ◽  
Vol 4 (4) ◽  
Author(s):  
Takashi Matono ◽  
Masatomo Morita ◽  
Koji Yahara ◽  
Ken-ichi Lee ◽  
Hidemasa Izumiya ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Evolutionary Process ◽  
Resistance Mechanisms ◽  
Single Mutation ◽  
Nucleotide Polymorphisms ◽  
Resistance Mutations ◽  
Single Nucleotide ◽  
Salmonella Enterica Serovar Typhi ◽  
Resistant Strains ◽  
Emergence Of Resistance

Abstract Background Little is known about the evolutionary process and emergence time of resistance mutations to fluoroquinolone in Salmonella enterica serovar Typhi. Methods We analyzed S. Typhi isolates collected from returned travelers between 2001 and 2016. Based on ciprofloxacin susceptibility, isolates were categorized as highly resistant (minimum inhibitory concentration [MIC] ≥ 4 μg/mL [CIPHR]), resistant (MIC = 1–2 μg/mL [CIPR]), intermediate susceptible (MIC = 0.12–0.5 μg/mL [CIPI]), and susceptible (MIC ≤ 0.06 μg/mL [CIPS]). Results A total of 107 isolates (33 CIPHR, 14 CIPR, 30 CIPI, and 30 CIPS) were analyzed by whole-genome sequencing; 2461 single nucleotide polymorphisms (SNPs) were identified. CIPS had no mutations in the gyrA or parC genes, while each CIPI had 1 of 3 single mutations in gyrA (encoding Ser83Phe [63.3%], Ser83Tyr [33.3%], or Asp87Asn [3.3%]). CIPHR had the same 3 mutations: 2 SNPs in gyrA (encoding Ser83Phe and Asp87Asn) and a third in parC (encoding Ser80Ile). CIPHR shared a common ancestor with CIPR and CIPI isolates harboring a single mutation in gyrA encoding Ser83Phe, suggesting that CIPHR emerged 16 to 23 years ago. Conclusions Three SNPs—2 in gyrA and 1 in parC—are present in S. Typhi strains highly resistant to fluoroquinolone, which were found to have evolved in 1993–2000, approximately 10 years after the beginning of the ciprofloxacin era. Highly resistant strains with survival advantages arose from strains harboring a single mutation in gyrA encoding Ser83Phe. Judicious use of fluoroquinolones is warranted to prevent acceleration of such resistance mechanisms in the future.

scholarly journals Multiple Influenza A (H3N2) Mutations Conferring Resistance to Neuraminidase Inhibitors in a Bone Marrow Transplant Recipient

2014 ◽  
Vol 58 (12) ◽  
pp. 7188-7197 ◽  
Author(s):  
Alireza Eshaghi ◽  
Sarah Shalhoub ◽  
Paul Rosenfeld ◽  
Aimin Li ◽  
Rachel R. Higgins ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Antiviral Therapy ◽  
Influenza A ◽  
Antiviral Treatment ◽  
Marrow Transplant ◽  
Viral Fitness ◽  
H3n2 Virus ◽  
Resistance Mutations ◽  
Depth Analysis ◽  
Resistant Strains

ABSTRACTImmunocompromised patients are predisposed to infections caused by influenza virus. Influenza virus may produce considerable morbidity, including protracted illness and prolonged viral shedding in these patients, thus prompting higher doses and prolonged courses of antiviral therapy. This approach may promote the emergence of resistant strains. Characterization of neuraminidase (NA) inhibitor (NAI)-resistant strains of influenza A virus is essential for documenting causes of resistance. In this study, using quantitative real-time PCR along with conventional Sanger sequencing, we identified an NAI-resistant strain of influenza A (H3N2) virus in an immunocompromised patient. In-depth analysis by deep gene sequencing revealed that various known markers of antiviral resistance, including transient R292K and Q136K substitutions and a sustained E119K (N2 numbering) substitution in the NA protein emerged during prolonged antiviral therapy. In addition, a combination of a 4-amino-acid deletion at residues 245 to 248 (Δ245-248) accompanied by the E119V substitution occurred, causing resistance to or reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir). Resistant variants within a pool of viral quasispecies arose during combined antiviral treatment. More research is needed to understand the interplay of drug resistance mutations, viral fitness, and transmission.

scholarly journals Constraints of Drug Resistance in Mycobacterium tuberculosis - Prospects for Pharmacological Reversion of Susceptibility to Antibiotics

2017 ◽  
Vol 8 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Aleksandr I. Ilin ◽  
Murat E. Kulmanov ◽  
Ilya S. Korotetskiy ◽  
Marina V. Lankina ◽  
Gulshara K. Akhmetova ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Genetic Heterogeneity ◽  
Multidrug Resistant ◽  
Resistance Mutations ◽  
General Increase ◽  
Drug Induced ◽  
Mdr Tb ◽  
Resistant Strains

Emergence of multidrug resistant strains ofMycobacterium tuberculosis(MDR-TB) threatens humanity. This problem was complicated by the crisis in development of new anti-tuberculosis antibiotics. Induced reversion of drug resistance seems promising to overcome the problem. Successful clinical trial of a new anti-tuberculosis nanomolecular complex FS-1 has demonstrated prospectively of this approach in combating MDR-TB. Several clinical MDR-TB cultures were isolated from sputum samples prior and in the process of the clinical trial. Every isolate was tested for susceptibility to antibiotics and then they were sequenced for comparative genomics. It was found that the treatment with FS-1 caused an increase in the number of antibiotic susceptible strains among Mtb isolates that was associated with a general increase of genetic heterogeneity of the isolates. Observed impairing of phthiocerol dimycocerosate biosynthesis by disruptive mutations inppsACDsubunits indicated a possible virulence remission for the sake of persistence. It was hypothesized that the FS-1 treatment eradicated the most drug resistant Mtb variants from the population by aggravating the fitness cost of drug resistance mutations. Analysis of distribution of these mutations in the global Mtb population revealed that many of them were incompatible with each other and dependent on allelic states of many other polymorphic loci. The latter discovery may explain the negative correlation between the genetic heterogeneity of the population and the level of drug tolerance. To the best of our knowledge, this work was the first experimental confirmation of the drug induced antibiotic resistance reversion by the induced synergy mechanism that previously was predicted theoretically.

scholarly journals A Microbial Fermentation Mixture Reduces Fusarium Head Blight and Promotes Grain Weight but does not impact Septoria tritici blotch

2021 ◽  
Author(s):  
Tony Twamley ◽  
Mark Gaffney ◽  
Angela Feechan
Keyword(s):  
Fusarium Head Blight ◽  
Fungal Pathogens ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Microbial Fermentation ◽  
In Planta ◽  
Head Blight ◽  
Zymoseptoria Tritici ◽  
The Impact

AbstractFusarium graminearum and Zymoseptoria tritici cause economically important diseases of wheat. F. graminearum is one of the primary causal agents of Fusarium head blight (FHB) and Z. tritici is the causal agent of Septoria tritici blotch (STB). Alternative control methods are required in the face of fungicide resistance and EU legislation which seek to cut pesticide use by 2030. Both fungal pathogens have been described as either hemibiotrophs or necrotrophs. A microbial fermentation-based product (MFP) was previously demonstrated to control the biotrophic pathogen powdery mildew, on wheat. Here we investigated if MFP would be effective against the non-biotrophic fungal pathogens of wheat, F. graminearum and Z. tritici. We assessed the impact of MFP on fungal growth, disease control and also evaluated the individual constituent parts of MFP. Antifungal activity towards both pathogens was found in vitro but MFP only significantly decreased disease symptoms of FHB in planta. In addition, MFP was found to improve the grain number and weight, of uninfected and F. graminearum infected wheat heads.

scholarly journals Breeding progress for pathogen resistance is a second major driver for yield increase in German winter wheat at contrasting N levels

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Holger Zetzsche ◽  
Wolfgang Friedt ◽  
Frank Ordon
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Fungal Pathogens ◽  
Large Scale ◽  
Pathogen Resistance ◽  
Wheat Breeding ◽  
Yield Potential ◽  
Head Blight ◽  
Wheat Production ◽  
Over Time

AbstractBreeding has substantially increased the genetic yield potential, but fungal pathogens are still major constraints for wheat production. Therefore, breeding success for resistance and its impact on yield were analyzed on a large panel of winter wheat cultivars, representing breeding progress in Germany during the last decades, in large scale field trials under different fungicide and nitrogen treatments. Results revealed a highly significant effect of genotype (G) and year (Y) on resistances and G × Y interactions were significant for all pathogens tested, i.e. leaf rust, strip rust, powdery mildew and Fusarium head blight. N-fertilization significantly increased the susceptibility to biotrophic and hemibiotrophic pathogens. Resistance was significantly improved over time but at different rates for the pathogens. Although the average progress of resistance against each pathogen was higher at the elevated N level in absolute terms, it was very similar at both N levels on a relative basis. Grain yield was increased significantly over time under all treatments but was considerably higher without fungicides particularly at high N-input. Our results strongly indicate that wheat breeding resulted in a substantial increase of grain yield along with a constant improvement of resistance to fungal pathogens, thereby contributing to an environment-friendly and sustainable wheat production.

A Victorivirus from Fusarium asiaticum, the pathogen of Fusarium head blight in China

2018 ◽  
Vol 164 (1) ◽  
pp. 313-316 ◽  
Author(s):  
Wei Li ◽  
Yunlei Xia ◽  
Haotian Zhang ◽  
Xing Zhang ◽  
Huaigu Chen
Keyword(s):  
Fusarium Head Blight ◽  
Head Blight ◽  
Fusarium Asiaticum

Head blight of durum wheat caused by Fusarium asiaticum

2020 ◽  
Vol 87 (1) ◽  
pp. 39-41
Author(s):  
Keisuke Tomioka ◽  
Akira Kawakami ◽  
Akira Masunaka ◽  
Hiroyuki Sekiguchi ◽  
Keita Kato ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Head Blight ◽  
Fusarium Asiaticum

scholarly journals Investigating Useful Properties of Four Streptomyces Strains Active against Fusarium graminearum Growth and Deoxynivalenol Production on Wheat Grains by qPCR

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 560
Author(s):  
Elena Maria Colombo ◽  
Andrea Kunova ◽  
Claudio Gardana ◽  
Cristina Pizzatti ◽  
Paolo Simonetti ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Plant Pathogens ◽  
Fungal Growth ◽  
Toxin Production ◽  
Fungal Mycelium ◽  
Head Blight ◽  
Wheat Grains ◽  
Streptomyces Spp ◽  
Dual Plate

Streptomyces spp. can be exploited as biocontrol agents (BCAs) against plant pathogens such as Fusarium graminearum, the main causal agent of Fusarium head blight (FHB) and against the contamination of grains with deoxynivalenol (DON). In the present research, four Streptomyces strains active against F. graminearum in dual plate assays were characterized for their ability to colonize detached wheat grains in the presence of F. graminearum and to limit DON production. The pathogen and BCA abundance were assessed by a quantitative real-time PCR, while DON production was assessed by HPLC quantification and compared to ergosterol to correlate the toxin production to the amount of fungal mycelium. Fungal growth and mycotoxin production were assessed with both co-inoculation and late inoculation of the BCAs in vitro (three days post-Fusarium inoculation) to test the interaction between the fungus and the bacteria. The level of inhibition of the pathogen and the toxin production were strain-specific. Overall, a higher level of DON inhibition (up to 99%) and a strong reduction in fungal biomass (up to 71%) were achieved when streptomycetes were co-inoculated with the fungus. This research enabled studying the antifungal efficacy of the four Streptomyces strains and monitoring their development in DON-inducing conditions.

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