TaWRKY10 transcription factor is a novel Jasmonic Acid signalling regulator involved in immunity against Septoria tritici blotch disease in wheat

SummaryZymoseptoria triticiis a filamentous fungus causing Septoria tritici blotch in wheat. The pathogen has a narrow host range and infections of grasses other than susceptible wheat are blocked early after stomatal penetration. During these abortive infections the fungus shows a markedly different expression pattern. However, the underlying mechanisms causing differential gene expression during host and non-host interaction are largely unknown, but likely include transcriptional regulators responsible for the onset of an infection program in compatible hosts. In the rice blast pathogenMagnaporthe oryzae, MoCOD1, a member of the fungal Zn(II)2Cys6transcription factor family, has been shown to directly affect pathogenicity. Here, we analyse the role of the putative transcription factor Zt107320, a homolog of MoCOD1, during infection of compatible and incompatible hosts byZ. tritici. We show for the first time thatZt107320is differentially expressed in host versus non-host infections and that lower expression corresponds to an incompatible infection of non-hosts. Applying reverse genetics approaches we further show that Zt107320 regulates the dimorphic switch as well as the growth rate ofZ. triticiand affects fungal cell wall compositionin vitro. Moreover, ΔZt107320mutants showed reduced virulence during compatible infections of wheat. We conclude that Zt107320 directly influences pathogen fitness and propose that Zt107320 regulates growth processes and pathogenicity during infection. Our results suggest that this putative transcription factor is involved in discriminating compatible and non-compatible infections.

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QTL Mapping of Seedling and Adult Plant Resistance to Septoria Tritici Blotch in Winter Wheat cv. Mandub (Triticum aestivum L.)

Agronomy ◽

10.3390/agronomy11061108 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1108

Author(s):

Dominika Piaskowska ◽

Urszula Piechota ◽

Magdalena Radecka-Janusik ◽

Paweł Czembor

Keyword(s):

Mapping Population ◽

Triticum Aestivum L ◽

Seedling Stage ◽

Septoria Tritici Blotch ◽

Septoria Tritici ◽

Adult Plant ◽

Resistance Locus ◽

Phenotypic Variance ◽

Breeding Programs ◽

Plant Stage

Septoria tritici blotch (STB) is one of the most devastating foliar diseases of wheat worldwide. Host resistance is the most economical and safest method of controlling the disease, and information on resistance loci is crucial for effective breeding for resistance programs. In this study we used a mapping population consisting of 126 doubled-haploid lines developed from a cross between the resistant cultivar Mandub and the susceptible cultivar Begra. Three monopycnidiospore isolates of Z. tritici with diverse pathogenicity were used to test the mapping population and parents’ STB resistance at the seedling stage (under a controlled environment) and adult plant stage (polytunnel). For both types of environments, the percentage leaf area covered by necrosis (NEC) and pycnidia (PYC) was determined. A linkage map comprising 5899 DArTSNP and silicoDArT markers was used for the quantitative trait loci (QTL) analysis. The analysis showed five resistance loci on chromosomes 1B, 2B and 5B, four of which were derived from cv. Mandub. The location of QTL detected in our study on chromosomes 1B and 5B may suggest a possible identity or close linkage with Stb2/Stb11/StbWW and Stb1 loci, respectively. QStb.ihar-2B.4 and QStb.ihar-2B.5 detected on chromosome 2B do not co-localize with any known Stb genes. QStb.ihar-2B.4 seems to be a new resistance locus with a moderate effect (explaining 29.3% of NEC and 31.4% of PYC), conferring resistance at the seedling stage. The phenotypic variance explained by QTL detected in cv. Mandub ranged from 11.9% to 70.0%, thus proving that it is a good STB resistance source and can potentially be utilized in breeding programs.

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Have we finally opened the door to understanding Septoria tritici blotch disease in wheat?

New Phytologist ◽

10.1111/nph.14502 ◽

2017 ◽

Vol 214 (2) ◽

pp. 493-495 ◽

Cited By ~ 5

Author(s):

Peter S. Solomon

Keyword(s):

Septoria Tritici Blotch ◽

Septoria Tritici

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The impact of Septoria tritici Blotch disease on wheat: An EU perspective

Fungal Genetics and Biology ◽

10.1016/j.fgb.2015.04.004 ◽

2015 ◽

Vol 79 ◽

pp. 3-7 ◽

Cited By ~ 185

Author(s):

Helen Fones ◽

Sarah Gurr

Keyword(s):

Septoria Tritici Blotch ◽

Septoria Tritici ◽

The Impact

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Microsatellite markers provide evidence for sexual reproduction of Mycosphaerella graminicola in Saskatchewan

Genome ◽

10.1139/g04-036 ◽

2004 ◽

Vol 47 (5) ◽

pp. 789-794 ◽

Cited By ~ 20

Author(s):

M Razavi ◽

G R Hughes

Keyword(s):

Genetic Diversity ◽

Genetic Variability ◽

Sexual Reproduction ◽

Primary Source ◽

Mycosphaerella Graminicola ◽

Septoria Tritici Blotch ◽

Septoria Tritici ◽

Allelic Series ◽

Evolutionary Potential ◽

Wheat Field

This study examined the genetic structure of a Saskatchewan population of Mycosphaerella graminicola, cause of the foliar disease Septoria tritici blotch of wheat. Such knowledge is valuable for understanding the evolutionary potential of this pathogen and for developing control strategies based on host resistance. Nine pairs of single-locus microsatellite primers were used to analyze the genomic DNA of 90 isolates of M. graminicola that were collected using a hierarchical sampling procedure from different locations, leaves, and lesions within a wheat field near Saskatoon. Allelic series at eight different loci were detected. The number of alleles per locus ranged from one to five with an average of three alleles per locus. Genetic diversity values ranged from 0.04 to 0.67. Partitioning the total genetic variability into within- and among-location components revealed that 88% of the genetic variability occurred within locations, i.e., within areas of 1 m2, but relatively little variability occurred among locations. Low variability among locations and a high degree of variability within locations would result if the primary source of inoculum was airborne ascospores, which would be dispersed uniformly within the field. This finding was confirmed by gametic disequilibrium analysis and suggests that the sexual reproduction of M. graminicola occurs in Saskatchewan.Key words: Mycosphaerella graminicola, SSR markers, sexual reproduction, genetic diversity.

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Accuracy of within- and among-family genomic prediction for Fusarium head blight and Septoria tritici blotch in winter wheat

Theoretical and Applied Genetics ◽

10.1007/s00122-018-3264-6 ◽

2018 ◽

Vol 132 (4) ◽

pp. 1121-1135 ◽

Cited By ~ 14

Author(s):

Cathérine Pauline Herter ◽

Erhard Ebmeyer ◽

Sonja Kollers ◽

Viktor Korzun ◽

Tobias Würschum ◽

...

Keyword(s):

Winter Wheat ◽

Fusarium Head Blight ◽

Genomic Prediction ◽

Septoria Tritici Blotch ◽

Septoria Tritici ◽

Head Blight

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Characterisation of an antimicrobial and phytotoxic ribonuclease secreted by the fungal wheat pathogen Zymoseptoria tritici

10.1101/130393 ◽

2017 ◽

Cited By ~ 1

Author(s):

Graeme J. Kettles ◽

Carlos Bayon ◽

Caroline A. Sparks ◽

Gail Canning ◽

Kostya Kanyuka ◽

...

Keyword(s):

Expression Pattern ◽

Effector Proteins ◽

Yeast Cells ◽

Septoria Tritici Blotch ◽

Septoria Tritici ◽

List Type ◽

Expression Systems ◽

Zymoseptoria Tritici ◽

Loop Region

Abstract-The fungus Zymoseptoria tritici is the causal agent of Septoria Tritici Blotch (STB) disease of wheat leaves. Z. tritici secretes many functionally uncharacterised effector proteins during infection. Here we characterised a secreted ribonuclease (Zt6) with an unusual biphasic expression pattern.-Transient expression systems were used to characterise Zt6, and mutants thereof, in both host and non-host plants. Cell-free protein expression systems monitored impact of Zt6 protein on functional ribosomes, and in vitro assays of cells treated with recombinant Zt6 determined toxicity against bacteria, yeasts and filamentous fungi.-We demonstrated that Zt6 is a functional ribonuclease and that phytotoxicity is dependent on both the presence of a 22-amino acid N-terminal “loop” region and its catalytic activity. Zt6 selectively cleaves both plant and animal rRNA species, and is toxic to wheat, tobacco, bacterial and yeast cells but not to Z. tritici itself.-Zt6 is the first Z. tritici effector demonstrated to have a likely dual functionality. The expression pattern of Zt6 and potent toxicity towards microorganisms suggests that whilst it may contribute to the execution of wheat cell death, it is also likely to have an important secondary function in antimicrobial competition and niche protection.

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Prevalence of QoI resistance and mtDNA diversity in the Irish Zymoseptoria tritici population

Irish Journal of Agricultural and Food Research ◽

10.2478/ijafr-2019-0004 ◽

2019 ◽

Vol 58 (1) ◽

pp. 27-33

Author(s):

S. Kildea ◽

D.E. Bucar ◽

F. Hutton ◽

S. de la Rosa ◽

T.E. Welch ◽

...

Keyword(s):

Septoria Tritici Blotch ◽

Septoria Tritici ◽

Entire Group ◽

Zymoseptoria Tritici ◽

Qoi Fungicides ◽

Quinone Outside Inhibitor ◽

Strain Collection ◽

Increased Sensitivity ◽

Mtdna Diversity

Abstract The emergence and spread of Quinone outside Inhibitor (QoI) fungicide resistance in the Irish Zymoseptoria tritici population in the early 2000s had immediate impacts on the efficacy of the entire group of fungicides for the control of septoria tritici blotch. As a result, a dramatic reduction in the quantities applied to winter wheat occurred in the following seasons. Even in the absence of these fungicides, the frequency of the resistance allele, G143A in the pathogens mtDNA has remained exceptionally high (>97%), and as such, it can be anticipated that continued poor efficacy of current QoI fungicides will be observed. Amongst the isolates with G143A, differences in sensitivity to the QoI pyraclostrobin were observed in vitro. The addition of the alternative oxidase (AOX) inhibitor salicylhydroxamic acid increased sensitivity in these isolates, suggesting some continued impairment of respiration by the QoI fungicides, albeit weak. Interestingly, amongst those tested, the strains from a site with a high frequency of inserts in the MFS1 transporter gene known to enhance QoI efflux did not exhibit this increase in sensitivity. A total of 19 mtDNA haplotypes were detected amongst the 2017 strain collection. Phylogenetic analysis confirmed the suggestion of a common ancestry of all the haplotypes, even though three of the haplotypes contained at least one sensitive strain.

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

European Journal of Plant Pathology ◽

10.1007/s10658-021-02396-4 ◽

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.

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Differential dynamics of microbial community networks help identify microorganisms interacting with residue-borne pathogens: the case of Zymoseptoria tritici in wheat

10.1101/587667 ◽

2019 ◽

Author(s):

Lydie Kerdraon ◽

Matthieu Barret ◽

Valérie Laval ◽

Frédéric Suffert

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Fungal Pathogen ◽

Crop Residues ◽

Septoria Tritici Blotch ◽

Septoria Tritici ◽

Zymoseptoria Tritici ◽

Essential Information ◽

Linear Discriminant ◽

Network Analyses

AbstractBackgroundWheat residues are a crucial determinant of the epidemiology of Septoria tritici blotch, as they support the sexual reproduction of the causal agent Zymoseptoria tritici. We aimed to characterize the effect of infection with this fungal pathogen on the microbial communities present on wheat residues, and to identify microorganisms interacting with it. We used metabarcoding to characterize the microbiome associated with wheat residues placed outdoors, with and without preliminary Z. tritici inoculation, comparing a first set of residues in contact with the soil and a second set without contact with the soil, on four sampling dates in two consecutive years.ResultsThe diversity of the tested conditions, leading to the establishment of different microbial communities according to the origins of the constitutive taxa (plant only, or plant and soil), highlighted the effect of Z. tritici on the wheat residue microbiome. Several microorganisms were affected by Z. tritici infection, even after the disappearance of the pathogen. Linear discriminant analyses and ecological network analyses were combined to describe the communities affected by infection. The number of fungi and bacteria promoted or inhibited by inoculation with Z. tritici decreased over time, and was smaller for residues in contact with the soil. The interactions between the pathogen and other microorganisms appeared to be mostly indirect, despite the strong position of the pathogen as a keystone taxon in networks. Direct interactions with other members of the communities mostly involved fungi, including other wheat pathogens. Our results provide essential information about the alterations to the microbial community in wheat residues induced by the mere presence of a fungal pathogen, and vice versa. Species already described as beneficial or biocontrol agents were found to be affected by pathogen inoculation.ConclusionsThe strategy developed here can be viewed as a proof-of-concept focusing on crop residues as a particularly rich ecological compartment, with a high diversity of fungal and bacterial taxa originating from both the plant and soil compartments, and for Z. tritici-wheat as a model pathosystem. By revealing putative antagonistic interactions, this study paves the way for improving the biological control of residue-borne diseases.

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