Resistance and virulence variability in wheat–Zymoseptoria tritici interactions

2020 ◽  
Vol 71 (7) ◽  
pp. 645
Author(s):  
Mojgan Mahboubi ◽  
Reza Talebi ◽  
Mostafa Aghaee Sarbarzeh ◽  
Amir Mohammad Naji ◽  
Rahim Mehrabi
Keyword(s):  
Resistance Gene ◽  
Effective Resistance ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Resistance Response ◽  
Breeding Programs ◽  
Wheat Genotypes ◽  
Broad Spectrum Resistance ◽  
Important Disease

Septoria tritici blotch (STB), caused by Zymoseptoria tritici, is an important disease of wheat worldwide. This study was performed to investigate the efficacy of Stb genes against 10 isolates of Z. tritici and to elucidate the resistance response pattern of 185 wheat genotypes to STB. The 10 isolates showed different virulence patterns on the Stb differentials. Effectiveness determination showed that most Stb genes (particularly Stb1–Stb9) were ineffective against the 10 isolates, whereas Kavkaz-K4500 (possessing Stb10, Stb12), Arina and Riband (possessing Stb15), and M3 (possessing Stb16 and Stb17) were resistant to all isolates tested. Of the 185 wheat genotypes, 72% were susceptible to all isolates, indicating that these genotypes lacked any effective resistance genes at the seedling stage against the isolates used. The remaining 51 genotypes showed specific resistance to one or more isolates, suggesting that they contain at least one effective resistance gene. Six genotypes were resistant to all isolates, indicating that they may possess broad-spectrum resistance gene(s) or a combination of diverse uncharacterised Stb genes that could be effectively used in breeding programs.

scholarly journals Presence of ice-nucleating Pseudomonas on wheat leaves promotes Septoria tritici blotch disease (Zymoseptoria tritici) via a mutually beneficial interaction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Helen N. Fones
Keyword(s):  
Frost Damage ◽  
Ice Nucleation ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Bacterial Populations ◽  
Wheat Leaf ◽  
Ina Bacteria ◽  
Wheat Leaves ◽  
Important Disease

Abstract Zymoseptoria tritici causes Septoria tritici blotch (STB) of wheat, an economically important disease causing yield losses of up to 10% despite the use of fungicides and resistant cultivars. Z. tritici infection is symptomless for around 10 days, during which time the fungus grows randomly across the leaf surface prior to entry through stomata. Wounded leaves show faster, more extensive STB, suggesting that wounds facilitate fungal entry. Wheat leaves also host epiphytic bacteria; these include ice-nucleating (INA+) bacteria, which induce frost damage at warmer temperatures than it otherwise occurs. Here, STB is shown to be more rapid and severe when wheat is exposed to both INA+ bacteria and sub-zero temperatures. This suggests that ice-nucleation-induced wounding of the wheat leaf provides additional openings for fungal entry. INA+ bacterial populations are shown to benefit from the presence of Z. tritici, indicating that this microbial interaction is mutualistic. Finally, control of INA+ bacteria is shown to reduce STB.

scholarly journals Behavior of Spanish durum wheat genotypes against Zymoseptoria tritici: resistance and susceptibility

2021 ◽  
Vol 19 (3) ◽  
pp. e1002-e1002
Author(s):  
Rafael Porras ◽  
Keyword(s):  
Durum Wheat ◽  
Agronomic Traits ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Sources Of Resistance ◽  
Breeding Lines ◽  
Wheat Genotypes ◽  
Commercial Cultivars ◽  
Growth Chambers

Aim of study: Septoria tritici blotch (STB), caused by the fungus Zymoseptoria tritici, is one of the most important wheat diseases worldwide, affecting both bread and durum wheat. The lack of knowledge about the interaction of durum wheat with Z. tritici, together with limited resources of resistant durum wheat material, have both led to a rising threat for durum wheat cultivation, particularly in the Mediterranean Basin. In Spain, STB has increased its incidence in the last few years, leading to higher costs of fungicide applications to control the disease. Therefore, identification of new sources of resistance through wheat breeding stands out as an efficient method of facing STB. Area of study: The experimental study was conducted in growth chambers at the IFAPA facilities in Córdoba (Spain). Material and methods: The percentage of necrotic leaf area, the disease severity, and the pycnidium development through image analysis were evaluated from 48 durum wheat Spanish accessions (breeding lines and commercial cultivars) in growth chambers against an isolate of Z. tritici from Córdoba. Main results: Two breeding lines and six commercial cultivars showed resistant responses by limiting STB development through the leaf or its reproduction ability, while the other 40 accessions presented a susceptible response. Research highlights: Provided these resources of resistance in Spanish durum wheat genotypes, future breeding programs could be developed, incorporating both agronomic traits and resistance to STB.

scholarly journals Ranking Quantitative Resistance to Septoria tritici Blotch in Elite Wheat Cultivars Using Automated Image Analysis

2018 ◽  
Vol 108 (5) ◽  
pp. 568-581 ◽  
Author(s):  
Petteri Karisto ◽  
Andreas Hund ◽  
Kang Yu ◽  
Jonas Anderegg ◽  
Achim Walter ◽  
...  
Keyword(s):  
Image Analysis ◽  
Quantitative Resistance ◽  
Major Gene ◽  
Growing Season ◽  
Automated Image Analysis ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Wheat Cultivars ◽  
Zymoseptoria Tritici ◽  
Breeding Programs

Quantitative resistance is likely to be more durable than major gene resistance for controlling Septoria tritici blotch (STB) on wheat. Earlier studies hypothesized that resistance affecting the degree of host damage, as measured by the percentage of leaf area covered by STB lesions, is distinct from resistance that affects pathogen reproduction, as measured by the density of pycnidia produced within lesions. We tested this hypothesis using a collection of 335 elite European winter wheat cultivars that was naturally infected by a diverse population of Zymoseptoria tritici in a replicated field experiment. We used automated image analysis of 21,420 scanned wheat leaves to obtain quantitative measures of conditional STB intensity that were precise, objective, and reproducible. These measures allowed us to explicitly separate resistance affecting host damage from resistance affecting pathogen reproduction, enabling us to confirm that these resistance traits are largely independent. The cultivar rankings based on host damage were different from the rankings based on pathogen reproduction, indicating that the two forms of resistance should be considered separately in breeding programs aiming to increase STB resistance. We hypothesize that these different forms of resistance are under separate genetic control, enabling them to be recombined to form new cultivars that are highly resistant to STB. We found a significant correlation between rankings based on automated image analysis and rankings based on traditional visual scoring, suggesting that image analysis can complement conventional measurements of STB resistance, based largely on host damage, while enabling a much more precise measure of pathogen reproduction. We showed that measures of pathogen reproduction early in the growing season were the best predictors of host damage late in the growing season, illustrating the importance of breeding for resistance that reduces pathogen reproduction in order to minimize yield losses caused by STB. These data can already be used by breeding programs to choose wheat cultivars that are broadly resistant to naturally diverse Z. tritici populations according to the different classes of resistance.

scholarly journals A wheat cysteine-rich receptor-like kinase confers broad-spectrum resistance against Septoria tritici blotch

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cyrille Saintenac ◽  
Florence Cambon ◽  
Lamia Aouini ◽  
Els Verstappen ◽  
Seyed Mahmoud Tabib Ghaffary ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Durable Resistance ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Disease Resistance Gene ◽  
Evolutionary Dynamic ◽  
Zymoseptoria Tritici ◽  
Broad Spectrum Resistance ◽  
Receptor Like Kinase ◽  
Synthetic Wheats

AbstractThe poverty of disease resistance gene reservoirs limits the breeding of crops for durable resistance against evolutionary dynamic pathogens. Zymoseptoria tritici which causes Septoria tritici blotch (STB), represents one of the most genetically diverse and devastating wheat pathogens worldwide. No fully virulent Z. tritici isolates against synthetic wheats carrying the major resistant gene Stb16q have been identified. Here, we use comparative genomics, mutagenesis and complementation to identify Stb16q, which confers broad-spectrum resistance against Z. tritici. The Stb16q gene encodes a plasma membrane cysteine-rich receptor-like kinase that was recently introduced into cultivated wheat and which considerably slows penetration and intercellular growth of the pathogen.

scholarly journals Ranking quantitative resistance to Septoria tritici blotch in elite wheat cultivars using automated image analysis

2017 ◽  
Author(s):  
Petteri Karisto ◽  
Andreas Hund ◽  
Kang Yu ◽  
Jonas Anderegg ◽  
Achim Walter ◽  
...  
Keyword(s):  
Image Analysis ◽  
Quantitative Resistance ◽  
Major Gene ◽  
Growing Season ◽  
Automated Image Analysis ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Wheat Cultivars ◽  
Zymoseptoria Tritici ◽  
Breeding Programs

AbstractQuantitative resistance is likely to be more durable than major gene resistance for controlling Septoria tritici blotch (STB) on wheat. Earlier studies hypothesized that resistance affecting the degree of host damage, as measured by the percentage of leaf area covered by STB lesions, is distinct from resistance that affects pathogen reproduction, as measured by the density of pycnidia produced within lesions. We tested this hypothesis using a collection of 335 elite European winter wheat cultivars that was naturally infected by a diverse population of Zymoseptoria tritici in a replicated field experiment. We used automated image analysis (AIA) of 21420 scanned wheat leaves to obtain quantitative measures of conditional STB intensity that were precise, objective, and reproducible. These measures allowed us to explicitly separate resistance affecting host damage from resistance affecting pathogen reproduction, enabling us to confirm that these resistance traits are largely independent. The cultivar rankings based on host damage were different from the rankings based on pathogen reproduction, indicating that the two forms of resistance should be considered separately in breeding programs aiming to increase STB resistance. We hypothesize that these different forms of resistance are under separate genetic control, enabling them to be recombined to form new cultivars that are highly resistant to STB. We found a significant correlation between rankings based on automated image analysis and rankings based on traditional visual scoring, suggesting that image analysis can complement conventional measurements of STB resistance, based largely on host damage, while enabling a much more precise measure of pathogen reproduction. We showed that measures of pathogen reproduction early in the growing season were the best predictors of host damage late in the growing season, illustrating the importance of breeding for resistance that reduces pathogen reproduction in order to minimize yield losses caused by STB. These data can already be used by breeding programs to choose wheat cultivars that are broadly resistant to naturally diverse Z. tritici populations according to the different classes of resistance.

scholarly journals Comparative Transcriptomics Reveals How Wheat Responds to Infection by Zymoseptoria tritici

2018 ◽  
Vol 31 (4) ◽  
pp. 420-431 ◽  
Author(s):  
Xin Ma ◽  
Beat Keller ◽  
Bruce A. McDonald ◽  
Javier Palma-Guerrero ◽  
Thomas Wicker
Keyword(s):  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Pathogenesis Related ◽  
Genes Encoding ◽  
Asymptomatic Phase ◽  
Related Proteins ◽  
Late Stages ◽  
Multiple Pathogen ◽  
Important Disease

The fungus Zymoseptoria tritici causes septoria tritici blotch (STB) on wheat, an important disease globally and the most damaging wheat disease in Europe. Despite the global significance of STB, the molecular basis of wheat defense against Z. tritici is poorly understood. Here, we use a comparative transcriptomic study to investigate how wheat responds to infection by four distinct strains of Z. tritici. We examined the response of wheat across the entire infection cycle, identifying both shared responses to the four strains and strain-specific responses. We found that the early asymptomatic phase is characterized by strong upregulation of genes encoding receptor-like kinases and pathogenesis-related proteins, indicating the onset of a defense response. We also identified genes that were differentially expressed among the four fungal strains, including genes related to defense. Genes involved in senescence were induced during both the asymptomatic phase and at late stages of infection, suggesting manipulation of senescence processes by both the plant and the pathogen. Our findings illustrate the need, when identifying important genes affecting disease resistance in plants, to include multiple pathogen strains.

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

Agronomy ◽  
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.

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

2017 ◽  
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.

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

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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