Publications by authors named "Sarrah Mbarek"

Article Synopsis
  • * Researchers used single nucleotide polymorphism (SNP) markers to analyze 235 durum wheat accessions, revealing two main genetic groups and significant phenotypic variation related to tan spot resistance over multiple cropping seasons.
  • * The genome-wide association study identified 26 SNPs linked to tan spot resistance, with varying degrees of phenotypic variation explained, and several markers coinciding with previously known SNPs for disease resistance.
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Animals are used for scientific purposes across Africa to benefit humans, animals or the environment. Nonetheless, ethical and regulatory oversight remains limited in many parts of the continent. To strengthen this governance framework, the Pan-African Network for Laboratory Animal Science and Ethics brought together experts from 12 African countries to create an Africa-centric practical guide to facilitate the establishment and appropriate functioning of Institutional Animal Ethics Committees across Africa.

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Climate changes over the past 25 years have led to conducive conditions for invasive and transboundary fungal disease occurrence, including the re-emergence of wheat stem rust disease, caused by f.sp. (Pgt) in East Africa, Europe, and the Mediterranean basin.

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Background: Septoria tritici blotch (STB), caused by Zymoseptoria tritici (Z. tritici), is an important biotic threat to durum wheat in the entire Mediterranean Basin. Although most durum wheat cultivars are susceptible to Z.

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Durum wheat landraces have huge potential for the identification of genetic factors valuable for improving resistance to biotic stresses. Tunisia is known as a hot spot for Septoria tritici blotch disease (STB), caused by the fungus (). In this context, a collection of 3166 Mediterranean durum wheat landraces were evaluated at the seedling and adult stages for STB resistance in the 2016-2017 cropping season under field conditions in Kodia (Tunisia).

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Tan spot (TS), caused by the fugus (), has gained significant importance in the last few years, thereby representing a threat to wheat production in all major wheat-growing regions, including Tunisia. In this context, we evaluated a Mediterranean collection of 549 durum wheat accessions under field conditions for resistance to over two cropping seasons in Jendouba (Tunisia), a hot spot for . The relative disease severities showed significant phenotypic variation from resistance to susceptibility.

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causes tan spot, an important foliar disease of wheat. A collection of . isolates from Tunisia, located in one of the main secondary centers of diversification of durum wheat, was tested for phenotypic race classification based on virulence on a host differential set and for the presence of the necrotrophic effector (NE) genes , , and by PCR analysis.

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Host resistance and fungicide treatments are cornerstones of plant-disease control. Here, we show that these treatments allow sex and modulate parenthood in the fungal wheat pathogen Zymoseptoria tritici. We demonstrate that the Z.

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Culture filtrates (CFs) of the fungal wheat pathogen Zymoseptoria tritici were assayed for necrosis-inducing activity after infiltration in leaves of various wheat cultivars. Active fractions were partially purified and characterized. The necrosis-inducing factors in CFs are proteinaceous, heat stable and their necrosis-inducing activity is temperature and light dependent.

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Zymoseptoria tritici is an economically important pathogen of wheat. However, the molecular basis of pathogenicity on wheat is still poorly understood. Here, we present a global survey of the proteins secreted by this fungus in the apoplast of resistant (cv.

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Fungal plant pathogens, such as Zymoseptoria tritici (formerly known as Mycosphaerella graminicola), secrete repertoires of effectors to facilitate infection or trigger host defence mechanisms. The discovery and functional characterization of effectors provides valuable knowledge that can contribute to the design of new and effective disease management strategies. Here, we combined bioinformatics approaches with expression profiling during pathogenesis to identify candidate effectors of Z.

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The cyclic AMP (cAMP) signaling and mitogen-activated protein (MAP) kinase pathways are the most important signal transduction pathways in eukaryotes. In many plant pathogenic fungi they play pivotal roles in virulence and development. Identification and understanding the role of signal transduction pathways in regulation of cellular responses require robust biochemical techniques.

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Article Synopsis
  • Mycosphaerella graminicola is a significant plant-pathogenic fungus that causes septoria tritici blotch, a disease that negatively impacts wheat yield and quality, posing threats to global food production.
  • The complete sequencing of its genome revealed 21 chromosomes, including eight dispensable ones that can be lost without affecting the fungus, indicating a complex genetic structure influenced by horizontal gene transfer.
  • Comparative analysis showed unusual "mesosynteny" with another Dothideomycete, suggesting rapid chromosomal rearrangements, and highlighted that M. graminicola has fewer genes for breaking down plant cell walls, hinting at a stealthy pathogenic strategy involving protein degradation during infection.
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Plant pathogenic fungi adapt quickly to changing environments including overcoming plant disease resistance genes. This is usually achieved by mutations in single effector genes of the pathogens, enabling them to avoid recognition by the host plant. In addition, horizontal gene transfer (HGT) and horizontal chromosome transfer (HCT) provide a means for pathogens to broaden their host range.

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Meiosis in the haploid plant-pathogenic fungus Mycosphaerella graminicola results in eight ascospores due to a mitotic division following the two meiotic divisions. The transient diploid phase allows for recombination among homologous chromosomes. However, some chromosomes of M.

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We identified and functionally characterized genes encoding three Galpha proteins and one Gbeta protein in the dimorphic fungal wheat pathogen Mycosphaerella graminicola, which we designated MgGpa1, MgGpa2, MgGpa3, and MgGpb1, respectively. Sequence comparisons and phylogenetic analyses showed that MgGPA1 and MgGPA3 are most related to the mammalian Galpha(i) and Galpha(s) families, respectively, whereas MgGPA2 is not related to either of these families. On potato dextrose agar (PDA) and in yeast glucose broth (YGB), MgGpa1 mutants produced significantly longer spores than those of the wild type (WT), and these developed into unique fluffy mycelia in the latter medium, indicating that this gene negatively controls filamentation.

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We have performed a genome-wide analysis of the mimp family of miniature inverted-repeat transposable elements, taking advantage of the recent release of the F. oxysporum genome sequence. Using different approaches, we detected 103 mimp elements, corresponding to 75 nonredundant copies, half of which are located on a single small chromosome.

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With the increase of sequenced fungal genomes, high-throughput methods for functional analyses of genes are needed. We assessed the potential of a new transposon mutagenesis tool deploying a Fusarium oxysporum miniature inverted-repeat transposable element mimp1, mobilized by the transposase of impala, a Tc1-like transposon, to obtain knock-out mutants in Fusarium graminearum. We localized 91 mimp1 insertions which showed good distribution over the entire genome.

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Agitoxin 2 (AgTx2) is a 38-residue scorpion toxin, cross-linked by three disulfide bridges, which acts on voltage-gated K(+) (Kv) channels. Maurotoxin (MTX) is a 34-residue scorpion toxin with an uncommon four-disulfide bridge reticulation, acting on both Ca(2+)-activated and Kv channels. A 39-mer chimeric peptide, named AgTx2-MTX, was designed from the sequence of the two toxins and chemically synthesized.

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The mimp1 element previously identified in the ascomycete fungus Fusarium oxysporum has hallmarks of miniature inverted-repeat transposable elements (MITEs): short size, terminal inverted repeats (TIRs), structural homogeneity, and a stable secondary structure. Since mimp1 has no coding capacity, its mobilization requires a transposase-encoding element. On the basis of the similarity of TIRs and target-site preference with the autonomous Tc1-like element impala, together with a correlated distribution of both elements among the Fusarium genus, we investigated the ability of mimp1 to jump upon expression of the impala transposase provided in trans.

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Scorpion toxins interact with their target ion channels through multiple molecular contacts. Because a "gain of function" approach has never been described to evaluate the importance of the molecular contacts in defining toxin affinity, we experimentally examined whether increasing the molecular contacts between a toxin and an ion channel directly impacts toxin affinity. For this purpose, we focused on two scorpion peptides, the well-characterized maurotoxin with its variant Pi1-like disulfide bridging (MTX(Pi1)), used as a molecular template, and butantoxin (BuTX), used as an N-terminal domain provider.

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Aah I is a 63-residue alpha-toxin isolated from the venom of the Buthidae scorpion Androctonus australis hector, which is considered to be the most dangerous species. We report here the first chemical synthesis of Aah I by the solid-phase method, using a Fmoc strategy. The synthetic toxin I (sAah I) was renatured in DMSO-Tris buffer, purified and subjected to thorough analysis and comparison with the natural toxin.

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CoTX1 (cobatoxin 1) is a 32-residue toxin with three disulphide bridges that has been isolated from the venom of the Mexican scorpion Centruroides noxius Hoffmann. Here we report the chemical synthesis, disulphide bridge organization, 3-D (three-dimensional) solution structure determination, pharmacology on K+ channel subtypes (voltage-gated and Ca2+-activated) and docking-simulation experiments. An enzyme-based cleavage of the synthetic folded/oxidized CoTX1 indicated half-cystine pairs between Cys3-Cys22, Cys8-Cys27 and Cys12-Cys29.

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Pi4 is a short toxin found at very low abundance in the venom of Pandinus imperator scorpions. It is a potent blocker of K(+) channels. Like the other members of the alpha-KTX6 subfamily to which it belongs, it is cross-linked by four disulfide bonds.

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