Project description:Septoria leaf blotch is a worldwide threat for wheat and mainly controlled by the application of synthetic fungicides. The fungal pathogen responsible for this disease, Zymoseptoria tritici, was shown as highly adaptable to its host plant, but also to fungicide challenge. Over the past decades it developed resistance to most fungicides due to target site modifications. Recently isolated strains showed cross-resistance to diverse fungicides and to unrelated drugs, suggesting a resistance mechanism that seems rarer in phytopathogenic fungi, known as multidrug resistance (MDR) in other organisms. In this study we show for two Z. tritici MDR strains, MDR6 and MDR7, enhanced prochloraz efflux sensitive to the modulators amitryptiline and chlorpromazine. Efflux was also inhibited by verapamil in the MDR7strain. Transcriptomics revealed several overexpressed transporter genes in both MDR strains, out of which the expression of the MgMFS1 transporter gene was the strongest and constitutively high in tested MDR field strains. Its inactivation in the MDR6 strain abolished resistance to fungicides with different modes of action revealing its involvement in the MDR phenomenon in Z. tritici.
Project description:Z. tritici is a fungal pathogen causing the disease septoria tritici blotch, one of the most economically devastating foliar diseases in wheat. The molecular basis underlying Z. tritici growth, development and pathogenicity is not fully understood yet. Compared to the genomic investigations in this fungus, little is known about the protein expression at a systematic level. The aim of the project is to construct a comprehensive protein database of Z. tritici growing in nutrient-limiting and rich media and in vivo at a late stage of wheat infection by using 1D gel-based and SCX-based proteomics and subproteomics (intracellular and extracellular) approaches.
Project description:Septoria leaf blotch is a worldwide threat for wheat and mainly controlled by the application of synthetic fungicides. The fungal pathogen responsible for this disease, Zymoseptoria tritici, was shown as highly adaptable to its host plant, but also to fungicide challenge. Over the past decades it developed resistance to most fungicides due to target site modifications. Recently isolated strains showed cross-resistance to diverse fungicides and to unrelated drugs, suggesting a resistance mechanism that seems rarer in phytopathogenic fungi, known as multidrug resistance (MDR) in other organisms. In this study we show for two Z. tritici MDR strains, MDR6 and MDR7, enhanced prochloraz efflux sensitive to the modulators amitryptiline and chlorpromazine. Efflux was also inhibited by verapamil in the MDR7strain. Transcriptomics revealed several overexpressed transporter genes in both MDR strains, out of which the expression of the MgMFS1 transporter gene was the strongest and constitutively high in tested MDR field strains. Its inactivation in the MDR6 strain abolished resistance to fungicides with different modes of action revealing its involvement in the MDR phenomenon in Z. tritici. A total of four strains were compared, two sensitive (IPO323, S6) and two MDR strains (09-ASA-3apz; 09-CB01) with three replicates each. All strains were grown in liquid YPD medium to exponential growth.
Project description:Grapevine red blotch is a recently identified viral disease that was first recognized in the Napa Valley of California. Infected plants showed foliar symptoms similar to leafroll, another grapevine viral disease, on vines testing negative for known grapevine leafroll-associated virus. Later, the Grapevine red blotch virus (GRBV) was independently discovered in the US states of California and New York and was demonstrated to be the causal agent of red blotch disease. Due to its wide occurrence in the US, vector transmission and impacts on grape industry, this virus has the potential to cause serious economic losses. Despite numerous attempts, it was not possible to isolate or visualize viral particles from GRBV infected plants. Consequently, this has hampered the development of a serological assay that would facilitate GRBV detection in grapevine. We therefore decided to explore mass spectrometry approaches in order to quantify GRBV in infected plants and to identify potential biomarkers for viral infection. We present for the first time the physical detection on the protein level of the two GRBV genes V1 (coat protein) and V2 in grapevine tissue lysates. The GRBV coat protein load in leaf petioles was determined to be in the range of 100 to 900 million copies per milligram wet weight by using three heavy isotope labeled reference peptides as internal standards. The V1 copy number per unit wet tissue weight in leaves appeared to be about six times lower, and about 200-times lower in terms of protein concentration in the extractable protein mass than in petioles. We found a consistent upregulation of several enzymes involved in flavonoid biosynthesis in leaf and petiole extracts of GRBV-infected plants by label-free shotgun proteomics, indicating the activation of a defense mechanism against GRBV, a plant response already described for grapevine leafroll associated virus infection on the transcriptome level. Last but not least, we identified some other microorganisms belonging to the grapevine leaf microbiota, two bacterial species (Novosphingobium sp. Rr 2-17 and Methylobacterium) and one virus, Grapevine rupestris stem pitting associated virus.
Project description:Purpose: The powdery mildew fungus, Blumeria graminis, is an obligate biotrophic pathogen of cereals and has significant impact on food security (Dean et al., 2012. Molecular Plant Pathology 13 (4): 414-430. DOI: 10.1111/j.1364-3703.2011.00783.x). Blumeria graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley (Hordeum vulgare L.). We sought to identify small RNAs (sRNAs) from both barley and Bgh that regulate gene expression both within species and cross-kingdom.