Oral Presentations
Total Page：16
File Type：pdf, Size：1020Kb
ORAL PRESENTATIONS KEYNOTE LECTURE KEYNOTE LECTURE Feedback with soil microbes drives plant community composition in temperate ecosystems John Klironomos University of British Columbia, Canada SHORT BIO John Klironomos, Professor, Biology /BRAES Institute, Associate Dean of Research, Irving K. Barber School of Arts and Sciences, The University of British Columbia, Okanagan Campus, Canada. Prof. Klironomos is a fellow of the Royal Society of Canada. His research group “focuses on one group of mycorrhizal fungi (arbuscular mycorrhizal fungi – Phylum Glomeromycota), although they often include other fungi (mycorrhizal, saprobic, pathogenic), and other soil biota as well (e.g., bacteria, protists, fungi, invertebrates), using two approaches in studying mycorrhizal ecology: (a) comparative and manipulative field studies, and (b) controlled experiments under laboratory and greenhouse conditions”. More information may be found at https://biodiversity.ubc.ca/people/faculty/john- klironomos. 1 KEYNOTE LECTURE O1. PLENARY LECTURE I Plant disease susceptibility; on host genes and pathogen effectors controlling infection Guido Van den Ackerveken Plant-Microbe Interactions, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands. [email protected] Susceptibility to infectious diseases caused by pathogens affects most plants in their natural habitat and leads to yield losses in agriculture. But plants are not helpless because their immune system can deal with the vast majority of attackers that our recognized through molecular patterns by specialized receptors. Nevertheless, adapted pathogens have evolved effectors to circumvent or avert host immunity making plants susceptible to these uninvited guests. In addition to the failure of the plant immune system, there are other host processes that contribute to plant disease susceptibility. In my presentation I will discuss the active role that the host plays in supporting disease. Mutation of susceptibility genes can render plants resistant to pathogen attack thereby providing a method for obtaining disease resistant crops. In my presentation I will provide some insight into the translation of our fundamental science from the Arabidopsis-downy mildew system to its use in breeding for resistance in vegetable crops. 2 ORAL PRESENTATIONS O2. Priming of the plant immune responses through epigenetic modifications triggered by a beneficial bacterium Gkizi D.1, Gonzalez Gil A.2, Ntoukakis V.2, Tjamos S.E.1 1 Agricultural University of Athens, School of Crop Science, Laboratory of Plant Pathology 2 School of Life Sciences University of Warwick, UK Numerous epigenetic modifications can be caused by biotic and abiotic factors but only some of them can be inherited to the next generation. The aim of this work was to study the epigenetic background of the inherited resistance of A. thaliana to Verticillium dahliae infection observed in the offspring of plants treated with the biocontrol agent Paenibacillus alvei K165. Transcriptomic analysis in the above ground tissue of K165 treated plants and their offspring revealed significant changes in the expression levels of genes in phenylpronanoid biosynthesis pathway which gives lignin as a final product. This was confirmed by the high lignin levels observed in K165 treated plants and their offspring. The whole genome acetylation levels of resistant plants were found higher than those of control plants using western blot analysis. Moreover, Chromatin Immunoprecipitation experiments have shown a correlation between the expression levels of PDF1.2 and CAD8 genes and the acetylation levels in their promoters. Finally Arabidopsis mutants in CAD genes lost the resistance caused by K165 as well as the inherited resistance. The results of this study demonstrate the importance of epigenetic modifications for the activation of plant immune responses by biocontrol agents. Priming the plants’ immune system using a biocontrol agent can result in offspring with an innate epigenetically inherited resistance to a pathogen. The research work was supported by the Hellenic Foundation for Research and Innovation (HFRI) and the General secretariat for Research and Technology (GSRT). 3 ORAL PRESENTATIONS O3. Roles and interactions of the members of a bacterial consortium along the degradation of the recalcitrant fungicide thiabendazole revealed via multi-omic approach Vasileiadis S.1, Perruchon C.1, Omirou M.2, Scheer B.3, Adrian L.3, Steinbach N.4, Agüera A.5, Chatzinotas A.4, Karpouzas D.G.1 1Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece 2Agricultural Research Institute of Cyprus, Nicosia, Cyprus 3Department Isotope Biogeochemistry and 4Department of Environmental Microbiology, Helmholtz Centre for Environmental Research GmbH – UFZ, Leipzig, Germany 5Department of Chemistry and Physics, University of Almeria, Almeria, Spain Recalcitrant to degradation compounds used in agriculture pose a challenge for environmental management. Thiabendazole (TBZ), a benzimidazole commonly used against postharvest fungal diseases and as anthelminthic in livestock farming, is highly persistent in soil (DT50> 1-2 years) without known microorganisms with potency to degrade it. Our group has recently enriched from soil a bacterial consortium able to rapidly degrade TBZ through cleavage of the benzimidazole ring. However, no pure TBZ-degrading isolate was obtained, despite numerous attempts, suggesting complex interactions between consortium members. We employed a multi-omic approach to elucidate the microbial interactions that maintain the consortium TBZ-degrading capacity complemented by stable isotope probing (SIP). Metagenomics resulted in 19 high quality metagenome assembled genomes (MAGs) with six being dominant. Alongside, SIP 16S-rRNA-gene-amplicon sequencing verified previous group findings of the key degrading role of a Sphingomonas strain comprising the most dominant metagenome bin. RNA sequencing of the consortium supplied with TBZ or succinate, as sole carbon sources, showed the enhanced expression in Sphignomonas of (i) a a carbazole dioxygenase locus having a probable role in the initial transformation step of TBZ (ii) interesting signaling, transport, secretion and conjugation associated genes. RNA data networking analysis suggested the interaction of Sphingomonas with a Hydrogenophaga strain and possible contribution of the latter to the overall cobalamin balance via upregulation of the complete cob locus during TBZ degradation. Proteomics supported the mRNA differential expression patterns with a more stable expression profile over time. On-going metabolomics and associated modeling are expected to elucidate the full metabolic pathway of TBZ. Acknowledgements Dr Vasileiadis is funded by the MSCA-IF-H2020 project EMIGRATE (grant # 749463), Dr Perruchon and Prof. Karpouzas are supported by OMIC-ENGINE (MIS 5002636) funded by the Operational Programme "Competitiveness, Entrepreneurship and Innovation" (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund). http://emigrate.bio.uth.gr / https://www.omic-engine.com 4 ORAL PRESENTATIONS O4. Characterization, Identification and Physiological Studies of a Pigment- producing Tentative Pseudomonas spp. with Antifungal Properties Mitsagga C.1, Giavasis I.1*, Katsoula A.2, Vasileiadis S.2, Karpouzas D.2 and Papadopoulou K.2 1University of Thessaly, Department of Food Technology 2University of Thessaly, Department of Biochemistry and Biotechnology *Corresponding author. Assistant Professor, Lab of Food Microbiology and Biotechnology, End of N. Temponera Street, Karditsa, 43100, Greece. Email: [email protected] A Gram negative, psychrotrophic, alcalophilic bacterium of very small size (<0,45μm) with antifungal properties was isolated randomly in a lab refrigerator and identified by phylogenetic analysis using the 16sRNA, gyrB and rPOD nucleotide sequences. Its physiology, morphology, basic biochemical properties and growth conditions were studied, in addition to its antifungal activity. This rod-shaped bacterium, which produces a melanin-type pigment, was found to be a Pseudomonas species, which so far cannot be fully identified with any of the known species of the genus. It is catalase and oxidase positive, urease negative, exhibits motility, lipase activity and can utilize citric acid. The production of the pigment is dependent on environmental conditions and medium composition and appears as a reversible feature of the bacterium (thus probably controlled by plasmids), which is also fading gradually, along with the antifungal activity, after long preservation of the culture under refrigeration. Fresh cultures, especially under co-cultivation with fungi, can resume and exhibit high antifungal properties. The bacterium has a wide pH range for growth, exhibiting optimal growth at pH 9, is relatively heat resistant up to at least 60°C, and can rapidly outgrow many different fungi (by slowing down, or completely pausing fungal growth), even in fungal selective media, at a pH of ≥4. Its antifungal properties are dependent on the presence of viable cells, and are not due to any extracellular metabolite (no antimicrobial activity was found in cell culture filtrates). The bacterium showed significant inhibition of growth of Penicillium expansum, Aspergillus flavus, Rhizoctonia solani and Rhodotorula mucilaginosa in synthetic media, based on well diffusion assay on agar media, and on the measurement of target cell population in liquid cultures