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The 6th Congress of European Microbiologist (FEMS 2015), Maastricht, The Netherlands 7th – 11th June 2015
International meetings such as the FEMS 2015 are unmissable dates on microbiologists´ agendas. This year, the biannual Conference was celebrated in Maastricht – a lovely, history-rich and multicultural city in the south east of The Netherlands, but also the place where the Treaty, which finally led to the creation of the European Union, was signed in February 1992. This year´s meeting attracted almost 2000 researchers from around the world and it was structured in 32 symposia, 21 workshops, 8 special events and 3 poster networking sessions. In total, there was an impressive collection of talks and posters which included more than 350 lectures and around 1600 posters. Sessions of particular interest for BSPP members were those dedicated to plant -microbe interactions, cell polarity and virulence, horizontal gene transfer and evolution, fungal plant pathogens, cyclic di-nucleotides in bacteria, fungal bacterial interactions, natural productions including secondary metabolites and the Type VI Secretion System.
The conference talks were opened with two plenary talks on Giant viruses and Human microbiome by Jean-Michel Claverie and Janet K. Jansson, respectively. The second day was kicked off by Pierre de Wit who gave an extraordinary plenary talk on the plant immune system and fungal effectors, but mainly focussed on the co-evolution of the interaction between fungal pathogens and their plant host: an extraordinary battle for the survival.
Other remarkable highlights of the meeting are summarized below. Julia Vorholt described her current research on the isolation, characterisation and genome sequencing of phyllospheric bacteria. It was also great to have a general view on how phyllosphere bacteria change their gene expression profiles in this complex niche. Victor Carrion (in representation of Jos Raaijmakers) told us about the detection of metabolite production directly from live microbial colonies, as well as the production of sulphur-derivative volatile compounds by a plant-associated Burkholderia strain. The identified sulphur compounds resulted to show great potential to inhibit the growth of phytopathogenic fungi. Natalia Requena discussed the presence of effector proteins in mycorrhizal fungi, their similarities with those of plant pathogenic fungi and the importance of these effectors for establishing a successful symbiosis. Clay Fuqua gave a great talk on the regulation of the cell polarity in Agrobacterium tumafaciens and its implication in plant colonisation. Christoph Engl delved into the role of c-di-GMP in the virulence of Pseudomonas syringae, mainly through the characterisation of a novel dual function GGDEF/EAL protein. J. Allan Downie shed light to the implication of quorum sensing for nodule infection in Rhizobium leguminosarum. Rob Lavigne told us about how bacteriophage genes are expressed during bacterial infection and how this infection alters the metabolic profile of the host. It was also really exciting to attend Gabriel Waksman, Joseph Mougous, Eric Cascales and Marek Basler talks on structure and mechanisms of bacterial secretion – one of the most covered topics during the FEMS 2015 conference.
In Masstricht, I also had the excellent opportunity of presenting my work on the isolation, characterisation and sequencing of generalised transducing bacter iophages infect ing plantassociated bacteria – including biocontrol agents and pythopathogens belonging to Serratia and Dickeya genera. For this, I would sincerely like to thank BSPP for the very generous support provided to help my attendance at this fantastic conference; but also to allow me to come back to The Netherlands nine years after my stay in the Peter Bakkers’ group in Utrecht (Plantmicrobe Interactions, Faculty of Science).
Miguel A. Matilla Spanish Research Council (EEZCSIC), Granada, Spain
I was offered the opportunity to present my poster entitled ‘Characterising the virome of the entomopathogenic fungus Beauveria bassiana‘ in the ‘Virome’ poster session and to give a short overview of my work during the ‘Virology’ poster discussion session.
As a virologist, for me the highlight of FEMS 2015 was Professor Jean-Michel Claverie’s plenary lecture on giant viruses isolated from marine protozoa. Unlike the tiny and minimalistic entities I am used to working with, these giant viruses consist of near micron-sized particles, contain double-stranded DNA genomes of more than 1 Mbp, comparable to that of a bacterium, and encode hundreds of proteins. However, only a small percentage ca. 10% of these putative open reading frames exhibit a similarity to proteins of known functions. Interestingly, a large number of the viral gene products appear to be implicated in translation, a process necessary for the virus replication cycle but usually carried out using the host cell’s machinery. Professor Claverie focused on the already renowned mimivirus together with two more recently discovered giant viruses designated as pandoravirus and pithovirus, the latter isolated from a layer of Siberian permafrost approximately 30,000 years old.
Additionally, I found particularly interesting Dr Philippe Marliere’s presentation ‘Accept no limit: why and how to restart chemical evolution in microorganisms’ in the context of the ‘High throughput screening technologies’ symposium. Dr Marliere described how a genetically engineered Escherichia coli strain unable to synthesise thymine was gradually adjusted to using 5- chlorouracil, a toxic chemical substance. Briefly, exposure of E. coli to sub-lethal concentrations of 5-chlorouracil under strictly controlled conditions provided an environment that favoured adaptive mutations which allowed the bacteria to tolerate and use 5-chlorouracil instead of thymine. After 1000 E. coli generations and an ever-increasing ratio of 5- chlorouracil:thymine in the culture medium, bacteria capable to survive and proliferate solely using 5-chlorouracil were identified.
Since I have a partially medical background, Professor Janet Jansson’s plenary lecture on the (human) microbiome also appealed to me. A number of high-throughput technologies are currently used in order to elucidate the composition and the function or the microbial communities in the gut and it was found that specific bacterial species, proteins and metabolites are associated with different types of inflammatory bowel disease (IBD). I was especially fascinated by a case study, a female patient suffering from severe IBD who did not respond to any of the conventional treatments. The patient exhibited an unusual profile of gut microbiome and was eventually cured when her husband’s ‘normal’ gut microbiome was transferred to her by fecal transplantation. In summary, attending FEMS 2015 gave me the opportunity to present my recent research findings to a wide audience, helped me expand my scientific horizons by exposing me to high-quality science quite different from my own and was a good opportunity for networking.
I would like to express my gratitude to the BSPP for the financial support.
Ioly Kotta-Loizou Imperial College London
My research focuses on identifying Fg effectors that are able to suppress wheat defence responses in fully susceptible cultivars infected by Fg. To test putative Fg effectors in planta, I use a Barley Stripe mosaic virus-mediated overexpression system. For this reason, the two sessions at FEMS entitled ‘Fungal plant pathogens’ and ‘Fungal cell biology’ were of great interest for me, covering recent topics on new effector discoveries, fungal sequencing, transport of peroxisomes and endosomes.
A workshop lecture given by Prof. Bart Thomma from Wageningen University entitled ‘Pathogenomics of Verticillium wilt diseases’ was very useful for my PhD. The main research subject of Prof. Thomma’s lab is to understand fundamental processes in plant pathogenic fungi and oomycetes that occur in the rhizosphere, and the interactions with bacteria and their host plants. He showed that the avirulence gene Ave1 in V. dahliae interacts with plant chitinases. This interaction was demonstrated in vitro and the mutant Äave1 strain was unable to infect tomato. However, when a gene encoding chitinase in tomato plants was silenced, the mutant strain ∆ave1 was able to infect the plant. In addition, he compared two V. dahliae strains that were assembled (telomere-to-telomere) using long-read sequencing technology. Genomic rearrangements and structural variations were observed between these two strains. These variations could contribute to the evolution of virulence as these regions are enriched for in plantaexpressed effector genes encoding secreted proteins. Based on his finding, it was hypothesised that evolution of V. dahliae is linked to segmental genome duplications mediated by improperly repaired DNA breaks.
Another talk which I found interesting was by Prof. Axel Brakhage from Leibniz Institute for Natural Product Research and Infect ion Biology ent i t led ‘Pathogenicity and Immune Evasion of the Human-Pathogenic fungus Aspergillus fumigatus‘. The study of virulence of A. fumigatus and Host-Pathogen Interactions is the one of the main topics in his lab. He demonstrated the main factors produced by the fungus to avoid recognition by resident macrophages. One is the hydrophobin protein RodA that masks essential molecular recognition patterns resulting in conidia being immunologically inert. Second, the conidia of A. fumigatus is covered by melanin DHN (dihydroxynaphtalene) and a strain with disruption of this gene showed attenuated virulence in a mouse infection model. It was also suggested that DHN inhibits the acidification step of phagolysosomes. A. fumigatus also produces a gliotoxin that has been shown to be important for virulence. Even though this talk was about human fungal pathogens, mechanisms of infection from plant and human fungal pathogens often overlap and similar approaches can be used to study both.
Prof. Gero Steinberg from University of Exeter talked about ‘Molecular motors in spatially organising the fungal cell wall’. His research aims to understand fungal pathogenicity and evolutionary conserved mechanisms of spatial organisation of eukaryotic cells. He had shown recently that in the pathogenic fungus Ustilago maydis early endosomes (EEs) have long-distance retrograde motility and this is necessary to trigger transcription of effectorencoding genes and secretion during host cell invasion. In his talk, he addressed the mechanism of peroxisome (PO) distribution in fungal cells. He shows that POs are evenly distributed in the cytoplasm. They show enhanced diffusion, which depends on the cytoskeleton. In addition, ~ 15% of POs move actively, which is driven by the motility of EEs.
I would like to thank BSPP by providing the opportunity to attend this event. Also, I would highly recommend the FEMS conference to anybody with an interest in advancing the understanding of current and future challenges in the study of microbiology and the next one will be held in Valencia, Spain in 2017!
Ana Karla Machado, Rothamsted Research
