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The 25th Fungal Genetics Conference at Asilomar, California, March 17-22 2009
The 25th Fungal Genetics Conference, organised by the Genetics Society of America, took place at the Asilomar Conference Grounds in Pacific Grove on the Californian coast. This was a wonderful location, with the Asilomar State Beach just minutes away from the heavily wooded and quiet atmosphere of the Grounds, which were founded in 1913 and have played host to the conference for a number of years. In total, there were 946 participants and over 650 posters making this rather a large event! We were fortunate enough to have great weather, perhaps too good owing to the number of delegates suffering from a touch of sunburn (myself included!).
The conference took place over four days, with plenary talks in the morning, concurrent sessions in the late afternoons and posters in the evenings.
In addition, Ad Hoc sessions, on topics such as genome annotation, and a number of taxa-specific workshops took place during the midday break. A wide range of subjects were covered over the course of the conference, such as hostpathogen interactions, metabolism, comparative genomics, evolutionary genetics and gene regulation. The talks and posters presented were of a very high quality and the science was highly interesting and relevant.
Patrick Keeling (University of British Columbia) began the first plenary session with a fascinating talk about microsporidia, a group of fungal-related obligate parasites of animals. These organisms possess very tiny genomes about half the size of that of E. coli, and as such appear to lack a number of key genes found in most other organisms.
In one of the most extreme cases, Enterocytozoon bieneusi, a common pathogen of humans, lacks genes encoding the enzymes of glycolysis and so obtains ATP from the host cell by sequestering the host’s mitochondria around itself so that it can obtain ATP directly from them!
Other talks ranged from a discussion of the dandruff-associated fungus Malassezia globosa obtaining lipids from its host to compensate for its lack of fatty acid synthase (Charlie Saunders, Proctor and Gamble, USA) to Bruce McDonald’s (ETH Zurich, Switzerland) work on the evolutionary origin of the plant pathogenic Septoria species which appear to have diversified around the time of agricultural intensification several thousand years ago. The secondary metabolism concurrent session included talks on the role of toxin production in infection by the pine pathogen Dothistroma septosporum by Rosie Bradshaw (Massey, New Zealand) and SMURF, a web tool for genomic mapping of secondary metabolite clusters by Natalie Fedorova (J. Craig Venter Institute, USA).
The poster sessions provided a great opportunity to discuss ideas with members of other groups and I found out a large amount of useful information from sharing ideas. It also allowed me to present and discuss my work to a large international audience and I was very pleased by the number of people who came to talk about my poster. The next three days followed a similar format and from the large number of stimulating talks containing much novel and unpublished material, only a selection can be discussed here. Brett Tyler (Virginia State, USA) and Pieter van West (University of Aberdeen) revealed some fascinating information about the mechanism of effector protein entry into host cells via the use of the oomycete-identified RXLR motifs to bind host lipids and subsequent apparent uptake via endocytosis. Brett also showed the presence of an RXLR motif variant found in fungal effector proteins and a conservation of function between the oomycete RXLR motif and the PEXEL motif found in effectors of the malaria pathogen Plasmodium.
Magnaporthe oryzae is the causal agent of rice blast disease and an important agricultural pathogen. Sarah Gurr’s (University of Oxford) talk included a discussion of the role of the cutinase Cut2 protein in this disease. M. oryzae enters rice leaves via the formation of a high-pressure infection structure known as an appressorium, which produces an infection peg that punctures the leaf surface. In mutants lacking CUT2, virulence was greatly reduced due to an impaired penetration of the leaf. Cut2 was found to be an upstream activator of both the cAMP/PKA and PKC pathways which are involved in signalling for successful plant infection.
Cut2 therefore appears to play a role in surface sensing that leads to entry into the host leaf. Nick Talbot (University of Exeter), meanwhile, focussed on NADPH oxidases, of which M. oryzae has three homologues. Two (Nox1 and Nox2) are required for pathogenicity, being involved in appressorium formation and host entry, while the third (Nox3) is linked to sporulation and growth.
Bob Proctor (USDA) described a Fusarium species where additional genes were present in the main toxin biosynthetic cluster. In other species these genes, which are also involved in production of the toxin, are normally found elsewhere in the genome and through phylogenetic work, are suggested to have moved into the cluster in this species, rather than out of the cluster in others. Bob went on to show that the evolutionary relationships of the toxin biosynthesis genes was not always congruent with that of housekeeping genes and this could be the result of trans-species polymorphism, whereby descendent species inherit different alleles from an ancestor in a way that doesn’t reflect the phylogeny.
My Rothamsted Research colleague Rohan Lowe presented his work on metabolomics analyses of Fusarium species, as related to their production of the important toxin deoxynivalenol (DON). Rohan’s talk went very well and he showed how the 1H-NMR techniques could be used to distinguish isolates and growth conditions based on metabolome datasets.
Richard Oliver’s (Murdoch, Australia) talk revealed new insights from comparative genomics of dothidiomycete species, outlining a new type of synteny described as mesosynteny. In this case, the gene content of a scaffold or chromosome is conserved between different species yet the gene order is altered, meaning that only intra-chromosomal (or intrascaffold) translocations have occurred.
This phenomenon may help to protect against chromosome loss.
I was fortunate enough to be able to present my work with a talk at the Fusarium workshop. This was a very informative morning and a useful gathering for the community. I was pleased with how my talk went and enjoyed my first opportunity to speak at an international conference.
I would like to thank the BSPP for their generous contribution towards the cost of my attendance at the 25th FGC. I would also like to thank my supervisor Kim Hammond-Kosack and the Fusarium workshop organiser Bob Proctor for the opportunity to speak at the conference. This was a great opportunity to interact with the global fungal community, discuss ideas and find out more about other projects. In addition I was able to discuss my own work with others and gain useful information to help me as I finish my project.
Andrew Beacham, Rothamsted Research The biennial meeting at Asilomar (California, USA) is a major event on the calendar of fungal genetics researchers and those using associated techniques. It attracts a global audience and this year the capacity was extended to around 950 for the first time, after past over subscription of the event.
Despite the conference being founded in pure genetics and non-pathogenic organisms such as Neurospora crassa, registrants from the plant pathogen community have increased and this year formed a large proportion of attendees. The conference isn’t strictly fungal and includes Oomycetes and other non-fungal organisms, much to the benefit of the meeting.
The session on metabolomics and proteomics was of particular interest to me as I was selected to give a presentation of my work on using metabolomics to study Fusarium fungi.
I would have struggled to make it to the conference without a BSPP travel grant, and thanks to their support I was able to present my work at the most suitable venue. Two other talks in the session were of particular interest. Philippe Tanguay reported the use of proteomics to improve the annotation of the genome sequence for Melampsora larici-populina, a poplar leaf rust fungus. This fungus is an obligate pathogen, and so an LCMS-MS approach was taken to detect peptides derived from uredospores, the most easily accessible tissue from the pathogen. Despite the limitations of the system, a small scale experiment resulted in validation of over 1600 gene calls, modified gene models for 99 and identified 73 novel genes. Informal discussions at the coffee break indicated that EST-supported gene calls cannot reliably predict N and C termini of the resultant proteins, with the N terminus most problematic. Massspectroscopy based proteomics methods look like being an efficient way to define these regions and improve the quality of genome annotations.
Following Philippe was a former colleague of mine, Kar-Chun Tan. He reported the use of both proteomics and metabolomics to dissect signal transduction and pathogenicity in Stagonospora nodorum, a necrotrophic pathogen of wheat. He presented a nice piece of work showing how a proteomics approach coupled with some targeted gene knockouts identified a short chain dehydrogenase (Sch1) that is required for asexual sporulation. A non-targeted metabolomics approach was used to characterise the sch1 mutant and subsequent ly the overproduction of the mycotoxin alternariol was identified in the mutant.
It was nice to see two ‘omics techniques being used to effectively guide and extend reverse-genetics experiments.
Of special interest to me were the factors which result in fungi synthesising secondary metabolites.
There were several reports on factors affecting the production of the trichothecene mycotoxin deoxynivalenol (DON). DON is a serious problem in cereal crops. For example, Fusarium ear blight of wheat will result in lowered grain yields that are great ly compounded by the introduction of mycotoxins, which spoil a much larger proportion of the harvest. Much progress on the fungal side of things has been made over the years, including the identification of a cluster of genes required for the synthesis of the toxin. However, the early events that lead to activation of the gene cluster are not so well known. Donald Gardiner from CSIRO (Brisbane, Australia) reported that when Fusarium graminearum is grown in culture with certain polyamines (such as agmatine or putrescine) as the sole nitrogen sour ce, this resul ts in rapid accumulation of DON to extremely high concentrations. Such a powerful and defined inducer has not been reported previously, and this mechanism could lead to increased understanding of signals in the wheat ear that induce DON synthesis.
On a more general note, although I failed to hear his talk, Brett Tyler’s report on a host lipid-dependant mechanism for cell entry by Oomycete RXLR effector proteins resulted in much discussion afterwards. In addition to a mode of entry, he reported that in fact bo th Oomy ce te ef fec tor s and Plasmodium effectors (using the PEXEL motif) can utilise a similar family of host lipids to gain entry to their various hosts. This was pretty big news and will surely turn up in press soon in a high impact publication as well as at the ISMPMI conference this summer in Quebec.
Overall, it was an excellent conference that included some very interesting presentations and has definitely helped me advance my work by incorporating new ideas passed on by fellow researchers.
Rohan Lowe, Rothamsted Research
