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XV International Congress on Molecular Plant- Microbe Interactions, Kyoto, Japan 29th July – 2nd August 2012
Over 1000 plant pathologists converged on the city of Kyoto, Japan for the 15th International Congress on Molecular Plant-Microbe Interactions, one year later than originally scheduled because of the catastrophic 2011 tsunami. The Congress opened with the projection of an iconic image: a lone standing pine, against a blue sky background – a symbol of the resilience and survival against all odds. They call it the “Miracle Pine”, sole survivor of a wood destroyed by the unimaginable tsunami that devastated north-eastern coasts of Japan, killing tens of thousands and ravaging a country. The hosts urged us to remember and then move on. We came from over 40 countries. What followed over the next 5 days was an incredible introduction to the state of plant pathology in the genomic, transcriptomic and proteomic age, and it was fitting that the venue was a space-age international conference centre, and the location of the signing of the Kyoto Protocol on climate change.
The conference started with two one hour lectures, and as is becoming tradition the first by a distinguished guest from outside the society: arguably Japan’s leading immunologist S Akira taught us about the complexities of the mammalian innate immunological networks. The IS-MPMI Award this year went to Eva Kondorosi and, posthumously, to her husband Adam (poignantly on a day that would have been his birthday). Eva managed courageously to overcome the evident and understandably raw emotion and illustrate with beautiful images and deep science, the advances in our understanding of Rhizobium-legume interactions with a particular focus on host immunity and how the interplay controls the development of these fascinating nitrogen-fixing symbioses.
To come were four and a half intense days of lectures, discussions and a full immersion into the depths of our understanding and our ignorance of the events that unfold, and control the interactions between plants and environmental microbes. Interactions that can benefit or harm the partners, interactions which affect us, the users of plants as food, complex chemicals, materials and energy. The science is astounding, the advances awesome, at times the tension is palpable. One thousand scientists representing many more, come together to tell and learn, to show off and to argue, to discuss and laugh, to rekindle old friendships and forge new collaborations. Some old hacks evidently revelling in it all, many newcomers somewhat bewildered at times, perhaps overawed by meeting in the flesh, people whose names they associate with seminal discoveries and classic papers.
The humidity and heat hit you as you stepped outside at lunchtimes to devour bento boxes, but it felt rather pleasant by 8pm enjoying sushi next to the lake.
Over 600 posters were presented over two evenings. The BSPP was well represented with six members (Ian Toth, Pietro Spanu, Angela Feechan, Saskia Hogenhout, Anna Avrova and Rohan Lowe) invited to give talks and others presenting posters on different aspects of plant-pathogen interactions.
With 8 plenary sessions and 21 concurrent sessions, it was impossible to see it all, so what follows now are the thoughts of myself and fellow BSPP travel award recipients as to their favourite or most controversial sessions.
Anna Gordon National Institute of Agricultural Botany I was particularly taken with some of the fantastic visualisations as a result of confocal microscopy and labelling of pathogen proteins. For example, Peter Dodds presented GFP-labelled AvrM in the rust-wheat interaction, a secreted protein that is expressed in haustoria and is translocated into plant cells using an N-terminal signal sequence in a pathogen-independent manner. Barbara Valent presented evidence for a Biotrophic Interfacial Complex created when an invasive hyphae first comes into contact with a new host cell and across which Avr-GFP proteins are translocated into host cells. Weak GFP signals were also found in surrounding host cel ls , suggest ing protein movement via plasmodesmata. Arturo Genre presented great imaging of the amazing invaginations into plant cell membranes by arbuscular mychorrizal fungi labelled with GFP. Finally the in planta sexual hybridisation between two different Epichloe strains was presented by Daigo Takemoto using the combination of BemA and GFP to label hyphal tips to great effect.
Anna Avrova The James Hutton Institute I was very excited to see the first evidence of promoter involvement in protein localization presented by both Barbara Valent, whose group is working on the rice blast pathogen Magnaporthe oryzae and Maria Harrison, studying symbiot ic interac t ion between arbuscular mycorrhiza and Medicago truncatula. Chitin binding featured very prominently at this Congress with comparisons between pathogenic and symbiotic interactions. Several talks referred to the role of LysM domain proteins in different systems including a very detailed talk by Naoto Shibuya on the involvement of different chitin receptors in perception of both pathogens and symbionts. His group recently showed that a very limited mutation in the kinase domain of a cell surface receptor CERK1 could switch cellular responses from defence to symbiosis, indicating close evolutional relationships between these systems.
Wenbo Ma from Howard Judelson’s group in California presented an interesting data on Phytophthora RxLR effectors facilitating infection of Nicotiana benthamiana with both potato virus X or P. infestans by suppressing host RNA silencing through inhibition of the biogenesis of small RNAs. One of these effectors, PSR1, represents the first example of a non-viral pathogen effector able to suppress both microRNA and small interference RNA pathways.
Like all of us I am very thankful to the BSPP for the travel grant that allowed me to be part of this spectacular gathering of scientists interested in plant-microbe interactions.
Rohan Lowe University of Melbourne, Australia I enjoyed Kyoto 2012 as my first MPMI conference and it was a great opportunity to present my research on Leptosphaeria-Brassica interactions.
After a few sessions I was up to speed on the ubiquitous signalling acronyms and enjoying talks outside of my usual sphere. Yasin Dagdas presented a very comprehensive analysis of the role of septins in Magnapor the oryzae appressoria formation. I particularly enjoyed back-to-back presentations from Derek Lungberg and Paul Schulze- Lefert about similar work using massively-parallel sequencing to catalogue microbial communities in the Arabidopsis rhizosphere. Paul’s report of an unusual Rhizobia found in symbiosis wi th the Arabidopsis root was particularly notable. The role of chitin perception in plant-fungal interactions was a common theme across different sessions. My pick of the chitin-related presentations was Andrea Sanchez Vallet with an early report of a crystal structure for the Cladosporium LysM effector ECP6, a key example of the chitin-binding fungal LysMs. One of the most interesting points was their discovery of a second binding site in ECP6 with nano-molar affinity for chitin.
This super strong binding site came pre -loaded with chitin in their crystal structure, a product of the Pichia expression system. A mammalian system was required to produce a chitin -free version for full characterisation.
Overall I couldn’t fault the conference, easily one of the most well organised I have had the pleasure to attend and located in a city jam-packed with historical and cultural interest. I am very thankful to the BSPP for their generous support towards my travel expenses.
Jacqueline Monaghan The Sainsbury Laboratory How transmembrane receptor-like proteins, which contain an extracellular ligand-binding domain but lack an obvious intracellular signalling domain, manage to tranduce signals inside cells remains largely unknown. I was very excited to see work presented by Matthieu Joosten about a novel receptor -like kinase that interacts with several receptor-like proteins in tomato, including Cf4, and is required for resistance against fungal pathogens. In addition, intracellular components involved in signal relay from the plasma membrane leading to immune responses remains largely elusive for most immune pathways in plants. I thought that the phosphoproteomics approach presented by Hirofumi Nakagami to identify novel components involved in PAMP-triggered immunity was very promising. With the same goal, I recently conducted a forward genetics screen and am now mapping the mutations using a combined approach of positional cloning and whole genome re-sequencing. Being able to discuss my work with leading experts outside of my home institute proved to be an excellent opportunity, and helped to shape future projects. Not only that, but my international network has dramatically increased because of my attendance at the Congress. For these and other reasons, I am very thankful for the travel award I received from BSPP.
Angela Feechan CSIRO Plant Industry, South Australia The conference kicked off to a great start on the Sunday afternoon with six Special Workshops from imaging plantmicrobe interactions to proteomics. The powdery mildew workshop had some excellent talks and was very well attended. This included a very interesting talk by Carsten Pedersen, describing the similarities in structure of barley powdery mildew (Blumeria graminis f. sp. hordei) candidate effectors to RNAses and the possible evolution of effectors from RNAses was discussed. Pietro Spanu continued this fascinating theme in a later plenary session reporting that using a hostinduced gene silencing approach, some of these RNAase-like effectors were found to decrease the powdery mildew haustorial index in infected plants while others were found to suppress programmed cell death. Another development in the characterisation of powdery mi ldew ef fectors was presented by Ralf WeÃŸling. Using a yeast-two hybrid screen with predicted Golovinomyces orontii effectors this study found that these effectors target predominantly nuclear, chloroplast and cytosolic targets respectively. Many of these nuclear targets were transcription factors, which are also targeted by the effectors of unrelated pathogens including the bacterial pathogen Psuedomonas syringae and the oomycete pathogen Hylanoperonospora parasitica. These signalling targets were described as hubs for effectors to target. This was later discussed by Roger Wise who had found genes controlled by the barley powdery mildew resistance gene MLA. Not only was the science terrific but there was also time to enjoy Kyoto culture from stunning Buddhist temples and Shinto shrines to tasty tempura, sushi and of course sake. A big thank you to the BSPP for supporting my conference attendance through the travel grant.
Pietro Spanu Imperial College of Science, Technology and Medicine In fact, much like the Olympics from which I gratefully fled, the real activities had started earlier: a full Sunday afternoon of exciting “special workshops” in 2-by-3 parallel sessions setting the tone as an appetizer to the main course. Concurrent sessions are always a disappointment: one all too often seems to want to be elsewhere at the same time. Imaging, Induced Susceptibility or Powdery Mildews? Rice Immunity, Functional Genomics of Bacteria or Proteomics? For this attendee at least, the first was a nonchoice: I co-chaired the Mildew workshop.
What were the highlights? Perhaps this year there was not a single headline discovery towering above all others.
There did not seem to be a new technique or technology which the leading groups vied to show off. The impression was more one of integration, of solid advance, of deeper understanding. It seems to me, as a biased observer, that networks were the leitmotiv of the meeting, perhaps in an understated manner. Gone are the days of the single-gene-and-pathway.
Even where the projects focussed on non-systems approaches, the resulting picture from the ensemble is a complex symphony of signals emitted and perceived, interfering, stimulating, suppressing. Effectors, receptors, interactors, compartments, targets and outputs playing together in a dynamic balance of life and interactions, that are inevitably at the heart of our work.
Microbes which interact with plants exploit all known (and probably many of the unknown) pathways their hosts use in development and immunity. The result of hundreds of millions of years of evolution, the dynamic crosstalk, the tension inherent in both competitive, deleterious pathologies and cooperative beneficial symbioses are now becoming clear. And with this understanding comes the promise of improved crops, greater security in our food and energy sources even if, honestly, these matters are still rather remote from the inevitable lip-service paid by speakers and poster presenters alike, in what is still a “fundamental science” (i. e. nonapplied) meeting.
Having said this, to me the highlights of the meeting were the twin talks on the common pathways controlling both rhizobial and mycorrhizal symbiosis by Giles Oldroyd and Martin Parniske. This, per se, is not a new discovery: the existence of mutations that affect both interactions has been known for years.
But the exquisite molecular details of these are now becoming clear. So much so, that the dream of re-creating nitrogen fixing symbiosis in central crops like the cereals seems to come in to focus even for those working outside that field. The goal of N-fixing nodules on rice or wheat seems attainable.
Perhaps 20 years off, but still no longer science fiction. This pinnacle of synthetic plant biology could actually be achieved in our lifetime, one signalling step at a time. I wonder, though, what we are going to do about the inevitable requirement for P-fertiliser to feed the new supercrops.
One thing struck me: how many references there were to the flg22 and its receptor FLS2. The days in which research into “non-specific elicitors” was generally regarded by many gene-forgene practitioners as essentially irrelevant to pathology feel now as distant as the days in which we though the world was flat and that you’d fall of the edge if you sailed far enough west of Gibraltar. PTI and ETI, the (now less fashionable) zig-zag-zig model, the guard and decoy hypotheses , integration of surface, cytoplasmic and nuclear based reception of microbial signals have all but eclipsed those days.
The biology of chitin receptors, suppressors as factors essential for basic compatibility and disease are now as mainstream as the myriad of NBSLRR proteins. Any controversies? What is the true nature of the RXLR motif and its role in effector uptake? What are the mildew avirulence genes? How does AvrRPS2 really work? These are just a few that are close to my interests. Still much to do and keep us busy in years to come. The 18th Congress of the International Society for Mushroom Science, Beijing, China 26th – 30th August 2012 China is the largest producer of mushrooms in the world, accounting for somewhere in the region of 60-80% of total world production. Although many other mushroom conferences have been held in China, this is the first time that the ISMS congress was hosted by China.
Mushroom production in China has tripled in the last 10 years, from 7 million tonnes in 2001 to 21 million tonnes in 2010 – a phenomenal growth achievement by any standard. There are over 20 mushroom research centres in China and in the region of 1000 mushroom scientists. I was very impressed with the many mushroom research students who provided help and assistance throughout the congress; they were young, enthusiastic, dynamic and fluent in English. It was fitting therefore that the 18th ISMS congress was held in Beijing, in order for mushroom scientists worldwide to appreciate the scale of investment in mushroom science and technology that has occurred in China in the last 10 years.
There were a total of 1132 delegates at the conference from 65 countries and in addition, 69 mushroom-related companies exhibited at the Trade show which ran throughout the conference. The conference was dominated by Chinese delegates, scientists and companies highlighting the vibrancy and professionalism of the expanding Chinese mushroom industry.
My interest was focused on the pest and disease sessions which dealt with P&D issues of Agaricus bisporus and also of the many other cultivated species of mushrooms that are more popular in Asian countries. Four papers addressed Trichoderma agressivum in Agaricus bisporus production, a competitor mould that continues to affect mushroom production in the USA, Canada and Europe but which has not yet been encountered in China. Johan Baars presented one of the most interesting papers reporting that T. agressivum infections in compost may be detectable at an early stage due to novel volatiles being produced during the infection period. This may lead to a new volatilebased diagnostic test for the industry which would give an early indication of the presence of this problem fungus in mushroom compost.
As a pathologist, it was great to hear several papers giving details of the many diseases associated with a wide variety of cultivated mushroom species that we do not grow in Europe. The most widely cultivated species in China include Pleurotus ostreatus, Lentinula edodes (Shitake), Auricularia auricular (Wood ear), Flammulina velutipes (Enoki), while production of many other new and interesting species – such as Pleurotus eryngii (King Oyster), Clitocybe maxima, Coprinus comatus, Tremella fuciformis (White jelly leaf fungus) – is increasing. All are susceptible to different pathogens although some pathogens affect many species (e.g. Pseudomonas tolassii causing blotch diseases and Trichoderma spp. causing substrate -rot problems. Yinbing Bian indicated that there were 20 common mushroom diseases which included a few associated with Agaricus bisporus but of particular interest to me was to hear about a serious new disease of Auricularia polytricha, called “slippery scar disease” caused by Scytalidium lignicola.
Several papers also looked at potential biological control agents for use in mushroom production, given the continued withdrawal of pesticide products for use in mushroom cultivation. Of particular interest was promising data from Thierry Regnier on the potential of thyme oil to control both fungal diseases and mushroom flies. Another interesting paper was presented by Weihong Peng on the cultivation of Tremella fuciformis (White jelly-leaf fungus). The white gelatinous fruitbody is actually a dual culture where Tremella fuciformis has parasitized a host fungus, both of which are present on a woody substrate.
Research has indicated that the host fungi in the wild can vary widely but that the best commercial production is obtained with Annulohypoxylon stygium as the host species. Consequently modern commercial cultivation of this mushroom in China uses selected strains of both T. fuciformis and A. stygium, which are both inoculated into a sawdust-based substrate.
The congress also had very interesting sessions on “Genetics and Breeding”, “Germplasm Diversity” and “Nutritional and Medicinal Aspects” and all were dominated by Asian scientists. Mushrooms have many beneficial health and medicinal properties which are being “rediscovered” by the West; however they have long been revered in China where mushrooms have a long tradition of cultivation, consumption and medicinal use. A demonstration farm was built just outside Beijing in 2007 and a Mushroom Exhibition Centre was built alongside it to coincide with the Congress.
A day trip to both was included in the conference program and it was amazing to see so many different species being cultivated and to read about the rich mushroom culture and tradition that has existed in China over the centuries.
Needless to say mushrooms featured widely on the menus both at the conference and also in local restaurants.
In conclusion, I would like to thank BSPP for the travel grant to enable me to attend this very interesting congress.
It was a great experience and has opened up many avenues for collaboration with mushroom scientists from around the world into the future.
Dr Helen Grogan Teagasc (Agriculture and Food Development Authority), Ireland