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The 21st International Conference on Arabidopsis Research, Yokohama, Japan June 6-10, 2010
Following an 11 hour flight to Tokyo airport and a further 2 hour drive I arrived at the Pacifico Yokohama Convention Centre, the venue for the 21st International Conference on Arabidopsis Research (Co-chaired by Kazuo Shinozaki and Kiyotaka Okada).
Located along the centre of the recently renovated new Yokohama beach, this setting provided an enchanting atmosphere throughout the conference.
The international Arabidopsis conference is the largest and most prestigious annual conference for plant scientists. More than 1,300 members from numerous academic institutions located throughout the world were in attendance. The aim is to share knowledge and understanding of current cutting edge research on a vast range of plant species, from the model plant Arabidopsis thaliana to economically important crop varieties.
At any given time there are eight concurrent sessions and plenary talks, with 800 research posters on display.
Both provide great opportunity to view and discuss different approaches and perspective of research.
During the course of the conference I was attracted to several immensely interesting talks summarised below.
Such is the technological and scientific advance during recent years that much of this work would not have been possible without high throughput next generation sequencing technology.
Steve A. Kay, University of California
The circadian networks were considered to be regulated with relatively simple components. However recent work combining forward genetics with cellbased assays (luciferase fusion system) and whole genome transcriptome approaches by Steve A. Kay (University of California, San Diego, USA) discovered that circadian clocks of plants are composed not of a single auto-regulatory loop or limited cycle, but rather of multiple positive and negative interlocking feedback loops.
Interestingly the B-box protein family appears to perform a central role in circadian signalling.
David Baulcombe, University of Cambridge Small non coding RNAs are commonly referred to as the dark matter of genetics! However the David Baulcombe lab (University of Cambridge, UK) has recently described much more dynamic roles – from being negative regulators of gene expression to participation in more complex regulatory systems involving chromatin. Interestingly it was found using a grafting experiment approach that small RNAs can move from stem to root and act as part of an RNA signal.
Ken Shirasu, RIKEN Plant Science Centre The Ken Shirasu lab (RIKEN Plant Science Centre, Japan) introduced several interesting research topics relating to flagellin-induced small open reading frames (sORFs) and the biological chemistry in understanding hypersensitive cell death in Arabidopsis.
In Arabidopsis thaliana, at least 3000 ORFs are predicted to be novel protein coding genes. The Shirasu lab introduced a custom microarray approach to compare the expression of ~6000 unannotated sORFs in Arabidopsis Col-0 with the flagellin insensitive mutant fls2, following treatment with the defence inducer (PAMP) flg22. Based on their expression profiles and homology with plant proteins this identified 14 candidate ORFs. Currently they are generating overexpressor lines to analyse the candidate sORFs in PAMP-triggered immunity and plant defence. This pioneering approach has paved the way to identify the role of sORFs and perhaps help identify missing components in the defence signalling pathway.
In addition, their biological chemistry approach to investigate Arabidopsis R (resistance)-gene mediated defence responses to bacterial pathogens was also very interesting. They have established a high-throughput quantitative assays system for HR (hypersensitive response) cell death, an indicator of defence responses, by using Arabidopsis suspension cells.
Seven compounds that potentiate HR in a concentration dependent manner were identified from the screening of a commercial library of 10,000 diverse chemicals. They further grouped those potentiators into 3 categories based on their mode of action such as activation of SA biosynthesis, SA mimics, and inhibition of the SA inactivating pathway. Their spectrophotometric determination of Evans blue-dyed cell for cell death quantification enabled a high-throughput screening system by using a 96-deep well plate.
Seung Yon Rhee, Carnegie Institution for Science In an evolving systems and computational biology era there remains the challenge to integrate metabolomics, metabolic network and gene function network for systematic gene function identification.
Seung Yon Rhee (Carnegie Institution for Science, Arabidopsis Metabolomics Consortium, USA) presented a systematic approach by combining computational modelling, genetic and metabolomics approaches coupled with literature curation. By using over 24 datasets (“omics”) from functional genomics experiments in plant and animal model organisms this team was able to produce a genome-wide functional association network of Arabidopsis genes. This network, called AraNet has been used to predict candidate genes involved in small molecule metabolism using well characterized genes involved in specific metabolic pathways as bait. Knock-out mutants of predicted candidate genes were subjected to metabolite profiling on 11 analytical platforms, which have the combined ability to generate relative abundant data of nearly 3100 Arabidopsis metabolites/analytes.
Identified metabolites that were significantly altered in these mutants were used to delineate reactions and domains of the metabolic network that are significantly altered by using AraCyc, a metabolic network of Arabidopsis that has been curated with experimental information from the literature.
Beside the talks and poster sessions, there were 6 different workshops and many other exhibition booths.
Workshop on ‘Plant Senescence and the Associated Cell Death’ (organised by Hong Gil Nam and Pyung Ok Lim) seemed a very interesting systems biology approach to understand leaf senescence.
Overall, it was an excellent conference for both science and social networking with many other international scientists present. However, it was a little surprising that there were no talks or posters (apart from mine) related to nitric oxide- and/or nitrosothiol mediated signalling in plant immunity which has recently emerged as a key regulator in both defence and hypersensitive cell death during the plant disease resistance response.
I would like to take this opportunity to extend my grateful appreciation to BSPP for facilitating my attendance at this most excellent conference through the generous travel award. Thank you!
Byung-Wook Yun University of Edinburgh, Edinburgh UK
The impressive convention centre in the recently designed Minato-mirai area of Yokohama welcomed about 1300 attendees to the 21st International Conference on Arabidopsis Research (ICAR). At a time when the plant biology scientific community is unsure about the potential of the knowledge derived from Arabidopsis research in understanding general plant biology and in industrial applications, the Japanese style futuristic environment at ICAR seemed perfect scenery for fruitful and inspiring talks.
In the first plenary session, Peter McCourt from the University of Toronto presented the audience with what would be a frequently discussed research approach at the conference: based on the premise that proteins of coexpressed genes more often interact with each other to signal, computational models are being developed in a systems biology context to investigate functional hypotheses of signalling pathways. McCourt’s work on abscisic acid (ABA) signalling showed a complex interactome where known and unknown proteins signal and respond to each other, allowing the identification of new components of this pathway. Coming from Kyoto University, Ikuko Hara-Nishimura is investigating plant defence strategies. He provided evidence of an exciting novel membrane fusion mediated defence mechanism, where the fusion of membranes of a large central-vacuole with the plasma membrane results in the discharge of vacuolar antibacterial proteins to the extracellular environment, inhibiting the proliferation of bacterial pathogens.
In a global warming context, Koh Iba from Kyushu University is looking at how the guard cells control the stomatal apertures and the levels of CO2 exchange between the plants and the atmosphere. By taking advantage of a clever thermal imaging screen he isolated temperature mutants impaired in the opening, closure or movement of stomata in high and low CO2 concentrations, having identified CDI3 as a guard cell plasma membrane localized protein whose mutant is insensitive to the carbon dioxide concentrations. Joseph Ecker from the USA Salk Institute presented his work on parallel analysis of nucleic acid populations taking advantage of the ever emerging DNA sequencing technologies. The applications to which these technologies are currently being applied include, for instance, the sequencing of genomes to identify nucleotide polymorphisms, structural variation, DNA-protein interaction and cytosine methylation sites. Ecker found that different natural variations of Arabidopsis present distinct epigenomes with different methylation degrees, and different tissues showed variations in the cytosine methylation levels as well.
Interestingly, snRNA and mRNA methylation levels showed to be reduced by salicylic acid, linking stress signalling to cytosine methylation.
The concurrent sessions in the afternoons included diversified and wonderful talks on topics like regeneration, systems biology and metabolism, developmental regulation, or novel function of peptides in intercellular signalling. Following his recent Nature publication, work on organ regeneration was presented by Kenneth Birnbaum from New York University. According to past experiments, it is widely accepted that undifferentiated cells in the meristematic region are necessary for regeneration of plant organs.
Experiments conducted by Birnbaum revealed that the excision of root tip regions resulting in the complete removal of the quiescent centre, a stem cell niche in the meristematic area, did not stop the regeneration of the root tip. Using markers that were highly enriched in specific cell types, cell-type specific transcriptional analyses showed that the molecular recovery of the excised cells identities began within five hours after cutting, indicating a rapid re-specification of lost cell fates. These exciting results allow the identification of new candidate regulators for specification of cell identity. Also, blocking auxin transport led to failure in regeneration, suggesting that auxin, which has been shown to form a potentially constructive concentration gradient, may be critically involved in the organogenesis process.
A smart high throughput analysis system is being used by Wolf Frommer from the Carnegie Institution for Science to investigate the Arabidopsis plasma membrane protein interactome and its interface with signalling proteins. The mating-based split ubiquitin system (mbSUS) is based on the release of an artificial membrane bound transcription factor from the membrane if two membrane proteins interact, activating the expression of marker genes. Hundreds of membrane protein interactions have already been identified employing this method.
To end the conference in style, a banquet mixing the delicious Japanese cuisine with western food was followed by a live performance of Japanese drummers, in an impressive combination of powerful sound and light agility. For the opportunity to attend this most interesting and very well organised conference, as well as the chance to visit Japan and have sushi everyday, I sincerely thank BSPP for giving me the Travel Award.
Luis Carraca, Imperial College, London
The 43rd Brazilian Phytopathology Congress, (15-19 August, 2010) in Cuiabá, Mata Grosso, Brazil Last year I received an invitation from Dr Claudio Marcelo Goncalves de Oliveira (Instituto Biologico, Brazil) to present a paper at the 43rd Brazilian Phytopathology Congress, (15-19 August, 2010) in Cuiabá, Mata Grosso, Brazil and to visit several universities and research centres. Without hesitation I accepted and with support from the BSPP I was able to undertake this visit.
In the four decades since meetings of the Brazilian Phytopathology Congress were initiated, agriculture in Brazil has been transformed. It has the fourth largest agricultural system in the world, after China, the United States and Europe, it is one of the world’s most productive agricultural regions and Brazil is now virtually self-sufficient in food. Brazil is the world’s biggest producer of coffee, oranges and sugar cane and the second largest grower of soybean, and the third for corn. It has become a major exporter (25% of produce is exported) and its exports are expected to continue to increase rivaling its competitors and probably surpassing them in the future. The OECD predicts that Brazil will have by far the fastest growth of agricultural production worldwide in the next ten years, exceeding 40%; twice the world average. Brazil is seen as a major contributor to meeting the future food needs of the growing world population with its abundant supplies of water and arable land, and is expected to provide an increasing proportion of agricultural commodities to China, India and the rest of the developing as well as a source of agricultural expertise in tropical agriculture.
The development of agriculture in Brazil is attributed to innovative government programs which supported agricultural research, capital-intensive large farms, an openness to trade and to new farming techniques. Support for agricultural research was formalised in the mid-1970s, with the establishment of the Embrapa research organisation which has underpinned the adoption of new technologies including genetically modified crops, the use of agrichemicals and investment in farm mechanisation.
Agribusiness now plays a central role in Brazil’s economic development, and accounts for >25% of the nation’s GDP, 35 percent of its workforce and 35 percent of its export dollars and is a major driver of social and environmental change. The rapid growth in agro-production in Brazil has also generated skill shortages and opportunities for employment in this sector. This was very evident at the Phytopathology Congress with the remarkable numbers of graduate students in attendance (approximately 1200 students). This brought a refreshing youthful, social and positive atmosphere to the meeting.
The 43rd Brazilian Phytopathology Congress organised by the Brazilian Phytopathology Society, Embrapa, UFMT (Federal University of Mato Grosso), IFMT (Federal Institute of Education, Science and Technology of Mato Grosso) was held in Cuiabá, Mata Grosso in western Brazil. This state is the major producer of soybeans in Brazil, as well as sugar cane and cotton and it has vast cattle ranches.
Agriculture is a major part of the economy of this state. Mata Grosso is also home to the Pantanal, an extensive floodplain which is a spectacular region for watching wildlife, and it also extends to the Amazon rain forest in the north.
The state is rapidly changing as only 30 years ago most of the State was Mato (jungle forest) or Cerrado (savannah brush) with few roads that go into the dense tropical forest. At the time of the meeting it was hot and dry and the sky was hazy from dust, smoke and pollution and this added to the “frontier” feeling and fitted well with my invitation to talk in a session about taxonomy and the use of molecular diagnostics.
The opening talk of the congress was by Prof Alexander Karasav from the University of Idaho “Genetic diversity of Potato virus Y: a new challenge for plant quarantine services”. He clearly described the limitations of both genetic screens and molecular methods to define virus strains of PVY and discussed the challenges of merging this information. Neither molecular nor genetic methods are sufficient for fully predicting the behaviour of current virus strains on different potato genotypes and new recombinants as they arise.
The lecture by Prof John Lucas (Rothamsted Research) gave an overview of integrated management of fungal diseases of wheat in UK production systems. Wheat yields in the UK and other parts of Western Europe are of the highest. A synthesis of information acquired over decades on climatic conditions, disease pressure, crop history and inputs including chemical applications all contribute to the development of integrated management of fungal diseases of wheat and the generation of high yields.
The yields of wheat in Brazil are much lower than in the UK put presumably could be greatly improved. The talk that stood out for me at this meeting was by Prof Pedro Crous, Director of the CBS Fungal Biodiversity Centre, the Netherlands on “Classic taxonomy and molecular phylogeny of plant pathogenic fungi”. The message he conveyed is the potential for massive under representation of fungal diversity using classic culture methods that favour particular isolates and that there are great numbers of undescribed species of fungi. The lack of morphological features to distinguish many fungi is problematic. However new sequencing technologies which are highly sensitive and less biased are providing powerful new tools that are revealing far greater diversity that previously realised. Prof Crous also described the capability for aerial dispersal of fungal spores and the need to develop new methods of identification and detection. Defining molecular targets for identification is still under discussion in the fungal community and more than one target is likely to be required as ITS comparisons do not work for many groups. Several international consortia have now received major funding for bar-coding projects and fungal taxonomy in the future is likely to be transformed with the combination of expertise in bioinformatics, morphology, molecular biology and biology.
The Nematology session in which I spoke included three talks followed by a discussion. Prof Ailton Rocha Monteiro (ESALQ/USP) introduced the session with a review of the uses of classical taxonomy for identification of nematodes in Brazil of agricultural importance. The talk by Dr Claudio Marcelo Goncalves de Oliveira (Instituto Biologico) considered how both classical morphology and molecular methods were of use in resolving problems in the taxonomy of nematodes. I had been asked to discuss the application of molecular diagnostics to plant parasitic nematodes and gave examples that demonstrated how high-throughput molecular diagnostics can cope with large numbers of samples that previously would have required visual inspection, and quantitative PCR provides an experimental tool to study population dynamics of species mixtures which previously would not have been feasible. In the future molecular diagnostics is likely to provide tools for distinguishing pathotypes which are morphologically indistinguishable. The talks and posters were mainly in Portuguese which limited how much I gleaned from them but in general they were oriented towards addressing practical phytopathological problems. Developing alternatives to agrichemicals was a common theme amongst the posters using different soil amendments and biocontrol agents, anticipating the changes in disease management in the future. Also, the scientific program included important scientific topics that are currently investigated in the Brazilian Nematology including taxonomy, host-parasite interactions and crop rotation as an alternative to nematode control.
After the congress I had an opportunity to visit several other research centers and universities. The Experimental Centre of the Insituto Biologico in Campinas, Sao Paulo state, where Dr Claudio Marcelo Goncalves de Oliveira is based, is dedicated to research and extension in the following areas: Plant Pathogenic Bacteria, Plant Pathogenic Fungi, Agricultural Nematology, Biological Control, Entomology, Weed Science, Acarology and Clinics for Diagnostic of Plant Diseases. Here I gave a lecture to researchers, postgraduate and undergraduate students, met students undertaking Nematology projects, and visited the Nematology, Bacteriology and Biocontrol laboratories. The next day we traveled inland to the Campus of the University of Paulista, Botucatu to the lab of Dr Silvia Wilcken who specializes in the identification and control of Meloidogyne spp. in golf grass and horticultural plants, and the lab of Dr.
Edivaldo Domingues Velini who is using HPLC/MS to study the effects of low glyphosate doses on growth of a range of plant species. At the Coffee Centre at Instituto Agronomico, Campinas we visited the molecular lab of Dr Miriam Maluf who is working with the coffee breeders using molecular markers to assist with the identification of new varieties and Dr. Wallace Gonsalves showed us the screening program for identifying nematode resistance in coffee progeny. This was followed by a visit to a coffee plantation at Bragansa Paulista which has a significant amount of infection from Meloidogyne exigua and they are using cultural methods such as applying organic matter to manage yield losses. The final lecture was given at the University of Sao Paulo in Piracicaba to postgraduate students from the Plant Pathology course and members of staff from the Luiz de Queiroz College of Agriculture (ESALQ).
The two weeks I spent in Brazil provided me with an excellent opportunity to become acquainted with some of the nematological problems in Brazil. The most common problems were with root-knot nematodes which tend to have wide host ranges, rapid multiplication rates and prefer topical climates. It was encouraging to see that the need to find alternatives to chemical methods was recognized as was the importance of sustainable production of existing arable crops so that remaining natural habitats and the huge diversity of species are preserved. Brazil has quickly become one of the main agricultural producers on a global scale and this has brought both practical and scientific challenges which will continue as Brazil seeks to develop its potential in the future.
Vivian Blok, SCRI 2nd International “Erwinia” Workshop, Isle de la Reunion and 12th International Conference on Plant Pathogenic Bacteria On 5-6th June the second International Erwinia Workshop (IEW) was help prior to the ICPPB in Reunion (the first workshop was in Dundee, Scotland in 2006), and was organised by members of the University of Pretoria and chaired by Ian Toth (SCRI). The meeting consisted of a number of talks and posters from many of the main groups world-wide working on the enterobacterial plant pathogens. This year also saw the inclusion of work by Robert Jackson (Reading University) on the interactions between human enteric pathogens and plants – an area that we hope will become an important part of the IEW in future. It became clear very quickly that many things have changed in this field since the last meeting.
There are now many more genome sequences for the enterobacterial plant pathogens than the 2-3 available in 2006 and these were being successfully exploited in a number of areas, including diagnostics, pathogenesis and epidemiology. New disease problems that had emerged over the last few years were discussed, including Dickeya spp. on potato in Europe and Pantoea ananatis of eucalyptus in South Africa.
These issues had led to the development of improved diagnostics and typing methods to monitor and track populations, as well as new insights into the pathogenesis and other lifestyle determinants of these pathogens. We heard about interesting new findings on the regulation of pathogenicity and the role of recently identified pathogenicity determinants (such as the Type VI secretion system) in disease development. There were also some exciting new findings in more applied research, with Jacquie van der Walls discussing how research can be applied directly to solving industry problems. Other presentations discussed statutory matters. It was recognised at the end of the meeting that this group offers a wide range of expertise on the enterobacterial plant pathogens and their interactions with plants (which we hope to exploit more to investigate human pathogen-plant interactions). This expertise includes strategic through to applied research and statutory knowledge, and there was a keen interest to continue to hold the IEW in future years.
Conference Day 1: Genomics and Evolution On Monday 7 June, the 12th ICPPB conference was kicked off. We were welcomed by the organizing committee and by members of INRA and CIRAD to the beautiful island of Reunion.
Monday’s session dealt with the topics of genomics and evolution. Four years earlier the ICPPB meeting in Edinburgh saw the discussion in two talks of the first genome sequences. One of the key aspects of the 12th conference was the evolutionary strides made since then in the field of genomics, with no less than nine talks on the first day discussing the genome sequencing of a broad spectrum of plant pathogenic bacteria from a wide range of genera, including Pseudomonas, Erwinia, Pantoea, Ralstonia, Pectobacterium and Xanthomonas. What can be done once the genome sequences of these phytopathogens are available was also made clear, with the speakers discussing the use of comparative and functional genomics to understand their evolution, biology, epidemiology, plantmicrobe interactions and pathogenicity.
A particularly prevalent topic was the evolution of phytopathogenic bacteria with the uptake of various pathogenicity determinants through horizontal acquisition. The first session was opened with a keynote talk by Boris Vinatzer who gave great insights into the evolution, epidemiology and plantmicrobe interactions as divulged by the genome sequencing and comparison of various Pseudomonas syringae strains from a range of hosts. After lunch, Mark Achtman gave an excellent talk about a very different topic, looking at the genomes of genetically monomorphic animal pathogens including Staphylococcus aureus, Salmonella enterica Typhi and Yersinia pestis.
Thirty-two posters were also presented on day 1 in the form of three minute presentations, which further emphasized the ingress of the genomics age in the field of phytobacteriology.
The field of Genomics is here to stay and will greatly enhance our understanding of how phytopathogenic bacteria evolve, interact with host plants, survive in the environment and cause disease.
Day 2: Taxonomy and Diagnostics Tuesday started with a session on Taxonomy. Once again the use of whole genome sequences was raised by the keynote speaker Kostas Konstantinidis, who discussed taxonomy through the use of genome sequences. This was followed by excellent talks about the use of microarrays and MLSTs for bacterial identification and classification as the phytobacterial community moves away from the use of single gene phylogenies to categorise bacterial species. The three minute poster presentations focused on the identification and functional characterization of pathogenicity determinants in a broad range of plant pathogenic bacteria. After lunch, the Diagnostics section began with a keynote talk by Jan Leach on the diagnostics developed for Xanthomonas oryzae based on the genome sequences of various strains causing different diseases on rice. This was followed by a number of talks on the use of various molecular methods to detect and identify various pathogens including Xanthomonas arboricola, Xanthomonas fragariae, Dickeya solani and Ralstonia solanacearum. The last poster presentation session of the day covered various aspects including identification, detection, host resistance and pathogenicity factors.
Day 3: Field trip Delegates were given a day off on Wednesday to digest and discuss the information that had been presented over the previous two days during an awesome trip to the volcano, Piton de la Fournaise” on the Island of Reunion. For most of the delegates, being on top and walking in the crater of a volcano was a first and an unforgettable experience.
After this, we were treated to a traditional meal and drinks at a geranium oil distillery, followed by a scenic trip around the Island, to “Jardin des Mascareignes” (Botanical Gardens of Marscareignes”. It was very interesting to learn about the current projects regarding conservation of the floral biodiversity of Reunion, and to walk around the beautiful, tropical gardens. Day 4: Molecular Plant Pathogen Interactions & Plant Resistance The first session on Thursday was dedicated to molecular plant-microbe interactions and plant resistance. Mari- Ann Newman started proceedings discussing recent developments into MAMP/PAMP research. This included peptidoglycan, LPS, EF-Tu and flg22 research. She nicely showed that peptidoglycan molecules trigger dosedependent basal immunity and that alternative forms of peptidoglycan (from different bacterial pathogens) have differential activity. There was also discussion relating to additive and synergistic effects of different MAMPs on triggering basal resistance. These findings perfectly complemented the talks of David Guttman and Boris Vinatzer (on Monday). David Guttman presented a very elegant screen to identify PAMPs within genomes. He first discussed the PAMP paradox i. e. that PAMP proteins are under negative selection to maintain function but under positive selection to avoid host immunity. Thus, analysis of the core genome should be able to identify candidate PAMPs by identifying proteins exhibiting a positive selection signature based on the Ka/Ks ratio. About 50 candidate PAMPs were identified in this way and these were validated by production of peptides and quantification of callose deposition after infiltration to plants. Further validation was done by testing the effects of PAMPS on bacterial growth. Frederique van Gijsegem provided a very good talk on global regulation of virulence genes during the Dickeya-Arabidopsis infection. By using a combination of gacAS, pecS and mfbR mutants, she showed an intricate web of regulation turning genes on and off at different stages of infection. Jonathan Jacobs gave an interesting talk detailing use of a microarray to identify Ralstonia solanacearum gene expression in tomato stems and subsequent characterisation of a sucrose utilisation gene cluster important for initial growth in the stem. Vittorio Venturi showed us the complexities underlying community interactions, describing how Pseudomonas, Xanthomonas and Burkholderia can all interact on a single rice plant. Moreover, these bacteria can in some cases communicate via quorum sensing systems. After another session of poster flash-talks, it was time for the conference dinner, which was a firstclass meal with local Reunion entertainment. A great time was had by all, until early the following morning.
Day 5: Control, Epidemiology & Ecology Friday’s first keynote talk was presented by Tim Gottwald on the epidemiology of Huanlongbing in citrus.
In this extremely interesting talk, Tim explained how the spread and epidemiology and dispersal of this disease has been unraveled using various modeling techniques. The two speakers following Tim Gottwald continued in the line of epidemiology, explaining the use of molecular techniques and other modeling approaches in understanding epidemiology of Xanthomonas fragariae and X. citri pv. citri in strawberry and citrus, respectively. After coffee we heard about interesting findings regarding the At plasmid in Agrobacterium tumefaciens, as well as important bacterial disease threats on various agricultural crops. Joyce Loper, keynote speaker after lunch, held our attention by expounding how the use of genome mimicry has been used to study biocontrol strains of Pseudomonas. She explained the interesting and unexpected findings from these studies. The remainder of the talks in this session focused primarily on new and emerging bacterial diseases of crops, with particular focus on potato and banana.
The last session of the day was dedicated to detection, diagnosis and control of bacterial diseases on potatoes, with special reference to the Pectobacterium / Dickeya disease complex and the new devastating Zebra Chip disease.
This superb conference with outstanding talks which sparked lively discussions, as well as excellent food and organization, was closed with election of the scientific committee for the 13th ICPPB to be held in 2014 in China. We would like to thank the Organizing and Scientific Committees of the 12th ICPPB for this exceptional conference, and the BSPP for granting us the travel grants to help fund our attendance thereof.
Pieter de Meyer1, Rob Jackson2, Ian Toth3 and Jacquie van der Waals1 1University of Pretoria, South Africa 2University of Reading, UK 3SCRI, UK Following on from the successful, Dundee Workshop and Edinburgh Conference in 2006, the 2nd workshop and the 12th conference were held in Saint Denis, Reunion Island. Around 200 bacteriologists from more than 40 countries attended. You may ask why Reunion? It is undoubtedly distant from almost all the major centres of population and scientific effort and this was the first international gathering of its kind to be held on the island. Yet Reunion, which is administratively an integral part of France, is in itself a major centre in the study of tropical pathogens, with large groups studying the diversity, epidemiology and control of significant bacterial pathogens including, Ralstonia solanacearum and Xanthomonas citri. The fact that these meetings took place on a tropical island, with sun-kissed beaches lying in the middle of the Indian Ocean, is entirely incidental to the plot! The workshop, which preceded the conference was organised by University of Pretoria, South Africa, and brought together approximately 40 specialists from across the globe. The genus Erwinia, as was, has undergone major revision in recent years spawning further genera, with the plant pathogens now spread across Brenneria, Dickeya, Enterobacter, Erwinia, Pantoea and Pectobacterium.
Despite this diversity, a fair proportion of the workshop was taken up with one major topic, namely the emergence of new pathogen of potato in Europe, specifically ‘Dickeya solani‘. The effects of this pathogen were first noted in 2005-2006, though speculation suggests it emerged around 2000. It was recognized as a new species in 2009, though it is yet to be formally named. As two-way international trade in potatoes interlinks Northern Europe with the potato producing areas in the Mediterranean Basin; selling seed potatoes to North Africa and the Middle East whilst importing ware potatoes when our own supply is exhausted late Winter/early Spring, the workshop provided an excellent opportunity to discuss this problem from both ends of the supply chain and gain insights into how this pathogen manifests itself in very different climatic conditions. It was evident from the workshop that research into this pathogen is very much in its infancy, so watch this space in terms of future conference reports and publications in the years to come.
Moving onto the conference proper, it was logically divided into four sessions covering; Genomics & Evolution, Taxonomy & Diagnostics, Molecular Plant Pathogen Interactions & Plant Resistance and Control, Epidemiology & Ecology. The conference also successfully established some crossover with parallel research efforts from the clinical environment, most notably with a keynote presentation from Mark Achtman, University College, Cork.
Mark highlighted some of the drivers for bacterial speciation, covering the role played by horizontal gene transfer (HGT) in the emergence of new species, as uncovered in a number of studies from the mid-90s. He then went onto discuss the new thinking emerging as a result of the explosion of data from next generation sequencing projects, specifically the role of homologous recombination plays in reducing diversity to bring cohesion and clustering individuals into discreet species, citing Yersinia pestis as a prime example of these monomorphic species.
In the clinical arena, many of the most virulent bacterial pathogens are genetically monomorphic, and understanding their evolutionary and phylogeography will facilitate their control, it is likely that the same will also be true for many bacterial pathogens.
As to the social programme, a trip to an active volcano, lunch at a small family run geranium oil producer and a stroll around a botanical garden amounted to an unforgettable experience. The conference dinner, held at the seat of the local government, was also memorable as was the dancing on offer from the various BSPP members in attendance (naming no names!), who’s willingness to sample all the local produce in all its various liquid forms was also much evidence. Though, undoubtedly watching the sun go down over the Indian Ocean was in truth the once in a life time experience.
Malgorzata Kowalewska and Gerry Saddler, SASA, Edinburgh
