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29th Fungal Genetics Conference, Asilomar, USA 14th – 19th March 2017
The Fungal Genetics Conference (FGC) meets every two years at the historic Asilomar conference grounds on the Pacific Coast near Monterey, about 120 miles south of San Francisco. Although nominally a “genetics” conference – it is formally organised by the Genetics Society of America – the FGC is really a very broad mycological meeting with researchers working in all aspects of fungal biology. This is probably a credit both to the influence that genetics has had on our deep understanding of the biology of the fungi (and oomycetes) and, reciprocally, the seminal contributions of fungi to the field of classical and molecular genetics as well as genomics over the past decades.
It is hard to overstate the breadth of the science presented and discussed at the FGC meetings in Asilomar. A glimpse of this may be gained by scrolling through the titles of the specialist concurrent sessions. This year there were about 7 daily sessions, which range from purely mycological themes such as mating and clonality in fungi, fungal biodiversity, secondary metabolism, to broader aspects of interactions with other organisms (plants, humans, other microbes). The sessions also include topics that impact fields outside those strictly mycological, for example biotechnology, metabolic engineering and synthetic biology.
The highlights of the meetings are usually represented by plenary talks held in the large wooden beamed historic Merrill Hall that just about fits most of the attendees (there is a video relay overspill to a separate venue). One of the particularly valuable features that distinguishes the FGC is the care the organisers take to ensure both a broad diversity of speakers in terms of both topics, identity and origin (place of work). This is highly commendable, as is the strict limit which prevents the same “big shots” appearing on the main podium year after year: it ensures that new topics, new faces and new ideas are given the maximum exposure.
Unlike many other venues for large international conferences, Asilomar is an easy place to get around and to find people. Both random encounters at the three meals and planned get-togethers are effortless and are another special feature of this meeting. However, the three evening poster sessions are the main opportunity to discuss hard-core science in all its nitty-gritty detail. The initial reticence to approach strangers is helped by the availability of drinks and nibbles which certainly does wonders to break down barriers to conversation.
The science presented at the meeting is near-universally stunning. This is particularly so at the plenary sessions. From my (biased) point of view the highlights were represented by the two talks on aspects of cross-kingdom RNA signalling in plant-fungal interactions. The first one, by Wembo Ma on the role of Phytophthora infestans effectors in interfering with the immune system of the plant; she described how the oomycete pathogen produces proteins that are delivered to the host cells and affect their small RNA metabolism and regulatory activity, ultimately leading to enhanced susceptibility. The second plenary talk on this theme was delivered by Hailing Jin who described the two way exchanges of small RNAs between plant hosts and fungal pathogens (such as Botrytis, Verticillium and Fusarium). These are exciting stories indeed: the big challenge ahead now appears to be trying to make sense of how these molecules are actually exchanged. The pathways for effector protein delivery are still not really understood and not much progress has been made on this issue, and the movement of RNA between eukaryotic cells of different kingdoms is wholly unknown. The third plenary talk I wish to highlight was by Bettina Tudzinski who talked about her work, spanning decades, to understand the processes involved in secondary metabolite production in Gibberella (Fusarium) fujikuroi. I was particularly intrigued by the original and ultimately successful way of determining the purpose of some of the many poorly understood gene clusters hypothesised to encode proteins for the synthesis of complex metabolites. The question was: which metabolites? Intriguingly, Bettina and her co-workers managed to determine this by artificially activating the genes in vitro culture, so that the metabolites accumulated, could be analysed and be identified. A very elegant approach that probably belies the difficulty of the challenge. Amazingly it worked!
Fungal “genetics” and biology is blessed by having three regular high level international meetings which alternate such that there is at least one every year (the others are the European Fungal Genetics Conference and the Cellular & Molecular Fungal Biology Gordon Research Conference). The Asilomar FGC meetings take some beating, both with regards to science and venue. The 29th meeting was no exception. I thoroughly recommend attending the next ones for anyone interested in fungal biology in general, or fungal (and oomycete!)-plant interactions, in particular.
Pietro Spanu Imperial College London
Post scriptum. One of the very special aspects of Asilomar as a place to hold a conference is its location (pictured above): just behind a set of nature protected dunes on the spectacular Pacific Coast. Access to the beach is literally a five minute walk from the lecture and dining rooms. Perfect for breath of fresh air, a moment to relax or think, or simply go for a walk. Some of the most adventurous actually go for a swim…
The conference gathered around 1000 scientists and graduate students from all over the world. Over four days, all the delegates assembled every morning for the plenary sessions which covered broad aspects of fungal biology and emphasised the importance of fungal research in the wider scientific community. I particularly enjoyed a presentation on the role of Neurospora crassa research in understanding circadian clock. I also found fascinating a presentation on optogenetics, which consists in the utilisation of visible light to control gene expression. In this presentation the audience assisted to a real fusion between science and art as cultures of Neurospora crassa reproduced via expression of fluorescent protein-encoding genes, images that had been projected on them. The afternoon consisted of numerous concurrent sessions covering wide ranging topics. Evenings were dedicated to poster sessions during which hundreds of posters were displayed in a unique array of topics, colours and shapes. The extremely popular poster sessions were also a unique opportunity to learn in detail the latest discoveries in diverse domains. The poster sessions were a scientific event as much as a social event and allowed me to meet people with common research interests.
My research interest being on the plantpathogen interaction and primarily on secondary metabolism in fungi, I enjoyed the opportunity to assist at two sessions on secondary metabolism as well as on small secreted proteins and effectors. I was particularly excited by a presentation on the evolution of the PerA gene, a non-ribosomal peptide synthase responsible for the biosynthesis of the secondary metabolite peramine, produced by several grass endophytic species including Epichloe species. In this presentation, the evolution history of the PerA gene in numerous Epichloe species was revealed and linked with the presence of transposons resulting in the disruption of the C-terminal reductase domain involved in the release of the secondary metabolite product from the enzyme. The resulting gene which was originally thought to be non-functional produced a new cyclic compound released by intra-molecular cyclisation instead of reductase domainmediated inter-molecular cyclisation. I found this presentation extremely interesting as it exemplified how the evolution of a species secondary metabolome can be driven by events such as the insertion of a transposable element in a gene coding sequence. During the poster sessions I was particularly fascinated by a poster presenting the discovery a new secondary metabolite in a strain of Aspergillus nidulans grown aboard the international space station. This poster emphasised the complexity of working with fungal secondary metabolism as inducing the expression of gene clusters and subsequent production of secondary metabolites may require very specific conditions such as microgravity.
Overall, the conference was a very positive experience both scientifically and socially. In addition, walking the conference ground and its surroundings was a real pleasure as the Asilomar ground is also hosts to a vast array of wildlife ranging from deer and vultures to native plant species.
Francois Dussart SRCU
I wonder if there is a more attractive place to gather scientists from all around the world working on fungal genetics than at a magnificent site by the Pacific Ocean. Conference participants could enjoy their stay at cosy cottages and the conference sessions in historic buildings. The first surprise was to look outside the window and see deer!
The conference stimulated my interest from the first moment. During the first plenary session Wenbo Ma (University of California, Riverside) talked about Phytophthora encoding RNA silencing suppressors. These effectors play an important virulence role during infection, by suppressing small RNA silencing in the host plants. This is crucial, as RNA silencing mechanisms in plants suppress important pathogenesis -related genes. By increasing our understanding of RNA silencing, and therefore manipulating these host mechanisms, perhaps we are one step closer to being able to control important fungal pathogens and the spread of the disease.
Bart Thomma (Laboratory of Phytopathology, Wageningen University) presented work that took place in his lab at the concurrent session “Plant-Fungus Interactions”. He talked about the genome plasticity of V. dahliae and its role in the pathogen virulence evolution. He also presented work to identify crucial virulence factors of V. dahlia and the relationships between particular effectors and pathotypes.
Many other presentations stimulated my interest; particularly the one on CRISPR/Cas9 as a based toolbox for efficient genome editing of filamentous fungi by Uffe Mortensen (Biotechnology and Biomedicine, Technical University of Denmark). This technique is fundamental and can improve engineering of fungal species for different applications. Gene knockouts can be performed to study plant- pathogen interactions in depth that can inform plant breeding for future crop protection.
The poster sessions are one of the most memorable experiences of this conference. Each session was very well organised, with a great variation in topics that covered most of the aspects of fungal genetics. This was accompanied by Californian beers or wine and canapes satisfying everyone’s preferences. The poster I presented on “Characterization of necrosis-inducing NLP proteins in Leptosphaeria maculans and L. biglobosa“, stimulated fruitful discussions that broadened my knowledge about NLPs. Moreover, it helped me to incubate new ideas for future experiments to address further scientific questions.
The scientific discussions never stopped and were even taking place while walking on the beach and enjoying the sunset. Also memorable was the conference dinner and the subsequent party that featured a great local band which encouraged dancing between participants. Strange but interesting was a badge exchange between participants that was taking place during the party. I overall enjoyed the conference and I hope to participate again in future.
Dr Georgia Mitrousia University of Hertfordshire
Having heard colleagues excitedly discussing “Asilomar” in previous years, I was happy to hear that the 2017 Fungal Genetics Conference would include a session on “Evolution and Mechanisms of Antifungal Drug Resistance”, and even happier to be invited to speak in that session. Many readers will be all too familiar with the threat posed by fungicide resistance to crop protection, but resistance to clinical antifungals is also a growing problem, especially in immuno compromised patients. The resistance session at Asilomar, together with an associated plenary lecture, brought together resistance researchers from plant pathology and clinical mycology to discuss common themes across pathosystems.
We saw evidence of parallel evolution in shared resistance mechanisms, whether through target-site point mutations, or through enhanced efflux and other regulatory changes which are now becoming more tractable due to RNA sequencing. More fundamentally, we discussed the common evolutionary drivers leading to resistance across agriculture and medicine: the sources of adaptive potential in fungal populations, whether from pre-existing variation, new point mutations or more drastic chromosomal rearrangements, or even epigenetic processes; the evolutionary plasticity of genes and promoters; the strength of selection for resistance; but also the functional constraints that make some adaptive pathways more accessible than others.
The scale of fungal adaptive potential and genetic diversity was apparent across other sessions too, from genomic analyses revealing a growing list of gene transfer events between species, to the range of fungal secondary metabolites (toxic, useful or sometimes both!) for which biosynthetic pathways are being characterised. It was especially interesting (and worrying for our own lab strains!) to see the levels of chromosome copy number variation observed within a few generations of experimental evolution. A preconference workshop on Dothideomycete Comparative Genomics also provided useful updates on the population genetics and genomics of Zymoseptoria tritici and its relatives, mostly relating to plant-pathogen interactions. Also apparent were some interesting parallels between work on the virulence of fungi against their hosts, and the resistance of fungi against pathogens: both in terms of the genomic origins of toxin biosynthetic clusters and resistance-related genotypes, and in terms of the evolutionary trade-offs between overcoming the host or fungicide and any associated fitness penalties, and in the experimental approaches used to investigate these phenomena. As emerging genetic approaches lead to novel control methods for fungal pathogens, it will be essential to apply the lessons from the breakdown of existing control methods if we are to stay one step ahead in the ongoing arms race.
Dr Nichola J. Hawkins Rothamsted Research
2nd International Workshop on Barley Leaf Diseases, Rabat, Morocco 5th – 7th April
In early April I attended the 2nd International Workshop on Barley leaf diseases, which was held at ICARDA (International Centre for Agricultural Research in the Dry Areas) in Rabat. Around 60 people attended the conference, with delegates from Australia, India, North America, Ethiopia, Morocco and Europe. I am a PhD student based at the James Hutton Institute in Dundee, Scotland, and my research is on resistance to scald in barley. I was given the opportunity to present a poster and a 5 minute “Flash N Dash” talk.
I had not been to Morocco before, and was surprised to see how green it was. I was told this was because of the plentiful rainfall over the winter which has meant good prospective barley yields, but also more problems with pathogens! The conference began with a visit to ICARDA station Marchouch, a 2 hour bus ride away from Rabat. The station had ongoing field trials very similar to what we have here in Scotland, but due to the difference in climate in early April the barley is already at the grain ripening stage. Yield is highly reliant on the quite unreliable winter rainfall, as there is no irrigation. A highlight of the day was seeing over 2000 landraces growing for seed bulking which had been rescued from the ICARDA seed bank in Aleppo, Syria (which apparently amazingly is still running). We were also shown a farmer’s field and met the farmer. Unlike in the UK, barley breeding and seeds are produced by ICARDA in Morocco, and so breeding is done on a public basis, not by private companies.
I was interested to see that Scald was up there on the list of problematic barley diseases with Net blotch, Stripe rust, Leaf stripe and Spot Blotch. I always start my talks by saying that leaf scald is a problem in cool wet parts of the world, which I assumed did not include Morocco. However, as it turns out, as barley is grown over winter in Morocco, it provides an ideal incubation for many pathogens of barley, including scald. I spoke to Dr Zerihun Jalata, who works on barley resistance to leaf diseases in Ethiopia and he said the same problem also exists over there, where barley grown in the wet season in the highlands is very susceptible to scald.
The second day of the meeting was based around talks about host resistance and molecular pathogen interactions. The longevity, expense and difficulty of cloning barley R genes was highlighted, though new technologies such as genome sequencing, exome capture, high throughput genotyping and association mapping have definitely helped research in this area. A highlight of the day was hearing about QTL mapping of the virulence of the net blotch pathogen Pyrenophora teres. This was combined with genome sequencing of the pathogen and was used to find effectors and genes responsible for increased pathogen virulence. This was interesting because it was the first time I had heard of QTL mapping being used to map pathogen virulence, as normally it is used in mapping host resistance. In the evening we had an amazing dinner close to the beach and lighthouse in downtown Rabat. We ate traditional Moroccan food; various tagines, seafood, some pastries and couscous. Much of the food is surprisingly sweet, and the meal is always finished off with sweet Moroccan mint tea, which by the end of my stay I couldn’t get enough of!
On the third day of the meeting we heard talks about integrated management of barley disease and pathogen population evolution. There were also the Flash N dash short talks where I gave a summary of my poster. Overall I found the conference immensely enjoyable, and very helpful. It helped me to think about the wider context of my research, bring the realisation that Scald is not just a UK problem. It also stressed to me the importance of developing molecular markers for R genes, so that breeders can easily incorporate resistance by marker assisted selection. There seems to be a wide collection of ICARDA germplasm available, which combined with high throughput sequencing and genotyping could enable us to find more resistance against barley leaf diseases. It was also a great opportunity to visit Morocco, and see its vibrant culture and taste a real tagine!
Max Coulter James Hutton Institute
20th Triennial Conference of the European Association for Potato Research (EAPR): Potato Facing Global Challenges, Versailles, France 9th – 14th July 2017
Potatoes are the third most important food crop worldwide. The EAPR aims to foster their sustainable production by promoting the exchange of information on potato breeding, production, protection and use. In the EAPR’s 60th anniversary year, its 20th Triennial Conference was held in Versailles attended by about 430 delegates from over 50 countries. The initial challenge was to reach the Congress Centre; travel across Paris on the arrival day was complicated by a railway line closure, but it was worth the three-hour struggle! The venue, with a fine view of the Palace, was splendid and we were welcomed by the EAPR President, Michel Martin, ARVALIS.
Among the keynote lectures, I found those focussing on potato production in developing countries particularly interesting. Hans Dreyer described the FAO’s role in sustainable potato production in Africa, partnering with family farms, Elmar Schulte-Gelderman discussed CIP (International Potato Center) research in Africa and Teresa Mosquera (National University of Colombia) gave an inspiring presentation on her work using a participatory breeding approach to develop cultivars rapidly adopted by farmers which provide enhanced nutritional benefits. As a tuber crop, potatoes provide more food per unit area than grains and are more water efficient. They are higher in protein than other root and tuber crops, are an important source of vitamin C and help to supply deficient micronutrients (iron, zinc), combating malnutrition. Access to good quality seed potatoes is a major limiting factor: in many developing countries formal seed production systems are weak or non-existent, but technical support can improve informal systems avoiding use of unhealthy seed and inadvertent spread of pests and diseases. Delegates were told, however, that there is a need for greater co-ordination of projects between CIP, FAO and NGOs.
In a session on emerging bacterial diseases, we heard that the complex taxonomy of the genera Pectobacterium and Dickeya, which cause blackleg and soft rot, is being gradually unravelled. Khaoula Chawki (INRA, France) reported that at least five Pectobacterium species and sub-species are responsible for blackleg in France (whereas in Scotland blackleg is almost all caused by P. atrosepticum, as noted by Ian Toth, James Hutton Institute in a later paper on developing an IPM toolbox for blackleg). P. carotovorum ssp. brasiliense is increasing in importance worldwide; studies in France and Turkey indicate variability within this organism. Lucy Moleki (University of Pretoria, South Africa) showed that its success may be due to its ability to inhibit other bacteria within potato tubers. Another threat is ‘Candidatus Liberibacter solanacearum‘, a psyllid-transmitted bacterium which causes zebra chip in the Americas and New Zealand. Neither the bacterial haplotypes nor the psyllid vector associated with zebra chip occur in Europe, but other haplotypes have been found in plants of the Apiaceae (including carrots and parsley). Studies reported by Anne- Claire Le Roux (INRA) indicate a low risk of transmission to potatoes by current European psyllid vectors, but if the zebra chip vector (Bactericera cockerelli) were introduced to Europe that could change.
Potato late blight is the subject of a new European project IPMBlight 2. 0, which started in 2016 and aims to use pathogen population information to improve control ultimately by including it in DSS. Didier Andrivon (INRA, France) presented first findings from this project. He pointed out that, although it is not possible to predict where and when the next significant new Phytophthora infestans genotype will emerge, epidemiological vigilance flags up new dangers at an early stage e.g. monitoring has already detected the appearance of the new genotype 37_A2 associated with reduced sensitivity to the fungicide fluazinam. This project, which developed from the European late blight network, EuroBlight, demonstrates the value of such international networks. This was also the theme of my poster on AsiaBlight (a late blight network for Asia), which I am helping to coordinate, working with Greg Forbes, CIP (I retired from the Agri-Food & Biosciences Institute in 2015, but hold an honorary position in the Queen’s University, Belfast). I reported progress in our initial project, developing a coarse-scale map of P. infestans in Asia, using some of the same monitoring techniques to genotype the pathogen population.
On the middle day of the conference, delegates had a choice of excursions. My group visited the ARVALIS experimental centre about 80 km south of Versailles. I was particularly interested to see their late blight fungicide trial: infection in fluazinam-treated plots was very severe compared with the other treatments. The trial had been inoculated with 2017 P. infestans isolates, not yet genotyped: I wondered if this was an example of infection by 37_A2. After an excellent lunch at the ARVALIS Institute (impressively this was produced by their regular canteen staff using local produce!), we visited Parmentine, a modern, highly-automated potato packing facility, owned by growers. Finally in Chartres I was delighted to see the cathedral, which I’d visited more than 20 years ago when attending the 12th EAPR Triennial in Paris, has been splendidly cleaned and restored and looks wonderful.
The conference also marked the launch of the new and greatly improved EAPR website, see www. eapr. net. I would encourage any BSPP member with an interest in potatoes to consider joining: although a European organisation, members are drawn from across the world united by their dedication to that fascinating crop, the potato. Benefits include access to the EAPR’s journal Potato Research and the American Journal of Potato Research (there’s a reciprocal arrangement with the Potato Association of America) and meetings of the five Sections, including Pathology & Pests, which occur between Triennial Conferences. The EAPR helps to support young researchers and provided grants to 24 student attendees from 18 countries to assist their participation in this Triennial. I am very grateful to the BSPP for their financial support towards my attendance, which helped me inform my fellow delegates about AsiaBlight.
Louise Cooke Queen’s University, Belfast
13th International wheat genetics symposium, Tulln, Austria 24th – 28th April 2017
The 13th International Wheat Genetics Symposium took place in Tulln; a small town on the Danube river, approximately 30 km northwest of the Austrian capital, Vienna. The symposium was certainly an international affair, with approximately 500 participants attending from 64 countries! We were welcomed to the symposium with talks from representatives of both local and international organising committees and the Mayor of Tulln, with musical entertainment provided by the local middle school.
The opening lecture, by Professor Helmut Heberl, highlighted the value of wheat research by discussing his modelling work in feeding the world whilst avoiding deforestation. His insightful, if somewhat controversial, presentation discussed his calculations for achieving food security in 2050 under different assumptions. He highlighted the importance of reducing meat consumption to food security, as lower meat diets use crop resources more efficiently. However, he claimed that using only organic farming methods, even in their current form, could be sufficient in feeding the world; a statement that raised some discussion during questions.
The symposium programme provided a diverse coverage of wheat genetics research. There were talks discussing genetics underlying plant development characteristics, such as inflorescence architecture and pre-harvest sprouting. Utilising wheat relatives to increase genetic diversity and introgress useful traits to wheat was a common topic. There were also talks highlighting the genetic and genomic resources available to researchers, such as an update on the latest genome sequence assembly and how it was constructed. Plant pathology was a recurrent theme at the symposium, with a number of talks on mostly fungal diseases of wheat, such as rusts, Septoria tritici blotch and, the topic of my own research, Fusarium head blight.
My personal highlight of the symposium was the special session on the identification and characterisation of Fhb1; a QTL conferring the best-known resistance to Fusarium head blight in wheat. Four speakers discussed their research and, astonishingly, they have all identified different genes in the Fhb1 region which they believe to be Fhb1!These included a pore-forming toxinlike gene, a mutated histidine-rich calcium- binding protein and a mycotoxin detoxification gene. This prompted a lively panel Q&A session in which speakers agreed to share germplasm, in an effort to solve the Fhb1 mystery!
There was a strong student presence at the symposium, with two seminar sessions exclusively presented by PhD researchers. Many posters were also presented by students. More than 300 posters were displayed at the symposium. My own poster, on the topic of a Fusarium head blight susceptibility factor in wheat, prompted some fruitful conversations with both scientists and breeders.
Attending the 13th International Wheat Genetics Symposium was an invaluable experience. It enabled me to hear about some fascinating current wheat research and interact with researchers from outside the UK. The BSPP travel grant I received to attend was greatly appreciated.
Ben Hales John Innes Centre
12th European Foundation for Plant Pathology (EFPP) – 10th French Society for Plant Pathology (SFP) Conference, Dunkirk, France 29th May – 2nd June 2017
I attended the 12th EFPP-10th SFP conference entitled ‘Deepen knowledge in plant pathology for innovative agroecology’. The week-long conference was a great opportunity to interact with the international plant pathology community. The meeting was particularly special because it integrated three plant pathology societies including EFPP, SFP and the American Phytopathological Society (APS). With many sessions, the conference covered a wide variety of plant pathology issues, which were brilliantly summarised in the final session by Monica Höfte, from Ghent University into three major areas: threats, opportunities and challenges.
Emergent plant diseases and high throughput genomics were covered in the keynote session, by Sophien Kamoun, The Sainsbury’s Laboratory, UK. Sophien described the major outbreak of the wheat infecting strains of Magnaporthe oryzae (causing wheat blast). This disease has been a significant problem, since the 1980s, in South America. However, in 2016, a major outbreak of wheat blast occurred in Asia for the first time in Bangladesh. Sophien and his team rapidly assembled an open source website, where M. oryzae genome sequences could be deposited and accessed for the global plant pathology community to perform analysis to ‘look into the soul’ of plant pathogen epidemics. Combined with field pathogenomics, this rapid response quickly allowed detailed genetic information about the isolates recovered from Bangladesh. This confirmed their South American origin and should soon allow for wheat cultivars with known host resistance to be grown in the affected area in Asia. In addition to the rapid plant pathogen problem solving that this talk highlighted, the true power of collaborative and open source research was shown.
A particularly interesting talk from Maarten Ameye, from Ghent University, Belgium, covered when plants ‘scream’ through production of green leaf volatiles. The effects of wheat (Triticum aestivum) leaf volatiles in plant priming – when plants are alerted early to promote faster and/or stronger response to future pathogen attack – were studied in this work. Previous research has shown that the volatile Z-3-hexenyl acetate (Z-3-HAC) can enhance defence against the wheat ear pathogen Fusarium graminearum. Further to this, recent results using untargeted metabolics in plants primed/not primed with volatiles have found that Z-3-HAC has both a large effect on the metabolism of primary nitrogen and induced glycosylation of metabolites. This also resulted in large upregulation of salicylic acid production and a down-regulation of the benzoxazinoid DIMBOA, showing that plants can communicate through the air to induce responses in plant defence hormones. This research could in future lead to biocontrol and/or integrated disease management in wheat crops for plant diseases.
Finally, a new answer to the continuing challenge of fungicide resistance in the wheat pathogen Zymoseptoria tritici – Septoria tritici blotch, was presented by Lisa Nistrup Jorgensen, Aarhus University, Denmark. Resistance to all the major classes of fungicides has been found in Septoria. In Lisa’s talk a novel mode of action of the picolinamide fungicides was presented. Formulated in a new fungicide called InatreqTM Active, produced by Dow AgroSciences (active ingredient: fenpicoxamid). This has been found to be active against Septoria, with no cross resistance to any of the major classes currently used to con- trol this disease.
Overall this conference covered the all the current major themes in plant pathology over five days: global change (including climate, on-farm plant protection and trade); new tools for studying plant pathology; phytopathogen phytobiome interactions (supported by APS); influences of plant pathology on other scientific domains; in addition to recommendations of disease control which included novel, historical or repurposed methods. It was a great week of science, enhanced by the French food and wine!
Joseph Moughan, Rothamsted Research and the University of Exeter
HPIS 2017 – 3rd Hemipteran-Plant Interaction Symposium, Madrid, Spain, 4th – 8th June 2017
Hemiptera is an insect order that includes from 50,000 to 80,000 species, comprising cicadas, aphids, leafhoppers and planthoppers, among other. The vast majority of the hemipterans feed on plants and establish different types of ecological relationships with their hosts. Hemipterans can produce severe harm to their plant hosts either because they suck the plant sap or because they can transmit viruses or pathogenic bacteria. Therefore, the characterisation of the ecology and epidemiology and the management strategies of many important plant diseases require knowledge about the interactions between the pathogens, the plant and the insect vector. The HPIS 2017 meeting addresses this particular area of research, in which entomology and phytopathology meet.
One of the aspects that called my attention was the wide variety of questions that are being addressed using oomic approaches. For example, comparative genomics has been used to infer the basis of generalism in aphids, to study the expression of predicted secreted proteins of salivary glands of aphids and their role as disease or vector effectors or to characterise single insect transcriptomes of whiteflies from different populations. Also, the feeding insect behavior of two pentatomids was studied by proteomic analysis of their salivary glands and the transcriptome changes of Bemisia tabaci in response to feeding in plants infected with a Crinivirus. Oomics also revealed that female and male adults of Diaphorina citri responded similarly to exposure to ‘Ca. Liberibacter asiaticus‘ and in a different work the protein effectors that allow the invasion of the psyllid Diaphorina citri gut and salivary glands by this pathogen, were amply described. The effect of RNA viruses in the efficiency of RNAi in aphids was addressed by sequencing the small RNAs and transcriptome of three species of aphids. Later, miRNAs that targeted specific genes were introduced and the effect of silencing measured in relationship with the virus infections. The use of miRNAs to silence gene expression in insect vector appears as the preferred tool for several studies.
A very remarkable discovery for me was the EPG (electrical penetration graph monitoring) technique which allows the observation and quantification of the otherwise invisible feeding behavior of piercing-sucking arthropods. This technique reveals the steps of the stylet pathway during insect feeding and transmission of virus or bacteria to host plants. Using this technique, it was shown that the colonisation of the insect vector by Xylella fastidiosa increases the probability of successful inoculation behavior, the type of specific punctures that aphids have produce to transmit Beet yellows virus, the detailed process of stylet penetration and sieve element occlusion that leads to compatible or incompatible aphid plant interactions and the role of plant volatiles in the preference of hosts plants by aphids. Very importantly, evidence was presented of the ability of Scaphoideus titanus to feed on the xylem, the insect vector of Flavescence doree phytoplasma to grapevines in Europe that is usually considered a mesophyll feeder. This makes S. titanus a candidate vector for transmission of xylem pathogens such as X. fastidiosa.
Other very interesting information was related to the characterisation of the bacteriome, the ecologic role of symbiotic bacteria, acquisition means by insect vectors and the fitness consequences of the presence of these bacteria for the insect survival and its ability to transmit pathogens. The evidence suggests the important role of these bacteria in the life of the insect but also appears as possible source of biological control and of modulation of pathogen transmission.
A group of presentations focused on the intimate details of insect-virus-plant interactions and in many cases addressed the problem of multitrophic relationships between the participants of these pathosystems. Remarkable results showed that in some pathosystems the insect vector fitness increases when infected with its associated pathogen, in cases such as: wheat – Barley yellow dwarf virus – Rhopalosiphum padi in a water dependent manner, in two brassicae plants – Turnip yellows virus — Myzus persicae in a plant species manner, in citrus – ‘Phytoplasma aurantifolia‘ — Diaphorina citri and in Arabidopsis thaliana – Aster yellows phytoplasma – Dalbulus maidis pathosystems. In this last case, it was also shown that phytoplasmas modulate the non-host resistance by introducing effector proteins to the host plants.
Additionally, the proteins and molecular processes involved in the specific identification of virus or bacteria and their insect vectors where described for a number of pathosystems. In particular, very interesting evidence was presented about the specific involvement of protein effectors such as MIFs (proteins of the cytokine family associated with the regulation of the immune response in animals) in aphids that seems to inhibit plant response, the Mp10 protein which suppresses the first layer of the plant defense response in aphid susceptible plants and the ability of aphid proteins to target plant proteins to favor the aphid virulence.
Finally, more traditional techniques also were used to report the presence of vectors in different part of the world, for example the identification of vectors of X. fastidiosa in Mallorca, Spain and Iberian Peninsula, psyllid vectors of ‘Liberibacter solanacearum‘ in the UK and Sweden, a revision of the aphid composition of Turkey, the composition richness and abundance of Cicadellidae in an area of Colombia, the distribution patterns of vector Philaenus spumairus of X. fastidiosa in Central Italy, among others. These evidence provides practical information needed for the management and mitigation of many diseases.
In conclusion, the meeting was fantastic because of the very specific subject it addresses, the remarkable quality of many presentations, the excellent organisation of the conference and beautiful venue at the CSIC in Madrid. I hope I will be able to put at the service of the problems that we have in Colombia the information about the last trends in the study of hemipteran vectors. The meeting was also an opportunity to meet again some colleagues and to make new contacts that will allow the progress of my line of research. Finally, I would also like to thank the BSPP for the financial support which allowed me to attend the meeting.
Liliana Franco-Lara Universidad Militar Nueva Granada, Colombia