Conference Reports International Union of Microbiological Societies (IUMS)
Congresses '96 International Union of Microbiological Societies (IUMS)
Congresses '96 The International Congress of Microbiology was jointly run by the Mycology Division and the Bacteriology and Applied Microbiology Division of IUMS, encompassing plenary, round-table invited papers and poster sessions. A poster entitled "The comparative use of genomic fingerprinting techniques for the characterisation of Ralstonia (Pseudomonas) solanacearum" (J J Smith, M Holderness, G Saddler) was presented. In addition, as the current BSPP representative on the ICSB, I was able to attend ICSB sessions running concurrently with the IUMS congress. ICSB meeting The ICSB meeting was split over three sessions and was dominated by discussions of the Draft BioCode: The Prospective international Rules for the Scientific Names of Organisms (Ed. D L Hawksworth - copies available from G Saddler, IMI). Other areas for discussion included the publication of theInternational Journal of Systematic Bacteriol ogy (IJSB) the use of bacterial patent strains as type material, the status of partially described taxa (Candidatus), the need for minimal standards and the use of dead specimens as type material. a) BioCode - The new Code attemps to harmonize the major bionomenclatural codes (bacteriological), botanical and zoological, with special provision for viruses and cultivated plants) and governs the formation and choice of scientific names but not the definition of the taxa themselves. Existing codes of nomenclature will continue to operate for names of the past, but after the implentation date (proposed for 1 January 2000), the new Code will operate for names published after this date. The production of this highly detailed discussion document invites comment from interested parties prior to 31 December 1996 and these should be addressed either directly to David Hawksworth, IMI or through the ICSB's representatives on the International Committee on Bionomenclature (ICB; Peter Sneath, Leicester University, UK & Brian Tindall, DSMZ, Germany) for amalgamation into the final document. During this meeting the new Code was discussed at some length and a large num,ber of points of clarification, and amendments will be forwarded to ICSB's representatives on the ICB. Clearly, established members of the ICSB are happy with the Bacteriological Code as it stands, and remain to be convinced of the worth of this initiative. Turning to specific issues, the new Code will not cover taxa below the rank of subspecies and therefore will not directly affect the working of the ISPP Sub-committee for Taxonomy of Plant Pathogenic Bacteria and their published guidelines for the naming of infraspecific taxa such as pathovars. b) IJSB - The journal is currently published quarterly on behalf of ICSB by the American Society for Microbiology (ASM) and has a circulation of approximately 2000. ICSB was recently informed by ASM that IJSB is operating at a loss and therefore package of measures to improve the financial status are being examined which include the introduction of page charges (not favoured by the ICSB), increasing the subscription rate or moving the journal to an alternative publisher. c) Patent strains - It is widely recognised that access to type material is vital for making valid comparisons or identifications of bacteria, and that this material should be available from "recognised culture collections". In this regard, a problem arises when type material is also the subject of a pending patent and therefore not freely available. The ICSB has therefore endorsed the view that the name should not be validated (published in IJSB) until the patent is awardfed and the material becomes available from a recognised culture collection. d) Candidatus - The ICSB endorsed the recent proposal to adopt a new procaryotic category, Candidatus, to cover taxa that can only be described in limited terms, for example, sequence information from a uncultivable procaryotic organism (Murray & Stackebrandt, 1995, Taxonomic note: Implemention of the provisional status Candidatus for incompletely described procaryotes, IJSB, 45, 186-187). At present the ICSB has stated that "the integrated use of phylogenetic and phenotypic characteristics, or polyphasic taxonomy, is necessary for the delineation of taxa at all levels from kingdom to genus" and thus does not encourage microbiologists to base a taxonomic description solely on phylogenetic placement inferred from comparison of nucleotide sequences. Currently, the worth of sequence information is almost universally accepted in phylogentic and systematic studies and this new proposal will grant the status Candidatus only to uncultivable procaryotic taxa for which relatedness has been determined and authenticated by in situ probing. This designation is not a "rank" but a "status" and as such is not recognised by the Bacteriological Code. It is possible that this proposal may have implications for the nomenclature of uncultivable plant pathogens such as phytoplasmas (mycoplasma-like organisms). e) Minimal standards - As stipulated in the Bacteriological Code "Before publication of the name and description of a new species, the examination and description should conform at least to the minimal standards (if available) required for the relevant bacterial taxon". Unfortunately few minimal standards have been produced for bacterial genera. Therefore the production of a "Taxonomic Note" was encouraged to give guidance where minimal standards did not exist. This publication would list general principles such as: descriptions should be based on as many strains as possible; descriptions should incorporate characteristics derived from a variety of techniques, which should include genotypic data; descriptions should encompass comparative studies with related taxa; illustrations should be included where appropriate; details should be given of ecological data and where the strains/material are deposited. The production of this "Taxonomic Note" was endorsed and should serve as the bench mark for future work, especially when dealing with genera for which no formal minimal standards exist. f) Dead bacterial specimens - Bacteriology has traditionally relied heavily on living cultures in culture collections and has shown little interest in dead preserved material. Technical advances in molecular biology have greatly increased the potential of dead preserved material. In this regard, nucleic acid sequences can be obtained from dried material by the use of PCR. Although the Bacteriological Code has made provision for preserved materials to be the types of uncultivable bacteria, this has seldom been used. The present suggestion was welcome as dried specimens are cheap to prepare and maintain and offer the only method for preserving uncultivable microorganisms. g) Other business - In addition, I was able to bring the ICSB up-to-date on some recent work by the ISPP sub-committee for Taxonomy of Plant Pathogenic Bacteria, namely our recent publication of a complete listing of all plant pathogenic bacteria names currently in use at 31 December 1995 (Young et al., 1996. Names of Plant Pathogenic Baveria 1864-1995. Review of Plant Pathology 75, 721-763). The ICSB also welcomed the sub-committee's intention to set-up WWW access to this material with a plan for annual updates. IUMS meeting Sessions of particular interest were related to systematics and ecology, bioremediation and waste water treatment, biological control and the release of genetically modified organisms. In all of these sessions it is apparent that the trend is towards the increasing use of molecular methods. It was evident that these methodologies are dominant throughout all branches microbiology and will continue to be so in the foreseeable future. Prof Erko Stackebrandt and his group at the German culture collection (DSMZ) have shown that within certain bacterial strains macroheterogenity in the 16S rDNA sequence is evident. In this regard, it is possible to detect 3 different types of sequence, the basis sequence, and/or with one or two introns (previously it was thought that only one sequence type was present in a strain). What is also interesting is that when the rRNA is sequenced directly only one type is found, with no insertions. At present there are no hypotheses as to why this should occur, but possibly some mechanism of post-transcript ional modification is operating, which may have implications for the use of rDNA and its role in inferring phylogeny of bacteria. Professor Karl-Heinz Schleifer (University of Munich) has perfected a range of in situ hybridisation techniques and applied these to studies of activated sludge treatments. From these studies, he has shown clearly that the use of selective media to study microbial diversity in such an environment can produce highly misleading results. Of three standard media compared against molecular methods, none were able to recover more than 20% of the prokaryotic diversity from this environment. In addition, each media selectively enriched for a different sub-set of the community, severely compromising the ability to assess diversity using traditional bacteriological methods. Dr Gary Sayler (University of Tennessee) chaired a lively session on current strategies for the release of genetically modified microorganisms (GMM's). Clearly there is a growing divergence on this issue between Europe and North America. In the US it is becoming easier to gain authorisation for such work (around 600 licences were granted in 1995) and genetically modified vegetables or those containing GMM's are currently sold in the shops. It would appear that the Europeans are working under much tighter constraints probably as a result of consumer confidence (or the lack of it in the field!). The point was made that the recent confusion caused within the UK over the BSE crisis could have a knock-on effect in areas such as the use of GMM's, particular in food crop production. Dr Stephen Farrand (University of Illinois) gave an interesting talk on the use of Agrobacterium tumefaciens strain K84 for the biocontrol of crown gall. Established thinking holds that K84 controls disease because it produced agarocin 84, it can only control agarocin 84 sensitive strains and strains of K84 which lose the ability to produce agarocin 84 also lose the ability to control. Recent findings would tend to challenge this view as K84 used under field conditions can control agarocin 84 resistant strains. The growing belief is that biocontrol is polygenic and may involve the production of other compounds such as agarocin 434 or sidero phores or simply because K84 is better at colonisation and survival on the host than other strains of the species. Gerry Saddler International Mycological Institute, Egham 9th International Conference on Plant Pathogenic
Bacteria The 9th International Conference on Plant Pathogenic Bacteria, hosted by the Centre of Advanced Study in Botany, University of Madras, was held at the Indian Bank Staff Training Centre, Madras, India. Around 95 delegates attended, represented 26 countries, including several eastern and western European, South American and African countries. The representation of India was quite remarkable for the number of delegates, presentations (48), and students present. There were 121 oral and 54 poster presentations organised into 11 sessions. Sessions I, II, IIIA, and IVA dealt with recent approaches in the diagnosis and characterisation of phytopathogenic bacteria; sessions III and IV dealt with physiology, biochemistry, and molecular biology; sessions V and VI dealt with epidemiology; sessions VA and VIA dealt with disease management & commercial exploitation; session VII dealt with plant resistance mechanisms & host specificity. On the first day, after the inaugural function in the presence of several stage government representatives, the conference began with a key note address by Dr Klement (Hungary) entitled "Interaction between the early induced resistance (EIR) and the hypersensitive response (HR)". This was followed by a second key note address from Dr Rudolph (Germany) about the role of polysaccharides in disease development. The first and second sessions presented several techniques for the characterisation and identification of Xanthomonads and Pseudo monads. An insight to the genetic diversity of Ralstonia solaneacerum, Erwinia amyhlovora and Pseudomonas syringae was presented in these sessions. Dr Lemattre (France) presented a particularly interesting paper about the use of ribotyping as a tool to characterise bacteria. The last paper of this day was mine entitled "Variation among populations of Pseudomonas syringae pvs. morsprunorum and syringae from sweet and wild cherry trees determined by carbon-source profiles and REP-PCR" (Luz & Shaw, the University of Reading, UK). The day concluded with an evening of classical Indian dancing performed by two amateurs who introduced us to the beauty of the Bharath Natyam dances. These dances, performed by women, usually tell events in Lord Krishna's life. The superb dinner that followed was full of the Tamil Nadu delicacies and considered by the foreigner delegates to be good but rather hot. The second day of the conference started with a brilliant key note address by Dr Lemattre entitled "Recent advances in diagnosis of bacterial diseases: new tools but for what purposes?". An exhaustive exposition of the methods currently available to identify and characterise bacteria was made summarising also the work that has been done at INRA, Versailles. Afterwards I attended the parallel session continuing the subject of the previous day, "Recent approaches in the diagnosis and characterisation of phytopathogenic bacteria". Different techniques were reviewed liked ELISA (Rajwsahawari, India), immunofluorescence colony staining (van der Wolf, Netherlands), fatty acid profiles (Parente, UK), and macro- restriction of genomic DNA resolved by pulse-field gel electrophoresis (Smith, UK). After lunch we were given two more lectures from Dr Sridhar (India) - "Molecular Characterisation of bacterial blight pathogen of rice and its utility for developing durably resistant varieties", and Dr Reddy (India) - "Phytosanitary measures against the introduction and spread of phytopathogenic bacteria". After these two lectures, I opted for the parallel sessions about disease management & commercial exploitation. An interesting paper in this session was about copper resistance in Xanthomonas campestris pv. citri (Canteros, Argentina). The day finished with another splended dinner but with not much time to have a proper look at the posters. The third day was dedicated to visits to three beautiful temples. The first, Sri Ekambaranathar in Kanchipuram, was started by the Pallava kings in the 7th century. In one of the enclosures there is a very old mango tree, claimed to be 3500 years old, with four main branches representing the four Vedas (divine knowledge). The fruit of each of the four branches is said to have a different taste. Everyone was very impressed by the beauty and huge size of this temple. The other two temples were at Mahabalipuram, built by the same rulers in the late 7th century. They are carved directly from rock; the one on the beach, called the Shore Temple, is particularly beautiful and has World Heritage status. The day finished with a superb show of classical, Indian film, and break dances, followed by an opulent dinner served on banana leaves eaten in the traditional way (fingers!). The last day of the conference started with a key note address by Dr Vuurde (Netherlands) entitled, ?Detection and ecology of phytopathogenic bacteria and health promoting bacteria at IPO, DLO'. This was a very well organised and complete exposition of the serological methods available and under investigation to detect and identify plant pathogenic bacteria. Just after lunch we had the last lecture by the chairman of the meeting, Dr Mahadevan (India), about ?Detoxification mechanisms in phytopathogenic bacteria'. After this address Dr Saddler (UK) presented the most recent changes in the names of phytopathogenic bacteria suggested by the Sub-Committee of Plant Pathogenic Bacteria of the International Society for Plant Pathology. The rest of the afternoon was specially dedicated to a valedictory function in honour of Prof Rangaswami, where around 10 speeches (of at least 15 minutes each!) were given by former colleagues, PhD students, and friends. The Conference finished with another superb cultural programme of religious classical dances and another dinner. I wish to acknowledge the travel grant awarded by BSPP that partly financed by attendance at the Conference and Praxis XXI (EU programme) that covered the rest of my expenses. Joao Pedro Luz 9th European and Mediterranean Cereal Rusts and
Powdery Mildews Conference The setting for the conference was the middle of a wood in a picturesque part of Holland at a congress centre called "De Blije Werelt" - "The Cheerful World". Over 160 scientists attended to present or discuss their work towards the understanding and control of cereal rusts and powdery mildews. The seminars were given over 4 days and over 80 posters were on display throughout the conference. The poster sessions and mealtimes gave participants ample opportunity to mingle and meet each other while enjoying the generous spread of food. Although billed as a European and Mediterranean conference, this conference drew participants from all continents except Antarctica (where, we gather, sowing strategies have meant that neither rusts nor mildew are considered to be a problem). Most of the participants from outside of Europe were interested in rusts, so giving a global perspective to the problem of rust control. In contrast, interest in mildew was confined to Europe and its environs - a lack of diversity that was perhaps countered by a greater diversity of approaches taken in the study of mildew. The opening address was given by Bob McIntosh, from Australia. He recalled the developments made in cereal rust genetics since his career began 36 years ago; from the gene to gene hypothesis, to the achievement of durable resistance and the cloning of resistance genes. Although progress had been great, he called out attention to the constant challenge posed by the continual evolution of the pathogens. He stressed the need for investment, the importance near-isogenic lines, and a need to "get to know gene interactions". There were 4 broad themes to the conference, and the first, "Molecular and Physiological Aspects of Host Pathogen Interactions" plunged us straight in at the cutting edge of research towards an understanding of the mechanisms involved in a pathogenic interaction. Henriette Giese (Riso, Denmark) started off by gazing into the crystal ball and predicting that soon a transformation system will be developed in Erysiphe graminis f. sp.hordei for direct assessment of the functions of the genes involved in infection. Experiments with biolistics already show GUS expression in conidia after hitting basal cells with DNA. Advances have been made with finding molecular markers and map based cloning and it will not be long before these genes will be isolated. Other talks covered the induction of defence genes, systemic resistance (B Barna, Budapest, Hungary), and genetics and mechanisms of mlo resistance (Jannie Atzema, Swiss Federal Institute of Technology, Switzerland; Michael Lyngkjær, Risø, Denmark) One approach that has been taken towards cloning a resistance gene was described by Beat Keller (Reckenholz, Switzerland). Two plant resistance genes which have already been cloned are protein kinases. Using conserved sequences in the resistance genes, the Swiss group probed Thatcher near isogenic lines ands identified a DNA band that only appeared in the line with Lr10. Further analysis supported the view that it could be Lr10. The gene has been sequenced, and it looks like a receptor. Although the gene product is the right shape, they were yet to show that the gene is involved in resistance, as opposed to just being "next door" to one. "Population Diversity and Dynamics" was the second theme, which began with a keynote presentation from Jan Parlevliet (Wageningen, The Netherlands). Breeding for resistance leads to rapid changes in host populations thus promoting the evolution of complex races of pathogens. He highlighted the important factors promoting variation in asexually reproducing pathogens and concluded that reproduction system is not a major factor affecting the accumulation of virulences. He ended with the outlook that, despite the large number of resistance genes which have become ineffective, the remaining ones can be used more effectively in combinations. Again in this theme, molecular biology reared its head, with several presentations using molecular markers to subdivide populations. Les Szabo (Minnesota, USA) cast the leaf rust phylogenies into doubt with a phylogenetic analysis of leaf rusts from North America and the Middle East, and showed that the main phylogenetic division was between old and new world rusts. This suggests that the present distribution of barley rusts in North America is due to a single colonisation, followed by diversification onto different hosts, rather than repeated colonisations by different species. A comparison of the phylogeny with that of the host could be interesting in determining whether the pathogens "track" their host's evolution, or whether they make "jumps" between different hosts. In the days of genetic engineering, this may have a practical application. If the rust evolves by jumping between host species, then transferring resistance alleles between species may not produce durable control, as we would already be aware that the rust is able to overcome the new resistance. At this time, half time was reached. The entertainments during the interval consisted of a meal at the Burgers' Bush, the tropical house of a zoo near Arnhem - a unique, if rather noisy venue. The dinner organisers were obviously concerned for our health, making us walk to different parts of the house to get to the next course. Apart from the animals, entertainments were provided by speeches. Roy Johnson gave a combined sketch/speech, in his normal ebullient and self effacing style, recalling his deeds and mis- deeds on and off the tennis court. At the next course another speech was given. Unfortunately, the microphone did not appear to work as intended, and the speech was inaudible except for two soundbites - "listen to me" and "we can communicate". Michael Lynkjær was astonished to be told that he should go and shake hands with the speaker, and receive an envelope. Only upon sitting down did he discover that he had won the poster prize. Indeed, only upon sitting down did he discover that there was a poster prize. The next day we were back to the science. In combating rusts, most effort is focussed on the major resistance genes. This constrasts with mildew where less effort is being put into researching major resistance genes, and instead other methods of control are being investigated. This dichotomy could be seen in the third theme to the conference, "Genetic variation for resistance in host plants". Most of the presentations were about rusts, and concerned the utilisation of major genes. Of course, there are more rust species than mildews, so this might not be surprising. However, there was a more even split between the pathogens when partial resistance was being investigated. It is accepted that most major genes will probably not provide durable resistance towards mildew, so alternative methods of control are being investigated. Because partial resistance is normally polygenic, breeding strategies become more complicated. Once more molecular markers spring to the rescue, with the advent of QTL (Quantitative Trait Loci) analysis. This is a method for trying to find genes affecting a quantitative phenotype by correlating the phenotype score with the presence or absence of markers. Two talks, by Rachel Hague (John Innes Centre, UK), and Xiaoquan Qi (Wageningen, Netherlands) outlined the progress made in trying to find QTLs for partial resistance towards wheat mildew and barley leaf rust respectively. An important issue is that of getting resistance genes into commercial cultivars, and a range of different approaches was covered. Chromosome engineering methods were described by two speakers for the transfer of rust resistance genes into cultivated wheat (Xiuzhang Xue, Wheat Research Centre of Shaanxi Province, China) and oats (Taing Aung, Winnipeg, Canada), while Sheila Kinane (University College Cork, Ireland) described mutagen induced mildew resistance in wheat. The suppression, in certain cultivars, of genes introduced from wild relatives with lower ploidy levels was the subject of a talk by R P Singh (CIMMYT, Mexico). Again there were many projects presented on posters, indicating that research into new sources of resistance and their effectiveness is extensive. Not until the final part of the conference did we finally talk about the whole point of studying rusts and mildew - "Epidemics and disease management". Most presentations were on the former, although there had already been some talks on mixtures - masquerading as population dynamics. The method of control that received most attention in this part of the conference was the use of fungicides. We got different aspects of their study - genetics (James Brown, John Innes Centre, Norwich), physiology (M Stark- Urnau, BASF, Germany) and population dynamics (Jörn Pons, Giessen, Germany). The epidemiology was very much a mixed bag - from modeling the effects of climate on overwintering in leaf rusts in the USA (M G Eversmeyer, Kansas State University, USA) to investigating the removal of rust spores from wheat leaves (L Geagea, INRA, France). The conference was a valuable and comprehensive summary of the current work bneing carried out on rusts and powdery mildews. In this aspect it was good because there was emphasis on current results, with many younger speakers presenting their results for the first time. The introductory overviews followed by shorter talks made the structure of each theme easy to follow and there was plenty of time to exchange ideas and make new acquaintances. The wooded surroundings provided a laid-back atmosphere, although somewhat isolated. The organisers had been adventurous and arranged several excursions, including a visit to the Flevoland polders, as well as the trip to the zoo. The organisers must be acknowledged for their thorough planning and attention to the needs of the participants. It was certainly an exciting meeting, and there was something in the conference for all those studying mildew and the rusts. Given that most of us specialise into a small subject area, it is nice to find out what others are doing to our beast of study, although in Henriette Giese's case this does involve shooting it! It will probably only be through concerted action on several fronts that mildews and rusts can be controlled, and conferences like this one give those working on specific diseases a chance to meet and their ideas to cross-fertilise. Bob O'Hara Katherine Steele Diagnosis and Identification of Plant Pathogens This international conference was held at the Institute for Plant Diseases which is part of the University of Bonn. There were about 250 delegates from more than thirty countries including quite a number from Eastern Europe. The first session dealt with general aspects of plant pathogen diagnosis. Emphasis was placed on the distinction between detection and diagnosis; detection methods indicate whether a particular pathogen is present or not, whereas diagnosis is the art of interpreting the nature of a diseased condition by examination and evaluation of symptoms and detection methods. Phytosanitary implications were also discussed; accurate pest risk analyses and robust diagnostic protocols are important for phytosanitary regulations and other political implications such as trade barriers. The infamous mad cow disease (BSE) was used as an example of a political and quarantine problem. The second session was on taxonomy and differentiation, which covered a wide range of techniques including serological methods, fatty acid analysis, electron microscopy and molecular methods. This wide range of detection means that very specific criteria are needed for the sort of diagnosis required for each plant pathogen, i.e. level of sensitivity, specificity and which part of the plant is tested (roots, seeds, leaves, flower or fruit) and the number of samples that need to be tested within a particular time period. There were also examples where a combination of techniques provided a more effective detection system, e.g. the use of PCR- ELISA for the detection of Phytophora fragariae (P Bonnants) and the use of immunocapture RT- PCR for detecting beet necrotic yellow vein virus (R Koenig). There were numerous examples of using rDNA sequences for taxonomy of fungal plant pathogens. John Bailey gave an interesting talk on the analysis of rDNA sequences for Colletotrichum, saying it should form the basis of a new taxonomy for this genus. Other speakers presented data on the diagnostic use of PCR, RFLP and species specific primers for ITS (internal transcribed spacer) sequences which have been an effective detection method and are used in routine diagnosis. It was clear from several of the presentations that there is a need for a large throughput of some pathogen tests. This may be achieved by automation of molecular techniques which excludes electrophoresis. Techniques such as PCR-ELISA, DIAPOPS (single phase PCR test in a microtitre plate), Taqman (a fluorescent detection system developed and patented by Perkin Elmer) and non-radioactive dot blot assays are being evaluated and optimised at various research institutes for ease of use, speed, cost, sensitivity and specificity. There were ninety poster titles included in the program but unfortunately quite a few were not presented at the Poster session. There was a time slot allocated each day for the posters which allowed plenty of time to study and absorb all posters of interest. An evening boat trip along the Rhine and a reception with the Mayor provided pleasant social activities for this conference. I am most grateful to the BSPP and NIAB for the funds which enables me to attend this interesting meeting. Emily J A Blakemore Spectroscopy & Optical Techniques in Animal and
Plant Biology Some remarkable techniques are now available for visualising and analysing biological material. This conference provided an excellent opportunity for delegates with a wide range of research interests to exchange ideas on the development and application of some of these techniques. In the opening session on nuclear magnetic resonance (NMR), delegates were shown impressive examples of the application of this group of techniques to both animal and plant systems. A Haase (Wurzburg) demonstrated how the new NMR spectrometers of high field strength can be used to overcome some of the difficulties normally associated with the method as an analytical tool - principally low spatial resolution and peak-to-background ratio. The new instruments are currently being used in his laboratory to measure flow velocities in xylem vessels, and regional distribution of metabolites (e.g. sucrose, glucose and amino acids) in a range of plant tissues. Richard Bligny (Grenoble) showed some elegant work in which NMR was used to study pH regulation and the effects of hypoxia in suspension cultures of plant cells. He showed how the ability to distinguish the position of a labelled carbon atom could allow dynamic processes such as respiration in living cells to be studied in real time. On the second day the topics were infrared and raman spectroscopy. Yves Marechal (Grenoble) showed how infrared spectroscopy can reveal not only the chemical composition of plant cuticles, but can also yield information on the degree of hydration and the type of bonding which exists between water and cuticular components. This technique could clearly have very interesting applications for those of us studying interactions between plants and foliar pathogens. Many interesting applications of fluorescence, phosphorescence and luminescence techniques were described on the following day, and Pierre Viallet (Perpignan) gave a particularly revealing overview of the advantages and limitations of these techniques. In the evening, delegates enjoyed a fascinating lecture by invited speaker Thomas Vogelmann (Laramy, U.S.A.), who began by showing that epidermal cells can act as lenses, and then demonstrated the use of micro light sensors to investigate pathways of light through leaves. The final sessions covered confocal microscopy and its applications to the study of signal transduction pathways, fibre optic microprobes, video microscopy, and other special techniques. In my own paper I presented work from the laboratory of Deri Tomos (Bangor) showing how turgor, osmotic pressure, and the full complement of solutes can be measured in individual plant cells. I am currently applying these techniques to a study of the interaction between barley and Erysiphe graminis. In addition to the talks, some seventy posters were presented, and we were given ample opportunity to get acquainted with other delegates over some excellent food and drink. The German enthusiasm for barbecues was not dampened by the weather - they simply moved the whole affair indoors! I would like to thank Rüdiger Paul and his associates for organising the conference, and the BSPP for contributing to my expenses. Paul Richardson The Brighton Conference - Pests & Diseases Pests & Diseases was the theme for this year's annual Brighton Conference, organised by the British Crop Protection Council. Technical and research delegates and commercial representatives flocked from all corners of the world to discuss topics as varied as precision farming, biotechnology, disease resistance, temperate and tropical pests and diseases and environmental and legislative issues. I estimate that there were over 1500 participants, attending more than 90 platform and poster presentations, two evening discussions and two exhibitions. There was a Trade Services Exhibition with some 160 exhibitors involved in supply of goods and services to the agrochemical industry, and a somewhat smaller Scientific and Educational Exhibition with 14 exhibitors, including UK Universities offering training in Crop Protection. A one-day pre-conference symposium investigated the opportunities for improved crop production by introduction of non- indigenous beneficial organisms. The main conference started with the Bawden Lecture, in which Allan Buckwell of Wye College gave an account of Europe's Common Agricultural Policy (CAP). The status quo has been described by the European Commission as not being a viable option, and policy changes are inevitable. Prof Buckwell envisaged a more integrated agricultural policy, not based on a system of price support for individual commodities, but encouraging rural and environmental development on a regional and local scale. In such a system, which could be in place in as little as 10 to 15 years, farmers would be competitive providers of foods but could also be contracted to provide countryside and environmental services. Inducing plants' natural resistance Ciba reported on their plant activator, which is sold in Germany among other countries under the trade name Bion 50. It affects a wide range of diseases, including Erysiphe graminis in cereals, but does not have any direct effect on fungi or bacteria. It induces the plant's natural defenses, for instance by increasing papillae formation and thus reducing leaf penetration. Plant activators or elicitors form the basis for novel crop protection agents that exploit a natural phenomenon in plants, referred to as systemic acquired resistance (SAR) by some speakers and systemic activated resistance by others. A separate platform session was devoted solely to this technology. Some researchers deemed the word "natural" inappropriate in this context, arguing that plant extracts concentrated in the lab were not natural anymore. Although compounds based on this technology will be subject to the same rigorous safety testing as standard crop protection agents, some concerns over safety and insufficient knowledge were expressed. Transgenic crops The new transgenic crops from the US, containing BT and glyphosate resistance genes were the subject of an evening discussion. A wish for specific labelling of transgenic crops to enable distinction from others was expressed. The platform presentations were generally of a high quality. Many delegates were impressed by M.G. Ford's presentation. Explaining how key properties, such as physical state, fluidity, adhesion and surface energy can be adjusted to increase pick-up of the active ingredient of pesticides from plant surfaces by target insects, as well as to optimise performance at reduced dosage, he gave his entire presentation straight from his laptop. The poster presentations ranged from flashy industrial posters to posters from UK research institutes, all of an incredibly high standard, to others that clearly did not have the facilities to compete on such a high level. The informative value of the posters was generally very good. Thank you for the BSPP Travel Award which partly financed this trip. The Brighton Conference was an excellent platform to exchange ideas with other like-minded researchers, but at a time of increasing specialisation in research it was also an opportunity to gain a wider appreciation of the field of crop protection. Brighton itself was an ideal place for a conference. It boasted impressive architecture and the flair of a seaside resort, and when it came to socialising in restaurants and pubs in the evenings, delegates were truly spoilt for choice. The only thing we could have done without, were the gale-force winds which threatened to blow delegates off their feet, and made walking along the seafront, where the conference centre was located, a risky undertaking. Ragnar Weissmann The weather was pleasant on the first day, but constant drizzles and blustery winds on the following days forced most conference participants to stay in-doors and listen attentively to the proceedings! The posters covered various areas such as biological control, mode of action of pesticides, epidemiological and physiological studies and environmental fate and effects concisely. The Scientific and Educational Exhibition held in the Brighton Centre was informative. New chemicals The session on "New compounds, formulations and uses for disease control" presented new developments in chemicals and micro-organisms for control of crop diseases. The emphasis was on novel active ingredients. DPX-JES74, a broad-spectrum fungicide with a new mode of action from DuPont was useful against downy mildew of grape and various dieseases on tomatoes, potatoes, wheat and barley. DowElanco offered DE-795: a novel fungicide for the control of powdery mildew in cereals which works by inhibiting appres soria formation. Ecogen Inc. reported Ampelomyces quisqualis: a new biofungicide, to control powdery mildew in grapes, pome fruit, strawberries, vegetables, ornamentals. It is formulated as water dispersible grandules which are stable for 3-4 months at room temperature. The product can be used up to the day of harvest. The plant activator CGA 245704 from Ciba-Geigy induces the natural defence mechanism in plants it activates plant resistance, inhibiting certain funal stages in e.g. Peronospora in tobacco. Low rates (12- 30 g ai/ha) give adequate protection in cereals, tobacco, rice, bananas and vegetables. This compound attracted quite a lost of attention due to its unusual mode of action. Disease control in fruit and vegetables The "Pests and diseases in viticulture - current problems and solutions" session offered solutions ranging from the conventional use of agrochemicals to the forward-looking breeding and gene manipulation techniques. Powdery mildew causes the most damage to grapes in North America. Bunch rot, a vartiety of insects and viruses also attack the plants. The speaker offered various solutions to some of these problems. Another speaker on the control of bunch rot cited resistance and residue problems. He suggested alternating fungucides with different modes of action with one spray per season. In addition to integrated control strategies, forecasting techniques and novel, non- chemical methods of control, the session on "Advances in arable crop protection" covered strategies for the management of pests and diseases, in line with our increases understanding of biology and epidemiology, economic and environmental pressures and legislation. Pest and disease control in fruit and vegetables was targeted at both maintenance of yield and quality. The session dealt with a range of topics of current interest and importance of researchers and growers. The control of Trichoderma harzianum. a weed mould of mushroom cultivation was of particular interest. The fungus colonises the compost and causes disease in the mushrooms. Fungicides such as procloraz had been used in the post, but BavistinR (carbendazim) was now providing more effective. Cultural control and inegrated crop management are both based on the principle of crop management practices which made the crop environmental less favourable for pest and disease colonisation, reproduction, survival and dispersal, while favouring population growth of natural enemies. The use of crop management techniques were addressed in terms of pest and disease control and conservation of natural enemies. Pest and disease prediction, host plant resistance, novel pesticides, biological and cultural control methods, and attempts to integrate these in the protection of horticultural crops were covered in the session on "Advances in horticultural crop protection". Prokaryotic pathogens Plant pathogenic prokaryotes (bacteria, including phytoplasmas) cause a wide range of diseases and severe crop losses in tropical areas. However, the resent advances, in the rapid and accurate diagnosis of such diseases using molecular techniques, and on the scientific basis for disease management give fresh hope. The interactions between Pseudomonads and Phaseolus beans and the exploitation of genotype mixtures in subsistence agriculture was well covered. The bean grows in the cooler parts of East Africa. The most imortance disease is angular leaf spot. Anthracnose, halo blight and monoculture; farmers in Tanzania seem to be well aware of the advantages of planting certain bean varieties in certain seasons, and therefore reducing levels of disease. I am very grateful for a BSPP travel grant which partly financed my attendance at this conference. Irene Mutinda 8th Annual Congress of the Postgraduate Institute of
Agriculture This Congress was organised by the Postgraduate Institute of Agriculture (PGIA) of Peradeniya University and was held at the Plant Genetic Resource Center near Kandy in the Sri Lankan hill country. The impressive opening ceremony, on 21st November, started with a lively rendition of the national anthem and continued with due ceremony involving the lighting of an elaborate 6 ft. high oil lamp by all of the chief organisers and guests of the Congress accompanied by traditional Kandyan drummers. Several speeches were made to thank the organisers of the Congress and set the scene for the following paper presentations. The theme of the introduction was concern for the state of Agriculture in Sri Lanka. At present the country cannot produce enough rice and other foodstuffs to meet the demand of its population. At the same time imports from Thailand, China and India are drying up. There was a strong emphasis on developing research directly relating to improved field production of crops while preserving the environment. The presentations proper commenced after coffee and two parallel sessions were run over two days. The session topics covered all aspects of agriculture including: agronomy and crop experimentation, agricultural communication, soil science, genetics and plant breeeding, irrigation and remote sensing studies, biotechnology, natural resource management, plant physiology and post harvest technology, animal science and aquaculture, and last, but not least, pest disease management. The standard of paper presentation was high and the participants should be congratulated especially as for many of them it was their first public presentation of their research findings (the criteria for inclusion in the conference was completion of a higher degree no more than two years previously). The majority of participants were from Sri Lanka but representatives from India, Australia, Switzerland, Japan and the UK were also present. The two invited speakers were Prof C Wenk from the University of Zurich ("Modern biotechnology in animal nutrition for a higher productivity with lower pollution") and Dr Anna L Snowdon from the University of Cambridge ("Forensic post harvest pathology in the context of ships' cargoes of fruits and vegetables"). Dr Snowdon gave a thoroughly interesting and entertaining presentation including some case studies. As she pointed out the word "forensic" pertains to law and the results of her investigations of spoiled cargoes are used in legal wrangles over "who is to blame". One case example studied the spoilage of a shipment of bananas caused by the ethylene gas released from rotting oranges stored in hold below the bananas. The law suits went on for more than three years and may still be going! For me this was an excellent forum for the presentation of my work on a fungal pathogen of a tropical crop (witch's broom disease of cocoa in South America). The hard work I had put into preparing the paper and slides was rewarded by being judged the best presentation in the session (an award was given for each session). The atmosphere of the entire Congress was of enthusiasm with researchers keen to discuss their own and others work. Congratulations must be extended to Dr Colin Peiris who bore the ultimate responsibility for the smooth running of the Congress, and to all of the committee members who had obviously put much effort into making the whole meeting a resounding success. After attending the PGIA Congress, I visited the University of Peradeniya Crop Science Department where I was welcomed by Ms Renuka Karunagoda (lecturer in botany and plant pathology) who extended true Sri Lankan hospitality to me. I stayed with Ms Karunaoda and her family in the beautiful tropical setting of the University campus and was encouraged to experience much of the local culture and cuisine (including the wonderful range of curries available for breakfast, lunch and dinner!) The students at the PGIA could not have been more friendly and organised a day trip for overseas participants to visit the impressive Temple of the Tooth in Kandy and the nearby Pennawela elephant orphanage. Later I travelled with some of the students to visit the Uda Walawe National Park and to climb the awesome Sri Pada Mountain. During the latter part of my stay I travelled north to visit Mr Ranaweera Banda (a contact in the Government Department of Agriculture) whose family again extended the then familiar, Sri Lankan hospitality. Mr Banda gave me an interesting insight into the problems of irrigation dependent agriculture. He is also involved in research into the mysterious chili narrow leaf disease affecting producting of this crop in Sr Lanka (no meal in Sri Lanka could be served without chilies!). Research has not yet determined the cause of this disease, whether pathogenic or physiological, and much interesting research lies ahead. I hope that my participation in the 1996 PGIA congress will help to maintain links with researchers in Sri Lanka and will encourage others to support the PGIA's efforts to raise international awareness of their research both at home and overseas. I would like to thank the BSPP and the University of Nottingham Plant Science Department for help in funding my travel to the PGIA congress and allowing me to maintain contacts in such an amazing, beautiful and diverse country. Fiona Wilson Unlocking the Future These are my personal impressions of this well organised and extremely stimulating conference. Fortified by a substantial lunch, I plunged into the practical and tutorial sessions on the first afternoon. I floated in and out of CABI's forthcoming CD-ROM, "Compendium of Crop Protection" (at present based mainly on SE Asia), then explored the hidden layers of neural networks before surfacing to surf the Net. The next day in his Presidential address, Peter Scott gave a fascinating display of the power of computer chips. I was even more amazed by his ability to continue talking rationally through a succession of computer crashes. Through it all we sensed his enthusiasm for his recently adopted subject - computers really are fun! In his eye-opening keynote speech for the Systematics Association, Professor Sneath explained a lot when he admitted that "species, like beauty, is in the eye of the beholder". This enabled Frank Bisby to give us a bird's eye view of species identification in the third millennium. We will have descriptions of 1¾ million known organisms at the touch of a button. Simon Jones told how this would operate with data warehouses interlinking data from many sources; the data can then be mined for nuggets of information. But will the information be entirely accurate? Ian Smith introduced the uncertainty principle in his attempts to keep pathogens in their place: they may or may not be in places where they are officially stated to be! The misidentification of many species inColletotrichum was cited by John Bailey when he highlighted the need to record accurately the origin of organisms. Uncertainty also pervades the field of molecular genetics: Stephen Oliver queried whether around 50% of the yeast genome really was redundant; it could have a quantitative contribution to make and we should watch this space. On the application of computer-based species identification, Professor Pankhurst would not hanky-panky with any database other than a relational one and the only proper format was the DELTA format. In this system R Fortuner likes to pre-digest (his word decompose) whole organisms to molecules via their component parts (systems, organs etc.) and predicts that the prototype NEMISYS (for nematodes) will blossom into GENISYS (for general use). On the other hand, Mike Dallwitz is keen to feed the system interactively with whole butterflies and grasses. Will this resucue us from a looming biodiversity crisis, beset by declining taxonomic expertise and problems in handling the flood of information? Yes, according to Peter Schalk, his software (Linnaeus II) will take the world's biodiversity on board (a kind of Noah's Archive?). All this must depend on archiving high quality images. Philippe Blaise gave a practical example of how useful superimposed images can be in plant pathology; a Geographic Information System helped to establish that canker of plane trees was spread by pruning, not by insects. As if to illustrate his theme that "keys without pictures don"t work', D Roberts struggled manfully to describe invisible dinoflagellates through every speaker's worst nightmare, a projector failure. Will computerised images be more reliable? Within a very busy poster and hands-on demonstration session, Charles Lane showed us how images could be captured and licked into shape. Mike Jeger brought us back to basics in his Garrett Memorial Lecture with the concept of "basic reproductive number" helping to decide whether to rogue or not to rogue and with a potential refurbishment of Garrett's inoculum potential to improve disease management. When it comes to teaching plant pathology, Gail Schumann reinforced a pervading theme that "a picture is worth a thousand words". In the APS Plant Disease Video Image Resource, she has a videodisc of nearly 10,000 images at her fingertips. Pierce Jones' talking pictographs get the message across to workers about the hazards of chemicals and Zuo Rui Shen's images spread the importance of plant quarantine insects amongst China's plant health inspectors. Terry Steward reminded us that teaching should not be all work and no play; much fun can be had in turning Diagnosis into an adventure game. By all accounts Geoff Norton's software products for diagnosing and managing pests and diseases in Australia are great fun. Bugmatch has moving images of caterpillars and a magnifying glass to enlarge any part of the image and LucID has a builder for easy key construction. Every game involves a winner which the judges of the P H Gregory paper reading competition found to their cost; they agonised long and hard to pick one from a set of five excellent papers. In concluding orations, Stephen Black more, as Chair of the Systematics Association returned to the theme of archiving biodiversity before we lost it and Peter Cochrane of BT echoed Peter Scott's introduction on the incredible pace of computer progress. How does the human brain cope with computer power more than doubling every 18 months? He resented being "silicomorphized" and instead insisted that IT should be made people-compatible. He showed us a glossy advertisement of a sports car selling in 1970 for $8,000. It was another eye-opener to be told that if these cars had kept pace with computer development, they would now cost 80 cents and travel at Mach 6! Thank goodness they haven't kept pace, otherwise six of them would now fit on the head of a pin! The venue was interesting; a modern university within sight of Canterbury Cathedral. It also exercised delegates' orienteering skills when navigating between lecture theatres. The excellent Presidential dinner was meticulously planned by Peter Scott down to the provision of a very acceptable local white wine. His after-dinner speech complete with renderings from Chaucer's "The Miller"s Tale' reminded us that there was fun even before the age of computers. It remains for me to thank the organisers and contributors for all their hard work and last but not least the BSPP Travel Fund for assistance towards my travel costs. Roger T A Cook
|