BSPP News Spring 1999 - Online Edition

The Newsletter of the British Society for Plant Pathology
Number 34, Spring 1999

People and Places

University of Hertfordshire

Dr Avice hall, an academic at the university for nearly 30 years, has been elected honorary secretary of the British Society of Plant Pathology. Horizon recently caught up with Avice to discuss her new responsibilities, her career and her lifelong interest in plants.
The foremost society for the study of plant diseases in the UK, the British Society for Plant Pathology has over 80 members throughout the world. The work of the organisation is extremely relevant to everyday life, says Avice, principal lecturer in environmental sciences: "Something the layman might not appreciate is that 10% of the field of any given crop is lost before harvest because of plant diseases."

From the Potato Famine of the 1840s to Britain becoming a nation of tea drinkers because of afflicted coffee plants in Sri Lanka, some of the world's most significant historical and cultural developments have occurred because of plant diseases,she added.

Avice describes herself as "at heart a botanist, but professionally a plant pathologist" who carries a hand lens with her always. "I originally had an interest in diseases affecting cereal crops - and I have one in the Third World - because of their importance to foor production and food security on a world
scale."

More recently she has also conducted research into issues concerning horticultural crops, for example the impact of powdery mildew on rhododendrons and black spot on roses. "The overall market value of rhododendrons in the UK last year was over £12 million and the UK export of roses alone was worth nearly £700,000, so research in these areas is essential to the future of an industry which is important financially as well as culturally.

This research complements the growing movement towards controlling diseases with a minimum use of pesticides. "At the moment, horticultural crops which are sold for people's gardens are often cultivated in a manner highly dependent on pesticides," says Avice. "Growers face a situation in which plants would be so disfigured without the use of pesticides that they couldn't be sold or that, once purchased by the household gardener, the plant is so disease-ridden that it soon dies."

Avice says that much of her career has involved encouraging and motivating others. "That's a large part of what I will be doing as honorary secretary of the British Society for Plant Pathology, working to affect policy-making regarding plant pathology at a variety of levels, from Government to higher education."

A so-called "Brockett Baby", Avice was born at Brockett Hall, which was used as a maternity hospital during the war. Aged 53, she lives in St Albans where she is an active member of a local church and runs a youth club in her free time.

So, given her professional interests, does Avice have a beautiful garden? "Well, my mother's garden is stunning, but I don't think my own garden is beautiful. I would like to have one though - maybe that's my retirement project!"

Reproduced with minor alterations from Horizon, the University of Hertfordshire's newspaper, by kind permission.

 


ADAS

Dr Mike Griffin, who is well-known to many members of BSPP, has been appointed ADAS Director of Research. Aarun Naik has joined us at Boxworth and Giles Budge at Arthur Rickwood.

The 7th International Congress was well attended by ADAS staff with Tim O'Neill being the session organiser for "Recent developments in the control of botrytis in horticultural crops". This session proved popular, indicating there is still an interest in non-molecular pathology!. Neil Paveley gave a keynote paper on the "Integration of epidemiology, cropprotection and physiology as a biological basis for decision support". Rosie Bryson presented a paper on an "Opportunity for remote sensing in wheat to explain variation in yield response to disease by estimating radiation interception by crop canopies". Posters were presented by Peter Gladders on "Appropriate dose strategies on winter oilseed rape canker control", Tom Locke on "Spray regimes on captan residues in apples" and by Caroline Young on the "Effects of cropping practice, soil type, sclerotial position and environmental conditions on Sclerotinia sclerotiorum of field grown lettuce". I am very grateful to Caroline for `manning' my poster on the "Effect of Sclerotinia sclerotiorum inoculum, weather conditions, cultivars, plant densities and fungicide timing on stem rot and crop yield of oilseed rape". (I was on sick leave throughout the summer and very disappointed that I missed attending the Congress and the many overseas researchers - at least I have fond memories as a student of the First Congress with one volume of, only!, 450 abstracts on my bookshelf.)

Tim O'Neill visited Jerusalem in August (very hot!) for the Sixth International Mycology Congress, and presented a paper on "Integrated cultural, environmental, and biological control of grey mould in greenhouse salad crops" and also undertook a HDC-funded study tour of Holland to investigate cucumber thick root. Presentations including work on tomatoes, cucumbers and cut flowers were made at various national grower conferences.

I attended the 10th International Sclerotinia Workshop in Fargo, North Dakota, USA, in September, an account of which is given in the "Conference and Travel" section of this issue of BSPP News.

In November, Peter Gladders, Tom Locke and David Jones were session organisers at the Brighton Crop Protection Conference - Pests and Diseases, and David Lockley presented a poster on the "Management of Stagonospora nodorum on winter wheat in south west England."

Fen Beed gave an account of "Yellow rust, sunshine and yield loss" to the Cambridge Mycology and Plant Pathology Club in December (reported in "People and Places")and Peter Gladders gave a presentation on disease control and reduced fungicide inputs at the Talisman/Scarab Conference at Churchill College, Cambridge.

John M Ll Davies, ADAS Terrington


IACR - Long Ashton

1998 was a year of many changes, with immigration, mass migration, and dispersal all affecting the pathology gene pool. April saw a significant increase in the size of the Molecular Plant Pathology Group due to a merger with the Fungicide Mode of Action and Resistance Group led by Derek Hollomon. This change mainly reflects the convergence of research on fungal pathogenicity and potential fungicide targets through common approaches utilizing molecular genetics and biological imaging. The core research continues to focus on major pathogens of temperate cereals, such as Septoria, Stagonospora, Erysiphe and Tapesia species, although work on downy mildews and Colletotrichum still features. The long wet summer ensured plenty of disease to look at. An important development during the year was the arrival of our new confocal microscope, funded by a grant from the BBSRC Joint Research Equipment Initiative, which provided a new dimension to our imaging facilities, as well as hours of fun with red and green spectacles. Richard O'Connell is supervising this new facility.

New faces in the group include Sabine Perrone, working with Paul Bowyer as part of the EU CEREPAT network on eyespot disease of cereals, Nicola De Luca, another EU-sponsored postdoc working on pathogenicity in Botrytis, joint with the Department of Biochemistry, University of Bristol, and Jo Ayriss, a BBSRC-CASE student joint with Zeneca Agrochemicals, who joins the Septoria team. During the year Andy Payne and Sally Monnington both submitted their theses, and successfully obtained, their PhD degrees. Other departures include Andy Bailey, who is moving in April to a lectureship in the School of Biology, University of Bristol. We expect to see him back here regularly on a number of collaborative ventures.

During the year IACR launched a Fellowship scheme to forge stronger links with Universities and I am pleased to report that Chris Caten, Birmingham, and Sarah Gurr, Oxford have both accepted invitations to become Fellows linked to the Molecular Pathology Group. We already have common interests in cereal pathogens as well as some joint projects, and we hope to develop these further.

Visitors from overseas continue to make an important contribution to the work of the group. Currently we have Yasunori Tokunaga from Ube Industries, Japan, studying systemic acquired resistance in barley, June Simpson, from the Centro Investigaciones y Estudios Avanzados, Mexico, working on pathogenicity mutants in Colletrotrichum lindemuthianum, and Olu Latunde-Dada, a Nigerian scientist supported by a Royal Society Developing World Fellowship. Olu continues to unravel the complexity of anthracnose pathogens on cowpea, as well as rescuing long-lost cultures from the -80 freezer. Links with South Africa initiated through the UK/SA Science and Technology programme have continued to develop. John Lucas attended the 1998 meeting of the South African Society for Plant Pathology Congress in the Drakensberg, as well as visiting Stellenbosch, and Maneshree Jugmohan, a PhD student from the University of Durban Westville is now with us working on molecular variation in different pathotypes of Peronospora parasitica. One further benefit of such international collaboration is the culinary skills our visitors bring (is molecular biology really a branch of cookery?). Most exotic dish of the year was most likely Cuitlacoche, galls of maize smut consumed as a delicacy in Mexico. These are best enjoyed with a liberal shot of tequila.

1998 was of course a big year for conferences, and Long Ashton pathologists were in evidence at several of them. Paul Bowyer and colleagues went south to Leon, Spain to the European Conference on Fungal Genetics. John Lucas and Andy Bailey both went west to Athens, Georgia, ostensibly to attend the Second International Symposium on Fungal Genomics, but also to pay homage to the birthplace of the B52s and REM. Derek Hollomon and John Hargreaves went to the IUPAC International Congress on Pesticide Chemistry in London. The mass exodus to Edinburgh marked the final demise of the group travel budget, but did not deter further expeditions to Jerusalem (IMC6, Richard O'Connell, partly funded by a BSPP travel grant) and Fortaleza, NE Brasil (Brazilian Congress of Plant Pathology, John Lucas). The latter ensured a good supply of cashew nuts and cachaca for Christmas.

David Royle's retirement during August resulted in a number of realignments of the Crop Pathology Group. Ming Pei, Tom Hunter, Roy Coker and Carmen Ruez Martinez all moved into the Genetic Diversity Group, now led by Angela Karp. The work on willow rust will continue as before, while studies on genetic diversity in Septoria, including the role of the sexual stage in epidemics, is now closely integrated with other research utilizing molecular markers in populations. Darren Lovell, Fiona Store and Pierre van Peteghem moved into the Crop Ecology and Management Group, where they will continue studies on the influence of weather and crop factors on Septoria epidemics under the guidance of Vic Jordan at LARS and Bruce Fitt at Rothamsted. And 1998 turned out to be a vintage season for S. tritici.

The IACR year ended with the retirement of our outgoing Director Ben Miflin, and the arrival of our new Director Ian Crute, who, rumour has it, is a plant pathologist! We look forward to more lively times ahead.

John Lucas

 


Cambridge Mycology & Plant Pathology Club

President: Henry Tribe

`Yellow rust, sunshine and yield loss' was the subject presented by Fen Beed of the University of Nottingham and ADAS Boxworth on Friday, 13 November1998. The challenge was to explain site and seasonal variation in yield loss caused by diseases in winter wheat. Yellow rust on the susceptible winter wheat cultivar Slejpner was the disease system used. Mobile shading covers were a key treatment and were used to manipulate light interception during various stages of yield formation from the first node stage to grain maturity (GS 31-87). These experiments tested physiological hypotheses about when key phases of canopy expansion, grain number, grain size and grain weight were determined.

Shading treatments were used on bright days (>250 MJ/m2) to reduce light to the equivalent of a dull day (on dull days the shades were not used). It was not possible to review all the results during this presentation, but there was clear evidence that yield loss per unit disease did vary and this could be explained by differences in `source' and `sink' capacity. Low levels of radiation can increase the sensitivity of the crop to disease. This means that predicting the response to disease control cannot be achieved simply by looking at the crop. Some knowledge of intercepted radiation, grain number and soluble carbohydrate reserves is needed to improve prediction of yield loss and optimisation of fungicide treatments. David Kenyon, NIAB, Cambridge spoke on `Seed-borne diseases - thresholds, testing and treatment' on Friday, 27 November. It is clear that seed tests are valued because they enable some problems to be avoided and informed decisions to be made about the need for seed treatment. The occurrence, symptoms and importance of the major seed-borne diseases of cereals was reviewed. Fusarium spp. have been particularly widespread on wheat in 1997 and 1998, contrasting with the previous three years when few seed stocks were rejected because of Fusarium. Bunt is common in wheat, although most stocks remain below treatment threshold. Barley leaf stripe generally affects only a few stocks seriously and the recent development of a PCR test at NIAB now enables such stocks to be identified quickly. The importance of seed-borne diseases was also highlighted by the first record of flag smut on wheat in the UK this year. The exploitation of new techniques will hopefully enable this key area of disease control to be manipulated with greater efficiency.

Members were saddened to hear that Margaret Keay had died in early November. Margaret was the first Secretary of the Club way back in October 1950 and there are many happy memories of her activities in Cambridge and Africa, not to mention regular attendance meetings over many years.

For further information about meetings contact Peter Gladders, ADAS Boxworth. (01954 268230)

Peter Gladders

 


Scottish Mycology and Plant Pathology Club

The autumn meeting of the club took place at the Scottish Agricultural College in Edinburgh on 30th September 1998. In the absence of Fiona Burnett, who was on maternity leave, the local arrangements were organised by Rob Harling and Mark Hocart. There was a good turn out as usual with over 40 club members present.
The first presentation was given by Nick Read of Edinburgh University who presented the latest observations of Spitzenkörper dynamics and endocytosis in living hyphae captured by confocal microscopy.

Paul Matthews, also from Edinburgh University, then described approaches to controlling zoosporic fungi in recirculating irrigation systems using calcium ion levels to modify zoospore behaviour. Glyn Nelson (Edinburgh University) continued the calcium theme in a talk on calcium measurement in Aspergillus using the recombinant aequorin gene system to quantify the cation inside living hyphae.

Lucy Harrier (SAC, Edinburgh) described the isolation of genes from arbuscular mycorrhizal fungi and the use of the clones genes in studies of fungal biology and in
analysis of the symbiosis between fungus and host plant. The afternoon session opened with Adrian Newton (SCRI) explaining the relationship between the number of component genotypes in a varietal mixture and Rynchsporium severity, yield and malting quality in barley. Then Neil McRoberts, (SAC, Auchincruive) completed the offered paper session with a talk on decision making and diagnosis in disease management in which he compared the approach to diagnosis and treatment decision making used in the medical sciences to that used by plant pathologists.

The oral papers were complemented by a poster display during the breaks and over lunch in which 10 posters were presented. Topics ranged from the molecular detection of Nectria galligena in apple wood and the influence of fungicide use on morpholine sensitivity
of barley powdery mildew to molecular phylogeny of oomycetes and organelle dynamics, with several posters relating to research described in the offered papers.

Finally there was an open forum for discussion of recent conferences. Nick Read summarised the recent International Mycological Congress which he attended in Israel in 1998 and there was an opportunity for club members to give feedback on the International Congress for Plant Pathology held in Edinburgh in August 1998. Comments, congratulations and criticisms were sent on to the ICPP98 organisers for their consideration and to provide helpful advice to the organisers of the 8th Congress.

Mark J. Hocart, SAC, Edinburgh 


Central Science Laboratory

Since the last Newsletter the staff of the Plant Health Group have had their fingers in many pathological pies. A joint project, funded by the Horticultural Development Council, into Cucumber Root Mat (CRM) disease has just completed its first year's work. Those involved are David Stead, Simon Weller (CSL), Tim O'Neill (ADAS), Martin McPherson, Andy Jackson (HRI) and Derek Hargreaves (Horticultural Consultant). CRM first appeared in UK cucumber crops in the 1970s, in straw and soil bed crops, but then disappeared before reappearing in 1993 - this time in crops grown in the rockwool medium.

Typical symptoms are extensive root proliferation, leading to swollen propagation cubes and, in severe cases, loss in yield and quality. Rhizogenic Agrobacterium strains had always been associated with the disorder but no conclusive proof of the association had been obtained. Rhizogenic Agrobacterium strains possess an Ri-plasmid, similar to the Ti-plasmid associated with crown gall disease, that genetically modifies infected cells making them more sensitive to endogenous growth hormones. A survey during the autumn of 1997 of UK cucumber crops showed that there was a statistically significant correlation between affected crops and the presence of rhizogenic Agrobacterium biovar 1 strains. A glasshouse experiment set up at CSL where cucumbers were inoculated with rhizogenic Agrobacterium biovar 1 strains fulfilled Koch's postulates. Since this proof was obtained work has begun on the epidemiology and control of the pathogen.

The Crop Disease Assessment Team has been out and about. Nigel Hardwick attended an EU Concerted Action meeting held at Uppsala in September on "A European network for development of an integrated control strategy of potato late blight" and Judith Turner attended an EU COST action meeting held in Athens in October on "Agriculturally important toxigenic fungi".

A new MAFF SAPPIO-LINK project, co-ordinated by Dr John Elphinstone and involving Dr Tim O'Neill from ADAS, has just commenced and will investigate methods for the detection and control of the potato brown rot bacterium (Ralstonia solanacearum). Standardised and automated DNA and RNA amplification methods will be developed and used to detect viable populations of the quarantine bacterium in industrial potato processing or pre-packing waste and domestic sewage. A range of current and novel waste treatment methods will then be validated to ensure elimination of the risks of pathogen spread via watercourses to agricultural land.

The project will combine current knowledge of the biology of the bacterium with expertise of potato agronomists, growers, processors, pre-packers and retailers, the water industry and waste treatment specialists. A steering group chaired by Richard Harris of the Potato Processor's Association, including their representatives and those of the British Potato Council, MAFF and the Environment Agency will assist in technology transfer and exploitation.

Unwanted aliens!

And last but not least, a note from Peter Sellar to raise public awareness. We are reminded that CSL is the quarantine diagnostic laboratory for the Plant Health and Seeds Inspectorate of MAFF. This
involves the identification of pests and diseases on the whole range of plants and plant materials moving in both national and international trade. Over 20,000 samples are sent in for laboratory examination each year; these are taken from consignments being imported, exported or moving within the EU under a plant passport. When quarantine pests or diseases are found, it is CSL's duty to recommend appropriate eradication or containment measures to prevent establishment of these organisms in the UK.

New or unusual occurrences such as the 1998 UK records of Urocystis agropyri on wheat (flag smut) or Kabatiella zeae on maize (eyespot), are referred within CSL for an assessment of risk, in order to evaluate the significance of any particular finding and recommend whether or not statutory action is appropriate. Readers are reminded that findings of pathogens (and pests) not previously known to occur in the UK should be reported to MAFF (for England and Wales), Plant Health Division, Foss House, York, Y01 7PX, SOAEFD (for Scotland), Pentland House, Edinburgh, EH14 1TY or DANI (for N. Ireland) Dundonald House, Belfast, BT4 3SB.

We look forward to the next round of new or unusual records with baited breath!

Claire Sansford 


Horticulture Research International

Professor Ian Crute left HRI in January to become Director of IACR. Ian made an enormous contribution to HRI and to international plant pathology in his 25 years at HRI and will be missed, but we wish him every success in his new post. On 1 April we look forward to welcoming Professor Mike Wilson of SCRI who will become HRI Director of Science, based at Wellesbourne.

Mycology

In October Geoff White visited Australia and New Zealand, to review the Australian National Carrot Cavity Spot Programme run by Elaine Davison and Alan McKay. The project has the aim of reducing losses due to cavity spot in the lucrative crop for export to South-East Asia and Japan. The project is funded by HRDC and will involve close collaboration between science and growers, very much on the model of Horticultural Development Council projects in the UK. Geoff also spent a week in New Zealand with Alison Stewart at Lincoln University, and with John Marshall at Crop and Food Research Ltd. Their interests in biocontrol and detection of soil-borne fungi are very close to those at Wellesbourne, and offer great potential for collaboration.

Barry Wright joined Welles-bourne to work with John Whipps and Hugh Rowse on a HortLINK funded project on "Application of beneficial microorganisms to seeds using priming techniques". Dan Funck Jensen arrived in November from the Royal Agricultural and Veterinary University, Copenhagen, Denmark to work with John Whipps for a year on biological control of Pythium and other pathogens in soilless growing media. Emma Coventry has recently arrived from Aberdeen to work with Ralph Noble and John Whipps on control of Allium white rot.

Alex Collins is a new PhD student at HRI-W working on a molecular approach to understanding host specificity, gene flow and the species concept in plant pathogenic Verticillium species with Dez Barbara and David Parry. This project complements the work of another new PhD student, Adriana Soares, who will focus on mechanisms of resistance to Verticillium in strawberry, supervised by David Parry (HRI-East Malling).

Bacteriology

Sarah Holcroft is a new PhD student at HRI-W working on the biology and epidemiology of Xanthomonas leaf spot of ivy with Steve Roberts. Steve will also soon start work on a new MAFF project on bacterial canker of cherry.

Virology and phytoplasmas

Dr Michael Clark retired in September after 26 years service at HRI-EM. Mike's work on virus and phytoplasma diagnostics had enormous international impact. Mike has been appointed an HRI Emeritus Fellow so his association with HRI will continue. Dr Yiguo Hong has joined the Molecular Phytoplasma team, working with Dez Barbara and David Davies. Yiguo has a background in molecular virology. Dr Melissa Kirkby has started at as a new molecular plant virologist working on PCR detection and characterisation of apple tree viruses with Tony Adams.

Clare Edwards is a new PhD student working on molecular analysis and transgenic resistance to viral diseases of Petunia. Clare is based at the University of Bristol working with Gary Foster, and is
co-supervised at HRI-W by Peter Mills and Nicola Spence.

Dr Paul Hunter joined John Walsh's group to work on the involvement of viruses in the internal breakdown of stored white cabbage and on variation in turnip mosaic virus (TuMV) in natural wild populations of brassicas.

Several HRI staff visited China in April 1998 for the first meeting of their EC funded project on the genetic improvement of brassicas for TuMV resistance. In China where more than 20% of the world's population live, brassicas are a staple food; Chinese cabbage alone comprises 25% of the total vegetable production in China. TuMV has been shown to be the most important and damaging disease of Chinese cabbage, followed by soft rot.

Dr Meena Muthumeenakshi joined Dez Barbara and John Walsh's groups in October 1998 to work on the genetic modification of B. oleracea for resistance to turnip and cauliflower mosaic viruses.

Diagnostic services

Dr Martin McPherson, HRI Stockbridge House, has recently been appointed to lead the HRI/HortiTech Diagnostic Services Business Unit. Martin will streng-then diagnostic services offered in HRI to provide customers with diagnostic services to suit their specific needs. Mrs Joscelyne Bigham also recently started in diagnostic services at HRI-W to carry out commercial virus testing and soil testing for cavity spot of carrots.

Virtual Horticulture

Several new HRI Plant Pathology Web pages went live in January - please visit them at www.hri. ac.uk. HRI have produced a CD-ROM grower reference manual on Brassicas, known as HORISTM, which includes sections on viral, bacterial and fungal pathogens of horticultural brassica crops.

Nicola Spence, HRI Wellesbourne