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BSPP News Autumn 2000 - Online Edition
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The Newsletter of the British Society for Plant Pathology
Number 37,
Autumn 2000
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Conference
and Travel Reports
5th
European Conference on Fungal Genetics
Arcachon,
France : 25-29 March 2000
The
5th European Conference on Fungal Genetics was held in Arcachon on the
Côte d’Argent, a long stretch of coastline which, at 200km, is the
longest, straightest and sandiest in Europe. The conference began with
a tour up the Pyla Dune, the highest sand dune in Europe, for which we
were fortunate enough to enjoy two of the only sunny hours of the meeting.
The view from the top, overlooking the bay of Arcachon and its famous oyster
beds (whose produce we were due to sample later in the week), was superb.
Following this, the conference was opened with a lecture by J. Bégueret
on the occurrence of prions in yeast and filamentous fungi. The talk concentrated
on Podospora anserina and evidence was presented that a protein
encoded by the het-s gene is a prion.

Chris
Caten, Sarah Rawlings, Sarah Perfect, Jon Green and Jim Croft basking in
French sunshine.
The
following day began with a plenary session on gene silencing with lectures
from J. Rossignol on DNA methylation and gene silencing in Ascobolus,
and G. Macino on quelling in Neurospora crassa. From this session
it was apparent that gene silencing occurs in many fungal species. The
theme of gene expression and its regulation continued through the following
workshop chaired by M. Caddick and H. Haas. C. Ribard introduced us to
the regulation of the adenine deaminase (nadA) gene of Aspergillus
nidulans which involves both specific and general activators. In contrast
to many genes, it was observed that the GATA factor AreA had a negative
rather than a positive effect on the expression of nadA, and that
this might reflect the role of nadA in both purine catabolism and
salvage pathways. A general conclusion was that the complexity of regulatory
mechanisms governing many fungal genes, especially those encoding metabolic
enzymes, allows co-ordinate expression and efficient use of limited nutrient
resources.
Until
fairly recently, it would have been unusual to see a whole workshop session
purely devoted to genomics and bioinformatics. It is, nonetheless, difficult
nowadays to escape these disciplines which impinge on so many areas of
fungal genetics. R. Dean introduced the International Rice Blast Genome
Project, reporting that they had completed the fingerprint and end-sequence
analyses of a 25-fold genome coverage BAC library. High density cDNA macroarrays
are being used to identify genes expressed during appressorium formation
and infection of rice. Other genomics projects described in this session
included the MIPS Neurospora crassa database (G. Mannhaupt), the
Fusarium
venenatum EST project (M. Rey), characterisation of genes expressed
in Blumeria graminis f. sp. hordei (S. Thomas), gene profiling
in cutinase-expressing Saccharomyces cerevisiae (C. Sagt), durable
resources for discovery and development of new gene products from Trichoderma
reesei and Aspergillus niger (N. Dunn-Coleman), and a rapid
and general method for efficient gene replacement in filamentous fungi
(C. D’Enfert).

Simon
Cutler climbing the Pyla Dune - "It's tough being a fungal geneticist!"
The
“evening’s entertainment” was firstly provided by Claudio Scazzocchio who
gave an animated presentation of his work on nucleosome positioning in
fungal promoters. John Hamer of Paradigm Genetics followed by unveiling
his latest tool for genomics, that of “Scazzocchiomics”, and then described
transposon
arrayed
gene
knock-out
(TagKO) technology and nutritional profiling. It is believed that these
techniques will enable rapid assaying of fungal phenotypes.
The
third day was opened by Pierre de Wit with an impressive plenary lecture
outlining his life’s work on the structure and function of virulence and
avirulence genes of Cladosporium fulvum and Cf resistance
genes of tomato. The data suggest the presence of a versatile surveillance
system for recognition of foreign proteins in various wild Lycopersicon
species. This was followed by a workshop on fungal pathogenicity at which
our own Sarah Perfect was invited to participate. She too talked about
her life’s work (though a little shorter than Pierre de Wit’s) describing
the distribution and characterisation of the biotrophy-related gene CIH1
within the genus Colletotrichum. The congress provided the perfect
opportunity to present a talk at such a prestigious international meeting.
It also provided Sarah Rawlings of Birmingham (together with Bleddyn Hughes,
Richard O’Connell and Jon Green) a chance to display a poster entitled
“The molecular and cellular basis of spore adhesion in Colletotricum
lindemuthianum”. Colletotrichum was again considered by A. Pellier
discussing a transcriptional activator, CLTA1, involved in pathogenicity.
The role of cell wall degrading enzymes from Claviceps purpurea during
infection of rye was presented by P. Heidrich. In a second session (must
be an important area eh?) on fungal pathogenicity, Pietro Spanu described
the role of hydrophobins in dispersal of Cladosporium fulvum using
gene-knockout mutants in a talk entitled “Fungal raincoats as dispersal
aids”.
Mobile
elements, cellular degeneration and senescence provided the material for
a further workshop, and included presentations by Frank Kempken on transposon-directed
mutagenesis in filamentous fungi, Anton Sonnenberg on a LTR-retrotransposon
in Agaricus bisporus, and Jack Kennell on telomere-like mitochondrial
retroplasmids of Fusarium oxysporum. The University of Birmingham
were represented in this section with a poster by Jennifer Rawson, Simon
Cutler and Chris Caten entitled “Transposable elements in the phytopathogenic
fungus Stagonospora nodorum”. In the concurrent session on cell
biology, Tim Bourett presented his elegant images obtained using GFP and
its spectral variants to study Magnaporthe grisea. An evening of
culinary delight lay ahead for delegates as the Mayor of Arcachon invited
us to enjoy the local produce of oysters (greeted with a mixed reception).
On
the final day, participants were educated by Marguerite Picard in the unexpected
facets of sexual development in fungi, before Cees van den Hondel closed
the congress and summed up. Delegates were treated to a wine tasting and
farewell dinner in the Saint Estephe wine area, and continued dancing and
drinking late(ish) into the night and during the 2 hour (!) coach journey
home.
We
would like to thank the BSPP for their generous support enabling us to
participate in this conference.
Simon
Cutler, Sarah Perfect and Sarah Rawlings
The
University of Birmingham
BSPP Presidential Meeting
"Biotic interactions in plant-pathogen associations"
Oxford : 19-22 December
1999
This meeting was attending
by about 120 delegates with a mix of well-established scientists and young
enthusiastic post-graduate students. The weather at that time was very
wintry and much snow had fallen in Oxfordshire making Oxford look
pretty.
Professor Mike Jeger gave
the presidential address, setting the scene by giving a broad overview
of the theory of plant disease epidemics. During the next three days, there
was a tremendous accumulation of knowledge in biotic interactions - all
with the aim of better understanding the pathogen and providing ways to
control the disease.
The Garrett Memorial Lecture,
given by Professor Thomas Pirone (University of Kentucky, USA)
provided a clear and fascinating talk on aphid transmission of potyviruses
that focused on the complexities of the transmission
process. A poster session then follow where I had the opportunity to present
my work on dsRNA virus with effects on growth and virulence in Verticillium
fungicola infecting cultivated mushroom. The meeting also included
the BSPP-sponsored P.H. Gregory paper competition and the poster competition
sponsored by the Association of Applied Biologists Virology Group. The
winning paper presentation was titled ‘The effects of environmental
factors on light leaf spot epidemics on winter oilseed rape in the UK’
by Tijs Gilles; IACR-Rothamsted UK. The winning poster presentation
was titled ‘Sequence analysis of Furoviruses of cereals from China and
Europe’ by Aipo Diao and M.J. Adams ; IACR-Rothamsted UK.
The atmosphere of the conference
dinner at the hall of Hertford College was very warm and friendly. The
meeting was well organised, discussions were stimulating and provided a
great opportunity to meet others working in this area. I would especially
like to thank Dr Mark Hocart, Mrs Morag Hay, Dr Nicola Spence, Professor
Chris Gilligan and everyone else responsible for the organisation of such
a successful meeting. I would also like to acknowledge the generous award
from BSPP Travel Fund which allowed me to attend this enjoyable, friendly
and stimulating meeting.
Angsana Akarapisan
Chiang Mai University,
Thailand.
First International Meeting
on Phytophtoras in Forest and Wildland Ecosystems
Grants Pass, Oregon : 30
Aug - 3 Sept 1999
On the flight from Seattle
to Medford the snow capped peaks of Mt. St. Helens and Mt. Hood provided
a backdrop to the vast acreage of coniferous forest in the Pacific north
west of the USA. The widespread death of the important Port Orford
Cedars in these forests as a result of Phytophthora lateralis infection
serves as a stark reminder of the dangers of introductions of alien Phytophthora
species and was a key theme running through the 5-day meeting.
The conference was organised
by the IUFRO (International Union of Forestry Research Organizations) working
party on Phytophthora diseases. The 45 or so delegates, principally
from the USA, Australia and Europe met in the small town of Grants Pass
in Southern Oregon which provided an excellent base for visits to local
forests with Phytophthora problems as well as an exciting evening’s
jet boat ride down the Rogue River.
After an overview of the
main problems in Europe, Australasia and the Americas by Clive Brasier,
Ken Old and Everett Hansen there followed sessions on many aspects of Phytophthora
biology and management. The first on the ecology, epidemiology and
impacts of Phytophthora highlighted the problems caused by P.
cinnamomi in Portuguese cork oak and Australian native vegetation,
P.
quercina on oaks across much of Europe and a hybrid species responsible
for death of hundreds of thousands of alder trees in NW Europe. In
the session on biology and genetics, contrasting cases were presented which
illustrated the range of genetic plasticity encountered in Phytophthora.
In Oregon virtually no genetic variation amongst isolates of P. lateralis
from Port Orford Cedar suggested a relatively recent importation. In the
case of the hybrid alder Phytophthora found in Europe, tremendous
genetic, morphological and cytological diversity was indicative of a recent
interspecific hybridisation event. Alas we do not know the origin
of either the P. lateralis outbreak or sufficient detail of the
hybrid’s parents but both demonstrate the threat Phytophthora can
pose and the need for rigorous testing of health status checks in international
plant trade. I added to this session with a presentation (collaborative
work with colleagues in Munich) on the genetic diversity of P. quercina,
another pathogen increasing in incidence and severity but of unknown origin.
In other sessions on pathogenicity
testing and disease management we learnt of the work to both control and
limit the spread of P. cinnamomi in Alcoa’s bauxite mining operations
in W. Australia where world heritage sites are threatened. Along
with a presentation on risk analysis and resistance breeding to minimise
the P. lateralis threat in Port Orford Cedar it was possible to
gauge the practical measures that could be taken to limit introductions
once they had occurred.
In the final session we heard
of changes in disease patterns that could occur if climate change should
continue as predicted. We also returned to some common themes
in Phytophthora research; the difficulties in isolation, identification
and detection and the applicability of in vitro c.f. whole plant
bait tests as a measure of pathogenicity. In this session I
presented my Phytophthora identification module based on rDNA internal
transcribed spacer (ITS) profiling and highlighted the forthcoming web
site designed to aid Phytophthora identification in this manner.
The IUFRO Working Party 7.02.09
business meeting chaired by Ken Old summarised the key issues raised during
the meeting; the need to assess the potential threats of introductions
of ‘wild’ and geographically restricted Phytophthoras to native vegetation;
the impact of global climate change and the threats of hybrid formation
caused by the failure of plant health legislation to prevent import and
export of plant material infected with Phytophthora.
I would like to thank the
British Society for Plant Pathology and the Scottish Society for Crop Research
for supporting this opportunity to present my work to an international
audience as well as the Scottish Executive for Rural Affairs Department
and the British Council/DAAD for supporting the Phytophthora research
undertaken at SCRI. Lastly a big thank you to Professor Everett Hansen
and his colleagues for organising a meeting that was both scientifically
stimulating and great fun.
David Cooke
Scottish Crop Research
Institute
Cambridge Mycology and
Plant Pathology Club - 50th Anniversary Meeting
To celebrate the first 50
years of the Cambridge Club a special afternoon meeting was organised on
30 June 2000 in the Department of Plant Sciences, Cambridge. We gratefully
acknowledge financial support from BSPP for this meeting. The founding
organisations provided reviews of their activities and short papers were
offered by members. The President, Henry Tribe, opened the meeting with
a historical review pointing out that an increase in the number of organisations
with an interest in plant pathology and their dispersal around Cambridge
had prompted W Dillon-Weston (NAAS) and Professor Noel Robertson (Botany
School) to establish the Club. The first meeting on 6 November
1950 featured a talk by W A R Dillon-Weston on ‘Diseases in
East Anglia’. We were pleased to see representatives from the very
first meeting, namely June Baker (nee Ives) and Jean Welbank (nee Drayner)
at this reunion.
Professor Chris Gilligan
showed the linkages between current work in the Department of Plant Sciences
and that of Denis Garrett, John Rishbeth, David Ingram and Peter
Lowings. The challenge of scaling up from the individual to the field
was illustrated using Rhizoctonia solani, take-all and rhizomania.
Valerie Silvey of NIAB showed how interest in diseases has increased over
the last 40 years – powdery mildew on Proctor spring barley and yellow
rust on Rothwell Perdix wheat have stimulated much cereal pathology!
Wheat yields in NIAB trials increased from 5.0 t/ha in 1972 to 7.8 t/ha
in 1992 and this was accompanied by major changes in husbandry and fungicide
use. Avice Hall of the University of Hertfordshire provided links
dating to 1952 when Peter Day was based at Bayfordbury, near Hertford.
Teaching and research activities on a diversity of topics were outlined
and practical links are to the fore with a new CD on ‘Environmental Management
for Agriculture’ selling well. Professor John Mansfield offered his
congratulations on reaching the 50th Anniversary and indicated how
vital it was not to lose touch with the diversity of plant pathology activities.
David Yarham provided personal
reminiscences of advisory work. Agricultural changes since the 1950s
included increased mechanisation, increased use of nitrogen and herbicides,
derationing of animal feed, continuous cereal production and development
of improved varieties, most notably Capelle Desprez. Take-all had been
a special interest, it being one of the few diseases one could do something
about in the pre-fungicide era. There were early pointers of future problems
with fungicide resistance when resistance to mercury seed treatment occurred
in oat leaf spot pathogen. Early foliar disease control involved
ethirimol seed treatment and zineb sprays for powdery mildew in spring
barley. Large scale experiments in Norfolk at that time involved
crops in an area of 5 square miles. Subsequently environmental concerns
about pesticides were addressed through the Boxworth project and its successors.
Advisory activities have changed along with agriculture, but the multi-disciplinary
approach remains as important as ever.
The pioneering work of Peter
Lowings in dealing with diseases in ships cargoes was acknowledged as Anna
Snowdon provided tales of the perils of being a fruit or vegetable on the
high seas. Investigations of sclerotinia rots in carrots and ripening
of bananas provided excellent case studies of detective work. John
Gibbs acknowledged the influence of Denis Garrett in stimulating his interest
in pathology. Work has continuing to extend the work of John Rishbeth
with Phlebiopsis (formerly Peniophora) gigantea
for bio-control of butt rot (Heterbasidion annosum) to mechanised
harvesters. There is also the prospect that control will be developed for
spruce stumps in future. Oak wilt provided a second case study and it may
be possible to exploit weaknesses in its saprophytic phase to achieve some
measure of biological control.
The meeting was attended
by 40 members, most of whom were captured on film after celebrating with
a round of champagne kindly provided by the British Mycological Society.
This was followed by a dinner at Downing College, Cambridge attended by
20 members.
On Saturday, 1 July, an
enthusiastic group were treated to a tour of Monsanto plc (previously Plant
Breeding International) guided by Richard Summers, Head of Wheat Breeding.
An enjoyable tour of field plots revealed a healthy spectrum of diseases
with something to interest everyone - be it root, stem, leaf or ear.
Meetings will be organised
in the autumn as we enter year 51. Contact the secretary, Peter Gladders
for further information (01954 268230; email peter.gladders@adas.co.uk)
Agricultural Microbes
Genome conference
San Diego, USA : 13-14 January
2000
The BSPP helped fund my visit
to the inaugural Agricultural Microbes Genome conference, held in San Diego,
following the regular Plant and Animal Genome (PAG) conference. We
felt it was important that our research group was represented at this meeting
and in fact my colleague Paul Birch and I were the only two UK delegates
working on plant pathology. We presented posters on current work
at SCRI entitled “Investigating the pathogenicity of Erwinia carotovora
subspecies
by genome mapping using BAC libraries” and “Construction of a bacterial
artificial chromosome library of the late blight pathogen
Phytophthora
infestans”.
Although the conference was
small (with only 160 present) it will be remembered for an announcement
that marks a new era in plant pathology: the first completed genome sequence
of a plant pathogen. The conference was also valuable for illustrating
the power of genomics approaches to allow new understanding of microbes
and also some practical approaches to genomics studies. I shall refer in
particular to three presentations.
Andrew Simpson (Ludwig Institute,
Brazil) stole the show with the announcement that a Brazilian consortium
has completed sequencing the genome of the bacterium Xylella fastidiosa.
This was a remarkable story for many reasons: the manner in which the
Brazilian scientific community pulled together to achieve a world first;
the way they overcame limited resources and expertise; the stimulus the
project has provided for Brazilian science and of course the implications
for plant pathology.
This bacterium is the cause
of a number of plant diseases. Only in 1987 was it discovered to
be the cause of citrus variegated chlorosis. São Paoulo state
is the world’s biggest citrus producer and now 83% of its trees are infected,
which is having a major effect on the citrus crop. However, very little
of the basis of the pathology of this organism was understood other than
that it clogged xylem vessels in the host. Prior to the project only
rRNA genes had been sequenced and there were no genetic maps or cosmid
libraries available. Now, however, with the complete genome sequence
there is a huge amount that is known or surmised about the physiology and
pathology of X. fastidiosa. No other approach could have yielded
so much information in so little time (around 2 years). Interesting
traits of X. fastidiosa include that it appears to use only monosaccharides
as a source of carbon; it has few transport proteins and it has very different
polysaccharide biosynthesis to E. coli. It possesses a diverse
arsenal of weapons with which to attack its hosts: haemolysins, pectinases,
adhesins, toxins and a xanthan gum operon (similar to that in Xanthomonas).
The synthetic pathway and structure of this gum have been predicted.
Surprisingly, X. fastidiosa appears to lack the Type III secretory
system that seems to be so common in pathogens. Functional genomics
studies are ongoing and the Brazilians have already begun a sequencing
project for Xanthamonas citri.
Mary E. Lidstrom of the University
of Washington gave an interesting talk on genomics efforts with Methylobacterium
extorquens. This plant epiphyte uses methanol released from plants
as its soul carbon source. Its peculiar C1 metabolism is of interest
in biosynthetic applications. One of the main points to come out
of this talk was that genome sequencing projects can be much cheaper than
people might imagine. To complete a genome sequence requires sequencing
of a library of random subclones estimated to cover the genome several
times, followed by directed gap closure. However, sequencing a library
of subclones equivalent to only one-fold genome coverage is far less laborious
and less expensive but should still give around 60 % of the whole genome
sequence. Furthermore, some sequence information should be obtained
from more than 90 % of genes by this strategy. This is sufficient
to allow the identification of putative new genes and operons. Many
interesting new genes involved in C1 metabolism and other functions have
been identified in this project which was funded by a relatively small
“single investigator” grant rather than the multi-million pound collaborative
grants often required for sequencing. Also, in this relatively small
scale project the investigators had sequences returned to them in small
batches and so they were able to perform sequence database searches and
annotations and deposit their own sequences in the public databases as
they went along. This is in contrast to other projects where there
is sometimes a long delay between a sequence being obtained, analysed,
annotated and released to the community often resulting in a conflict of
interest between public funding agencies who may wish for quick release
and the investigators who may not wish to release until they have got what
they can from the sequences. From their initial sequencing effort
this group was able to discover new sets of genes involved in methylotrophy
and in polyhydroxybutyrate synthesis.
Genomics in plant pathology
is in its infancy but progress in other areas gives us a view of the types
of studies that can be performed and the insights that they can provide.
Incredibly, in some fields of microbiology we are now in the post-genome
sequencing era. In a talk by Martin Rosenberg entitled “Genomic approaches
to antimicrobial discovery” we learned that his company SmithKline Beecham
now have all the microbial genome sequences that they require at present.
Analysis of these sequences has already yielded a number of potential new
targets for antibiotic activity. This represents remarkable progress given
that in the last 25 years no new antibiotic mechanism has reached the market.
The most important use of whole genome sequences in this area is to look
at gene expression. For in vitro studies DNA can be spotted
onto chips with each spot corresponding to a gene or putative gene (open
reading frame or ORF). RNA can be screened against these chips to
examine expression of every gene in the genome under particular conditions.
Unfortunately at present this method is not sensitive enough to look at
gene expression in the context of host-pathogen interactions and the more
laborious method of fluorescent RT-PCR is required. This is only
relatively laborious however: high throughput approaches mean that 2 postdocs
in 2 weeks were able to monitor expression of 1700 ORFs in duplicate.
Another strategy SKB is actively pursuing is allelic replacement mutagenesis
which can be used to knock out genes to determine those essential for growth,
thus providing new candidate genes for antibiotic action.
As antibiotic resistance
continues to spread, Dr Rosenberg presented us with a frightening scenario
in which the later part of the 20th century and the early part of the 21st
might in future be remembered as a “blip” in which mankind had antibiotic
protection from infectious disease. We are in a race to find new
targets and mechanisms for antimicrobial action and Dr Rosenberg said that,
other than a genomics approach “I don’t know another way to do it. If we
don’t do it this way we are in pretty deep shit. Maybe we won’t have to
worry about Alzheimer’s”!
Attending this conference
made a number of things clear to me. It showed just how powerful
genomic approaches can be in providing new understanding of microbes (that
could not be obtained by other methods) and how little plant pathogen genomics
is actually ongoing. There seems to be a feeling that genome sequencing
projects are too expensive to be undertaken and maybe America is where
it will all happen. These were shown to be misconceptions by the
talks by Andrew Simpson and Mary Lidstrom and also in the comments of Noel
Keen. Dr Keen berated the American funding agencies for failing to
support plant pathogen genomics and said that this meant that all of plant
pathology was losing out as a result. British plant pathology must
now make best use of its wits and resources to meet the challenges and
seize the opportunities that the new age of genomics presents. I
wish to thank the BSPP for helping me to attend this remarkable conference.
Kenneth Bell
Scottish Crop Research
Institute, Dundee
10th International Rapeseed
Congress
Canberra : 26-29 September
1999
The 10th International Rapeseed
Congress was held at the International Conference Centre, Canberra, Australia.
The conference centre was part of a complex of hotels with nearby restaurants
and a casino situated in central Canberra. The new and rather imposing
Australian parliament building was also just down the road (a dubious term
to use in an Australian context). The week also marked the beginning of
the Canberra floriade enabling delegates to wander as a cloud between some
long or particularly harrowing conference sessions. The setting provided
a more than satisfactory experience given Canberra’s undeserved reputation.
The conference was attended
by about 700 delegates and had representation from most of the brassica
oilseed producing countries. It is relatively unusual for conferences these
days to be organised with a commodity as the main subject area. However
with such a wide variety of arable and horticultural brassicas this is
probably one of the few crop commodities outside cereals where this approach
can be adopted successfully. The major scientific themes of the conference
were plant breeding and biotechnology, chemistry and nutrition, crop production
within farming systems, constraints on production notably crop protection.
These themes were reflected in the keynote topics in the opening sessions.
Professor Moloney described use of crops of rapeseed as “factories”, for
the production of other compounds, in one keynote address. Although not
a new area certainly an increasingly important topic area for farming and
growing in the “new age precision era”. Although the technology seemed
well developed it occurred to me that there were certainly other easier
and more productive crops that could be and are currently being used for
this purpose. The dependence of the economics of rapeseed production on
the production of other oilseed crops especially, rather puzzlingly, on
palm oil underlined the need for other uses for the crop apart from as
a conventional food source.
The crop protection sessions
of the conference did not begin until the second day of the conference.
Despite this there were a large number of interesting presentations and
a considerable quantity and quality of posters to view. I found it
particularly interesting to learn that brassicas were non-hosts for vesicular
arbuscular mycorrhizal fungi. One series of oral presentations centred
on controlling diseases of rapeseed crops. There was an update on
the effect of glucosinolate biosynthesis on disease interactions which
featured in the previous congress in Cambridge in 1995. New results
were presented on the types and induction of biosynthetic pathways produced
when Brassica napus was infected with Sclerotinia sclerotorium.
Clubroot
(Plasmodiophora brassicae) infection on roots was shown to be linked
to the presence of indolyglucosinolates as a major component of their glucosinolate
profile.
The conference sessions
on the epidemiology of diseases of oilseed brassicas were of most relevance
to me. A review of the epidemiology, forecasting and management of
winter oilseed rape diseases provided a good blend of how newer techniques
could be used to control a range of diseases. The presentations on
the pathotypes of Albugo candida (white blister) which infect crucifers
were of particular interest given that disease is a major problem on vegetable
crucifers and has recently become a problem on oilseed rape grown in Scotland.
The poster session contained further information on the Scottish experience
with white blister. There were also interesting posters on modeling
life cycle stages of Pyrenopeziza brassicae (light leaf spot) and
Leptosphaeria
maculans (stem canker). Another topic area covered in this poster
session was the trapping of airborne inoculum and how this information
might be used in controlling Leptosphaeria. The use of new techniques
which are becoming more cost effective, rapid and user friendly for detecting
air-borne inoculum will see further impact in control of many of these
diseases. However the trapping systems that have been used to obtain samples
have often lagged behind the techniques used to analyse samples. Many of
the sampling problems in the air or in the crop have not been addressed
adequately.
The final day of the conference
had one of nine sessions devoted to host-pathogen interactions. The oral
presentations were of a good standard with new information on resistance
genes in Brassica napus to Leptosphaeria maculans.
Information on the mechanisms of resistance in mustard to Alternaria
brassicae, through the detoxification of the phytotoxin destruxin B,
was presented. The posters remained in position throughout the conference,
which is a definite benefit to the delegate. A good balance was maintained
between poster numbers and the presentation area, an aspect which is sometimes
overlooked in major international congresses. There were some interesting
poster presentations within the associated session on the development of
new biocontrol products for Sclerotinia sclerotiorium in oilseed
rape. Although biocontrol remains a very interesting topic area too often
it has been presented in terms of one disease on a crop type. However most
crops are affected by more than one disease which would make the practical
usage of biocontrol agents commercially more difficult. Chemical
control featured heavily in both the oral and poster sessions, which emphasised
the lack of impact of new technologies for controlling disease in arable
crucifer production. This is a potentially important point as the
increased costs involved in producing crops using new techniques may make
it impossible for areas where these techniques are being promoted to compete
with other areas where chemicals are the major crop protection input in
a free market.
A visit to the new parliament
building where one could sit in on some of the parliamentary sessions was
also deemed a necessity during breaks in the conference. At close
quarters one can appreciate its size even though its foyer looked like
some neo classical temple. I felt it appropriate to visit the senate.
Coincidentally I attended the conference dinner of the 12th Biennial Conference
of the Australasian Plant Pathological Society which was running in Canberra
at the same time. I was therefore able to enjoy both conferences
at the same time as they were being held approximately half a mile apart.
The 10th International Rapeseed Congress was a very enjoyable conference
with a large amount of new information presented. Canberra also provided
a very interesting backdrop to the congress with its many new restaurants.
Most of these were situated in the suburbs so it was not always easy for
delegates to meet up in the evening after the end of the sessions.
Some parts of the centre of the Canberra went very quiet in the evening
restricting the delegate in search of some types of entertainments. However
generally all aspects of the congress were a good success and the 11th
congress will be held in Europe in 2003.
R. Kennedy
Horticulture Research
International
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