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The APS Annual Meeting, Florida, USA 30th July – 3rd August 2016
Meeting of the American Phytopathological Society which this year was held at the Convention Centre in Tampa, Florida.
The venue (pictured below) was on the waterfront which provided a relaxing backdrop to the conference although the temperature was consistently around 34Â°C. The conference programme was extremely diverse consisting of a first day of field trips and workshops followed by three days of plenary, technical, special and ‘hot topic’ sessions as well as specialist group meetings. With over 1,500 delegates and almost 1,000 posters this was a big meeting with a lot of information to take in, so it was important to do some homework and find the sessions which provided the most personal interest.
Fortunately, APS provided a very useful app with the programme and abstracts which also included a personal agenda with reminders.
On the first day, I attended a workshop on amplicon sequencing run by Lance Cadle-Davidson who presented a wide range of applications for the technique.
As well as the more obvious metagenomics applications for analysing microbial communities etc. it has also been used to genotype crop accessions in marker assisted breeding programmes (in vine), candidate gene profiling (e.g. detecting recombinations / allelic variants), genotype by sequencing tag conversion and fungicide resistance screening. Amazingly in plant pathogen population studies, up to 400 primer pairs can be used per DNA sample for multi-locus genotypjng. Ampseq is therefore a powerful technique with multiple applications.
One of the major re- occurring themes throughout the meeting which I was particularly interested in was the ‘phytobiome’ where next generation sequencing techniques (primarily ampseq) is being used to understand the communities of microorganisms in the phyllosphere and rhizosphere and how they interact with plant pathogens and plants. The emphasis of this theme coincided with the launch of a new APS journal ‘Phytobiomes’.
In the plenary session ‘Science into Practice’ Linda Kinkel presented a talk on phytobiome ecology. Using metagenomic approaches she has begun to unravel the components of soils suppressive to plant pathogens – in this case, a suppressive soil resulting from 30 years of monoculturing potatoes!
Interestingly this soil contained a high level of streptomyces all competing with each other through the release of antibiotics which in turn provided the disease suppression. In contrast, a disease conducive soil had fewer, less competitive species. This and further evidence supported the theory that plant monocultures can result in high niche overlap, co-evolutionary competition and higher levels of antagonism. It will be interesting to see how this can be adapted to grower practice in the future.
In the metagenomics and the phytobiome technical session, Pedrozo et al. explored the soybean seed core mycobiome using ITS amplicon sequencing and identified key fungal species that occurred across seed lots from multiple locations and plant genotypes. Inderbitzin et al. compared prokaryote communities in untreated soils and soils amended with treatments such as broccoli residue and crab meal for the control of Verticillium dahliae and found that although soil type, time of sampling, and amendment affected microbial community composition, a sub-set of taxa was more abundant in disease suppressive treatments than in controls.
Known biological control genera were more abundant in the amendment treatments; however, these were still at relatively low levels. Lastly Poudel et al. analysed the impacts of different tomato rootstocks on the rhizobiome and compared the microbial communities in both roots and rhizosphere. Although there was no clear affect of rootstock across three farm sites, the highest yielding rootstock tended to support a more diverse community. The rhizosphere also had a much higher microbial diversity compared to the roots across all samples. This session therefore gave a flavour of the diverse areas where the phytobiome is being explored but there is obviously some way to go before this information can be put to practical use.
I would like to thank the BSPP for providing funding to allow me to attend the meeting and give a talk on talk on Fusarium pathogenicity in onion and present a poster on Sclerotinia species diversity in the UK and Norway. Both were well received.
John Clarkson University of Warwick