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Joint 30th ESN Symposium and 5th Phylloxera Symposium, Vienna, Austria 19th – 23rd September 2010
The Joint 30th ESN Symposium and 5th Phylloxera Symposium hosted by the University of Natural Resources and Applied Life Sciences was attended by over 350 delegates from 39 countries, who gave 107 presentations, 159 posters and 4 workshops. There was a wide range of research interests represented which ranged from the entomopathogenic and entomophilic nematodes to functional genomics of plant parasitic nematodes and ecology, biodiversity and evolution.
Jonathan Hodgkin (University of Oxford, UK) presented the opening session on ‘host pathogen interaction in the nematode C. e legans ‘ . These interactions are providing insights into many of the C. elegans genes with previously unknown function, giving a greater understanding of innate immunity. This system may also be used to investigate human pathogens whose host interact ions would otherwise be difficult to study. Heribert Hirt (URGV Plant Genomics, France) presented the second opening session entitled ‘living with uninvited guests: molecular mechanisms of the interactions of Agrobacterium and Salmonella with plants’. Recently a salmonella-GFP construct has been shown to have the potential to infect plants with successful infection of roots in as little as 2 hours. Another interesting observation is that infected salad and vegetable crops present few or no symptoms and those which are not thoroughly cooked may account for 6-9% of Salmonella cases in the US.
Sofia Costa presented ‘the potential role of rhizobia-plant-nematode interactions in plant invasion’. Acacia longifolia was introduced to Portugal from Australia to stabilise sand dunes and has now become an invasive species. The enemy release hypothesis is thought to be responsible as the natural nematode parasite has been left behind in Western Australia. As the infection and nodul at ion me c ha ni sms shar e biochemical pathways Costa et al.
investigated the interactions between rhizobia and Meloidogyne it was discovered that galling was inversely related to nodulation and this was independent of nitrogen fixation efficiency. As such rhizobia are able to protect plants from nematode infection, possibly by mimicking a heavily infected plant, which would be unsuitable for further parasitism.
Danny Coyne presented an interesting paper on the ‘pesticide problem in Africa’. While the majority of the world has seen increases in yields, African yields have remained stagnant at ~ 1t/ ha often leading to food shortages.
Pesticides are often used in large quantities, for off label applications and continue to be used after they stop being effective. Danny argued that Africa is a huge developing market but it has specific problems; many of the growers are poorly educated and need to be taught basic agronomy. Pack size needs to be reduced to single field applications as large barrels of chemicals are prohibitively expensive and many growers do not understand how to dilute the chemical appropriately. One example given was of cocoa growers who achieved a 40% increase in yield with a 10-20% reduction in pesticide application after being taught the proper use of pesticides.
There were several social events organised at the conference. On the Monday evening delegates were invited to dinner with the mayor of Vienna, Michael Häupl at the Rathaus, Vienna city hall, a magnificent building in the Ringstrasse area of town. On the third day of the conference excursions were organised to either the Wachau valley or Lake Neusiedl, before meeting for dinner in a traditional Austrian wine tavern. And finally the conference dinner was held in the vaults of the Klosterneuburg monastery.
Sam Gorny Rothamsted Research The 10th International Symposium on Cytochrome P450 Biodiversity and Biotechnology, Woods Hole, Massachusetts, USA 3rd – 10th October 2010 So what is Cytochrome P450, and what has it got to do with plant pathology? Cytochrome P450 is a protein superfamily comprising enzymes with a characteristic structure of helices, sheets, coils and loops, a haeme core, and an absorbance spectrum peaking at 450nm (in the reduced state). They have a wide range of functions: some are involved in steroid biosynthesis, many others are involved in the synthesis or detoxification of secondary metabolites. One Cytochrome P450, CYP51, is involved in sterol synthesis, and is also the target site of the azole fungicides, and it was my work on the role of multiple copies of CYP51 in azole sensitivity in Rhynchosporium secalis that brought me to this meeting.
Fungicide resistance in other species is mainly due to point mutations or overexpression of existing genes, so it was very useful to meet others who study gene duplications and losses in related gene families, as well as to see work addressing structural and biochemical aspects of these enzymes.
The first session looked at the evolution of P450 gene families, with phylogenetic work showing the diversification of P450 into a plethora of genes, and structural and functional analyses showing which features vary between genes and which are conserved across the entire superfamily. The topic of the next session was plant P450s, many of which are involved in plant defence, with P450 -catalysed steps in the synthesis of plant secondary metabolites including camalexin, avenacin, glucosinolates and monoterpenes. A session on insect P450s discussed those involved in insecticide resistance and others that showed remarkable co-evolution and convergent evolution with host plants, either to detoxify the plant’s defensive compounds, or to go from utilising compounds made by the plant to synthesising them de novo.
We then had a free afternoon to explore the conference venue, the Marine Biological Laboratory and Woods Hole Oceanographic Institution. This included a chance to go onboard one of their research ships, the Atlantis, as well as going to the WHOI visitor centre, with a repl ica of the Alvin deep-sea submersible from which hydrothermal vents were discovered, and the MBL visitor centre, with displays about discoveries made there, most notably their role in the cloning of GFP.
The session on microbial and fungal P450s covered azole resistance in fungi, trypanosome CYP51s as possible drug targets, and P450s involved in TB infection. Further sessions included talks on bioengineering of P450s, with researchers trying to modify enzymes for increased activity or altered substrate ranges; mechanistic studies of interactions with substrates, P450 reductases and carrier proteins; and uses in bioremediation.
The meeting also included poster sessions, where I presented my poster. Other students and post-docs presented work on P450s involved in plant defence, the P450s from fungal genomes, and innumerable protein structures and absorption spectra. Finally, the conference dinner saw the conference organisers singing a specially-written P450 song !
Unfortunately we were asked not to post videos on the internet. I was also delighted, and very surprised, to be awarded one of the student poster prizes. Overall, this conference was a valuable opportunity to engage with the P450 community and put my work into a wider biochemical and evolutionary context, and I am grateful to the BSPP for the travel award that enabled me to attend.
Nichola Hawkins Rothamsted Research
