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The Oomycete Molecular Genetics Research Collaboration Network meeting was held at the De Wageningse Berg, Wageningen, The Netherlands. This traditionally American meeting had a distinctly European spirit this year due to the atypical location and inclusion of the Bevrijdings festival (celebration of liberation and freedom of The Netherlands by allied forces on May the 5th 1945) into the program. The location was not the only exception from the norm, as the name suggests, the network now wishes to encourage participation from scientists working with all Oomycete pathogens, not solely Phytophthora species as it has done in the past. Pieter van Wests group (University of Aberdeen) were responsible for interesting new additions such as the mycoparasite of P. infestans, Pythium oligandrum and the fresh water fish pathogen, Saprolegnia parasitica. The keynote speaker, Matthias Hahn, crossed kingdoms by giving an interesting lecture on nutrient uptake, metabolism and protein transfer by haustoria of rust fungi, Uromyces fabae and U. striatus in host Medicago tranculata.
I was fortunate to be given the opportunity to present our recent work characterising a plant cysteine protease, which was originally identified through SSH using P. infestans challenged potato leaf tissue. P. infestans has recently been shown to secrete protease inhibitors that almost certainly target defence-related proteases (Tian et al. 2004; 2005). These include cysteine protease inhibitors (EPICs) (Joe Win’s Poster) that are believed to function in the plant apoplast. Both fluorescent tagging with mRFP and protease activity profiling of apoplastic fluids revealed that Cathepsin B has an apoplastic location. This suggests that Cathepsin B is active in the appropriate location to be targeted by EPICs. It was interesting to discover that the fish pathogen, S. parasitica, like P. infestans, produces Kazal-like protease inhibitors as described by Emma Roberson. I hope that presenting our data on the role of Cathepsin B during plant defence responses was informative for the pathogen-focused attendees of the meeting.
The buzz word at this meeting seemed to be “RXLR”, an amino acid motif that is commonly associated with oomycete secreted effector proteins and many groups presented their bioinformatics data identifying them and / or molecular work characterising the proteins that contain them. Guido van den Ackerveken presented work on the identification of RXLRs and Kazal-like protease inhibitors, amongst other interesting protein classes, from downy mildew (Hyaloperonospora parasitica) ESTs using SignalP and Psort algorithms. Mary Coates described the discovery of 150 RXLRs in H. parasitica and current progress analysing the allelic variation. Brett Tyler described the identification of 170 genes encoding small secreted proteins from the P. sojae genome (all with either an RXLR or a dEER motif), and demonstrated that Avr1b requires one of its two RXLRs for function outside the soybean cells. Quantitative RT-PCR evidence for distinct expression profiles of the 50 RXLR-containing proteins from P. infestans, from pre-infection to necrotrophic stages of its life-cycle and the haustoria-associated location of RXLR-containing Avr3a, using mRFP tagging, was beautifully illustrated by Steve Whisson.
Brett Tyler announced that the preliminary assembly of the H. parasitica genome is now publicly available although there are no gene model predictions as yet (http://Phytophthora.vbi.vt.edu). Although most research presented relied on bioinformatics to varying degrees, posters and presentations describing work on the genome sequencing projects (Mike Zody), transcriptomics (Sandra Casimiro and Howard Judelson), proteomics (Catherine Bruce and Ilham Badreddine) and other genome-wide approaches to gene discovery (Alon Savidor) emphasized the vast amount of data being produced during this Omics era should be carefully analysed and annotated by both bioinformatians and molecular biologists. The main conclusion being that there is an ever increasing demand for even tighter collaboration and communication between the wet and dry biological sciences.
Thank you BSPP for funds towards this trip.
Dr Eleanor Gilroy, SCRI, Scotland
