Evidence for a Common Toolbox Based on Necrotrophy in a Fungal Lineage Spanning Necrotrophs, Biotrophs, Endophytes, Host Generalists and Specialists

The Sclerotiniaceae (Ascomycotina, Leotiomycetes) is a relatively recently evolved lineage of necrotrophic host generalists, and necrotrophic or biotrophic host specialists, some latent or symptomless. We hypothesized that they inherited a basic toolbox of genes for plant symbiosis from their common ancestor. Maintenance and evolutionary diversification of symbiosis could require selection on toolbox genes or on timing and magnitude of gene expression. The genes studied were chosen because their products have been previously investigated as pathogenicity factors in the Sclerotiniaceae. They encode proteins associated with cell wall degradation: acid protease 1 (acp1), aspartyl protease (asps), and polygalacturonases (pg1, pg3, pg5, pg6), and the oxalic acid (OA) pathway: a zinc finger transcription factor (pac1), and oxaloacetate acetylhydrolase (oah), catalyst in OA production, essential for full symptom production in Sclerotinia sclerotiorum. Site-specific likelihood analyses provided evidence for purifying selection in all 8 pathogenicity-related genes. Consistent with an evolutionary arms race model, positive selection was detected in 5 of 8 genes. Only generalists produced large, proliferating disease lesions on excised Arabidopsis thaliana leaves and oxalic acid by 72 hours in vitro. In planta expression of oah was 10–300 times greater among the necrotrophic host generalists than necrotrophic and biotrophic host specialists; pac1 was not differentially expressed. Ability to amplify 6/8 pathogenicity related genes and produce oxalic acid in all genera are consistent with the common toolbox hypothesis for this gene sample. That our data did not distinguish biotrophs from necrotrophs is consistent with 1) a common toolbox based on necrotrophy and 2) the most conservative interpretation of the 3-locus housekeeping gene phylogeny – a baseline of necrotrophy from which forms of biotrophy emerged at least twice. Early oah overexpression likely expands the host range of necrotrophic generalists in the Sclerotiniaceae, while specialists and biotrophs deploy oah, or other as-yet-unknown toolbox genes, differently

Report of a Working Group on Avena: Sixth meeting, jointly held with the final meeting of project AGRI GEN RES 061 on “Avena Genetic Resources for Quality in Human Consumption” (AVEQ), 19-22 October 2010, Bucharest, Romania

The sixth meeting of the ECPGR Working Group on Avena was held in Bucharest, Romania, on 21-22 October 2010, back-to-back with the final meeting of the AGRI GENRES project AVEQ on “Avena Genetic Resources for Quality in Human Consumption” (19-21 October). The first part of the publication reports the results of field experiments and analyses carried out in the framework of the AVEQ project, covering yield and technical quality, Fusarium-related issues, nutritional quality of oats and cold tolerance in oat genetic resources.The second part, dedicated to the activities of the ECPGR Working Group on Avena, focuses on wild species (collecting in Cyprus, Sicily and Spain in the framework of the AEGRO project; domestication, multiplication and regeneration issues) and on sharing of responsibilities, particularly for the implementation of “A European Genebank Integrated System” (AEGIS). Significant progress had been made in the ECPGR Avena Database, which can now integrate in situ data from the AEGRO project as well as evaluation data from the AVEQ project. The database can be used to define the Most Appropriate Accessions for the AEGIS European Collection. The material selected for the AVEQ project could immediately be suggested to become European accessions in the AEGIS system.Areas of interest for future project proposals were also discussed (wild species, base-broadening of A. sativa, domestication of the wild species, genotyping, etc.)

Variability of tocopherols, tocotrienols and avenanthramides contents in European oat germplasm

A broad spectrum of European oat genetic resources representing crop wild relatives, landraces, traditional, obsolete and modern cultivars, was observed in a multi-location field study all over Europe. Here analyses results of 173 accessions for tocopherols and tocotrienols, and of 137 accessions for avenanthramides from groat samples are reported. Genotype, environment and interaction effects, as observed on a set of standard cultivars, were highly significant for most of the targeted traits. Environment effects were often dominant. Higher contents of these compounds than previously reported in oat have been frequently found. High values of alpha-tocotrienol and avenanthramides were detected in grains of Avena strigosa. Also few cultivars of A. s ativa reached more than 100 mg kg(-1) alpha-tocotrienol. Contents of , gamma- and delta-tocols were low; the latter often close to the detection limits. Presence of avenanthramides in Avena species other than A. s ativa is shown for the first time