Most fungal effectors are genus, species or race-specific, however a few are more broadly conserved (e.g. ECP6), and some are discontinuously distributed within the Fungi (Ave1 & AvrLm6). Single orthologs of Ave1 from Verticillium dahliae, a virulence effector that activates Ve1-mediated resistance in tomato, have been identified in unrelated fungi (Colletotrichum higginsianum, Cercospora beticola, Fusarium oxysporum f. sp. lycopersici). A subset of these activate Ve1-mediated resistance in tomato (de Jonge et al. 2012). Ave1 also shares similarity to an ortholog in the phytopathogenic bacterium Xanthomonas axonopodis pv. citri, as well as to a common family of plant natriuretic peptides and expansins, involved in plant homeostasis and plant cell wall modifications (de Jonge et al. 2012). We have identified highly expanded Ave1-like gene families (with conserved predicted cysteine patterns & 37-57% overall aa identity) in the biotrophic scab fungi, Venturia inaequalis (5 genomes) & V. pirina. The orthologs are closely associated with repeats in Venturia genomes, however only a few appear to be impacted by RIP. Like VdAve1, Venturia orthologs have a conserved intron in the 5’UTR, which causes problems for automated gene calling, especially those packages informed by transcriptome data. Several of the Venturia orthologs are up-regulated during leaf infection (RNAseq data), and some are also highly expressed during in vitro growth on cellophane (RNAseq and proteomic data, Cook et al. 2014). Synthetic peptides (36 & 39 amino acids) from two V. inaequalis Ave1 orthologs, based on conserved homeostasis-regulating domains of plant proteins, affected Arabidopsis thaliana protoplasts (swelling) and guard cells (collapse) of Tradescantia leaves in epidermal peels exposed to the peptides (0.1µM) in solution. We hypothesize that Venturia Ave1 proteins may play a role during biotrophic infection in disturbing plant homeostasis and promoting nutrient release from plant cells.
|Title of host publication||Book of Abstracts 28th Fungal Genetics Conference|
|Publication status||Published - 2015|
|Event||28th Fungal Genetics Conference, Pacific Grove, CA, USA - |
Duration: 17 Mar 2015 → 22 Mar 2015
|Conference||28th Fungal Genetics Conference, Pacific Grove, CA, USA|
|Period||17/03/15 → 22/03/15|