title: Transcriptional analysis of mating and pre-infection stages of the anther smut,Microbotryum lychnidis-dioicae.
abstract: Microbotryum lychnidis-dioicaeis an obligate biotrophic parasite of the wildflower speciesSilene latifolia. This dikaryotic fungus, commonly known as an anther smut, requires that haploid, yeast-like sporidia of opposite mating types fuse and differentiate into dikaryotic hyphae that penetrate host tissue as part of the fungal life cycle. Mating occurs under conditions of cool temperatures and limited nutrients. Further development requires host cues or chemical mimics, including a variety of lipids, e.g. phytols. To identify global changes in transcription associated with developmental shifts, RNA-Seq was conducted at severalin vitrostages of fungal propagation, i.e. haploid cells grown independently on rich and nutrient-limited media, mated cells on nutrient-limited media as well as a time course of such mated cells exposed to phytol. Comparison of haploid cells grown under rich and nutrient-limited conditions identified classes of genes probably associated with general nutrient availability, including components of the RNAi machinery. Some gene enrichment patterns comparing the nutrient-limited and mated transcriptomes suggested gene expression changes associated with the mating programme (e.g. homeodomain binding proteins, secreted proteins, proteins unique toM. lychnidis-dioicae¸ multicopper oxidases and RhoGEFs). Analysis for phytol treatment compared with mated cells alone allowed identification of genes likely to be involved in the dikaryotic switch (e.g. oligopeptide transporters). Gene categories of particular note in all three conditions included those in the major facilitator superfamily, proteins containing PFAM domains of the secretory lipase family as well as proteins predicted to be secreted, many of which have the hallmarks of fungal effectors with potential roles in pathogenicity.
authors.affiliation: Department of Biology, Program on Disease Evolution, University of Louisville, Louisville, KY 40292, USA.|Present address: DSO National Laboratories, Defence Medical and Environmental Research Institute, Singapore.
authors.forename: Su San
authors.initials: SS
authors.lastname: Toh
authors.affiliation: Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.|Present address: WuXi NextCODE, Cambridge, MA, USA.
authors.forename: Zehua
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Biology, Program on Disease Evolution, University of Louisville, Louisville, KY 40292, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Schultz
authors.affiliation: Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Cuomo
authors.affiliation: Department of Biology, Program on Disease Evolution, University of Louisville, Louisville, KY 40292, USA.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Perlin
keywords: Microbotryum violaceum; dimorphism; mating; transcriptome