Verticillium transcription activator of adhesion Vta2 suppressesmicrosclerotia formation and is required for systemic infection ofplant roots

摘要

Six transcription regulatory genes of the Verticillium plant pathogen, which reprogrammednonadherent budding yeasts for adhesion, were isolated by a genetic screen to identify controlelements for early plant infection. Verticillium transcription activator of adhesion Vta2 is highly conserved in filamentousfungi but not present in yeasts. The Magnaporthe grisea ortholog conidiation regulator Con7controls the formation of appressoria which are absent in Verticillium species. Vta2 was analyzedby using genetics, cell biology, transcriptomics, secretome proteomics and plant pathogenicityassays. Nuclear Vta2 activates the expression of the adhesin-encoding yeast flocculin genes FLO1and FLO11. Vta2 is required for fungal growth of Verticillium where it is a positive regulatorof conidiation. Vta2 is mandatory for accurate timing and suppression of microsclerotia asresting structures. Vta2 controls expression of 270 transcripts, including 10 putative genes foradhesins and 57 for secreted proteins. Vta2 controls the level of 125 secreted proteins, includingputative adhesins or effector molecules and a secreted catalase-peroxidase. Vta2 is amajor regulator of fungal pathogenesis, and controls host-plant root infection and H2O2detoxification. Verticillium impaired in Vta2 is unable to colonize plants and induce disease symptoms.Vta2 represents an interesting target for controlling the growth and development of thesevascular pathogens.