Phytophthora infestans LC/MS/MS

ABSTRACT: The oomycete potato blight pathogen Phytophthora infestans secretes a diverse set of proteins to manipulate host plant immunity. However, there is limited knowledge about the role(s) of majority of these secreted proteins. Here we subjected extracellular proteins from in vitro cultured hyphae to LC/MS/MS to investigate the cargo of protein secretion pathways in P. infestans, in particular the conventional secretory pathway. Like the apoplastic effector EPIC1 (a cysteine protease inhibitor), we show that secretion of cell wall degrading enzymes and pathogen associated molecular pattern (PAMP)-like proteins is inhibited by brefeldin A (BFA) in vitro and in planta, demonstrating that these proteins are secreted by the conventional, Golgi-mediated pathway. For comparison, an RXLR (Arg-any amino acid-Leu-Arg) effector, Pi22926, was shown to be unconventionally secreted at haustoria, pathogen structures that penetrate host plant cells, and delivered into infected cells to suppress host defences, consistent with previous findings. We further characterised a pectinesterase (PE), a cell wall degrading enzyme, and INF4, a PAMP-like protein. Both were highly expressed early in infection, enhanced P. infestans colonization, and secreted at haustoria. Notably, in P. infestans transformed lines, PE-mRFP accumulated around the base of haustoria while INF4-mRFP was found to envelop the whole haustorium. We propose that the haustorium is a major site for both non-conventional and conventional secretion, and cell wall degrading enzymes and PAMP proteins are secreted at these sites to facilitate pathogenicity in P. infestans.

INSTRUMENT(S): LTQ Orbitrap

ORGANISM(S): Phytophthora Infestans T30-4

SUBMITTER: shumei wang  

LAB HEAD: Paul RJ Birch

PROVIDER: PXD009802 | Pride | 2018-09-03

REPOSITORIES: Pride