title: The maize cystatin CC9 interacts with apoplastic cysteine proteases.
abstract: In a recent study we identified corn cystain9 (CC9) as a novel compatibility factor for the interaction of the biotrophic smut fungus Ustilago maydis with its host plant maize. CC9 is transcriptionally induced during the compatible interaction with U. maydis and localizes in the maize apoplast where it inhibits apoplastic papain-like cysteine proteases. The proteases are activated during incompatible interaction and salicylic acid (SA) treatment and, in turn, are sufficient to induce SA signaling including PR-gene expression. Therefore the inhibition of apoplastic papain-like cysteine proteases by CC9 is essential to suppress host immunity during U. maydis infection. Here were present new experimental data on the cysteine protease-cystatin interaction and provide an in silco analysis of plant cystatins and the identified apoplastic cysteine proteases.
authors.affiliation: Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
authors.forename: Karina
authors.initials: K
authors.lastname: van der Linde
authors.forename: André N
authors.initials: AN
authors.lastname: Mueller
authors.forename: Christoph
authors.initials: C
authors.lastname: Hemetsberger
authors.forename: Farnusch
authors.initials: F
authors.lastname: Kashani
authors.forename: Renier A L
authors.initials: RA
authors.lastname: van der Hoorn
authors.forename: Gunther
authors.initials: G
authors.lastname: Doehlemann
mesh_terms: D015891:Cystatins / Q000235:genetics / Q000378:metabolism*; D057056:Cysteine Proteases / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D014588:Ustilago / Q000472:pathogenicity*; D003313:Zea mays / Q000378:metabolism* / Q000382:microbiology
chemical_list: D015891:Cystatins; D010940:Plant Proteins; D057056:Cysteine Proteases