Metabolic priming by a secreted fungal effector

• Published in: Nature (London) 2011-10, Vol.478 (7369), p.395-398
• Main Authors: Djamei, Armin, Schipper, Kerstin, Rabe, Franziska, Ghosh, Anupama, Vincon, Volker, Kahnt, Jörg, Osorio, Sonia, Tohge, Takayuki, Fernie, Alisdair R., Feussner, Ivo, Feussner, Kirstin, Meinicke, Peter, Stierhof, York-Dieter, Schwarz, Heinz, Macek, Boris, Mann, Matthias, Kahmann, Regine
• Format: Article
• Language: English
• Subjects: 631/326/193/2544; 631/449/1736; 631/449/2169/2673; Biological and medical sciences; Biosynthesis; Chorismate Mutase - metabolism; Cytoplasm - enzymology; Enzymes; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Gene Expression Regulation, Plant; Genetic Complementation Test; Host-Pathogen Interactions; Humanities and Social Sciences; letter; Metabolome; Methods; Models, Biological; multidisciplinary; Nematoda; Phytopathology. Animal pests. Plant and forest protection; Plant Proteins - metabolism; Plant tissues; Plastids - enzymology; Protein Multimerization; Proteins; Saccharomyces cerevisiae - genetics; Salicylic Acid - metabolism; Science; Science (multidisciplinary); Two-Hybrid System Techniques; Ustilago - enzymology; Ustilago - pathogenicity; Ustilago maydis; Virulence Factors - genetics; Virulence Factors - metabolism; Zea mays; Zea mays - metabolism; Zea mays - microbiology
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature10454

How maize smut fungus softens up its host The fungal pathogen Ustilago maydis , known as maize (corn) smut, induces plant tumours through the action of effectors that are translocated into the plant tissue. One of these effectors is now shown to be a chorismate mutase, Cmu1. The enzyme is taken up by the host plant cells where it lowers salicylic acid levels, priming them for a successful infection. Inactivation of Cmu1 abolishes virulence, suggesting an interesting new target for disease intervention. Many plant pathogens encode secreted chorismate mutases, indicating a widely used mechanism. Maize smut caused by the fungus Ustilago maydis is a widespread disease characterized by the development of large plant tumours. U. maydis is a biotrophic pathogen that requires living plant tissue for its development and establishes an intimate interaction zone between fungal hyphae and the plant plasma membrane. U. maydis actively suppresses plant defence responses by secreted protein effectors 1 , 2 . Its effector repertoire comprises at least 386 genes mostly encoding proteins of unknown function 1 , 3 , 4 and expressed exclusively during the biotrophic stage 3 . The U. maydis secretome also contains about 150 proteins with probable roles in fungal nutrition, fungal cell wall modification and host penetration as well as proteins unlikely to act in the fungal-host interface 4 like a chorismate mutase. Chorismate mutases are key enzymes of the shikimate pathway and catalyse the conversion of chorismate to prephenate, the precursor for tyrosine and phenylalanine synthesis. Root-knot nematodes inject a secreted chorismate mutase into plant cells likely to affect development 5 , 6 . Here we show that the chorismate mutase Cmu1 secreted by U. maydis is a virulence factor. The enzyme is taken up by plant cells, can spread to neighbouring cells and changes the metabolic status of these cells through metabolic priming. Secreted chorismate mutases are found in many plant-associated microbes and might serve as general tools for host manipulation.