A small, cysteine‐rich protein secreted by Fusarium oxysporum during colonization of xylem vessels is required for I‐3‐mediated resistance in tomato

• Published in: Molecular microbiology 2004-09, Vol.53 (5), p.1373-1383
• Main Authors: Rep, Martijn, Van Der Does, H. Charlotte, Meijer, Michiel, Van Wijk, Ringo, Houterman, Petra M., Dekker, Henk L., De Koster, Chris G., Cornelissen, Ben J. C.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Biological and medical sciences; Cysteine - metabolism; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - secretion; Fusarium - genetics; Fusarium - metabolism; Fusarium - pathogenicity; Fusarium oxysporum; Immunity, Innate; Lycopersicon esculentum; Lycopersicon esculentum - anatomy & histology; Lycopersicon esculentum - microbiology; Lycopersicon esculentum - physiology; Microbiology; Miscellaneous; Molecular Sequence Data; Mycology; Mycoses - metabolism; Transformation, Genetic
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2004.04177.x

Summary A 12 kDa cysteine‐rich protein is secreted by Fusarium oxysporum f. sp. lycopersici during colonization of tomato xylem vessels. Peptide sequences obtained with mass spectrometry allowed identification of the coding sequence. The gene encodes a 32 kDa protein, designated Six1 for secreted in xylem 1. The central part of Six1 corresponds to the 12 kDa protein found in xylem sap of infected plants. A mutant that had gained virulence on a tomato line with the I‐3 resistance gene was found to have lost the SIX1 gene along with neighbouring sequences. Transformation of this mutant with SIX1 restored avirulence on the I‐3 line. Conversely, deletion of the SIX1 gene in a wild‐type strain results in breaking of I‐3‐mediated resistance. These results suggest that I‐3‐mediated resistance is based on recognition of Six1 secreted in xylem vessels.