title: Chitin synthase-deficient mutant of Fusarium oxysporum elicits tomato plant defence response and protects against wild-type infection.
abstract: A mutant of the root pathogen Fusarium oxysporum f. sp. lycopersici, deficient in class V chitin synthase, has been shown previously to be nonvirulent. In this study, we tested the hypothesis that the cause of its avirulence could be the elicitation of the induced plant defence response, leading to the restriction of fungal infection. Co-inoculation of tomato plants with the wild-type strain and the DeltachsV mutant resulted in a significant reduction in symptom development, supporting a protective mechanism exerted by the mutant. The ability of the mutant to penetrate and colonize plant tissues was determined by scanning and transmission electron microscopy, as well as fluorescence microscopy using green fluorescent protein- or cherry fluorescent protein-labelled fungal strains. The extent of wild-type strain colonization in co-inoculated plants decreased steadily throughout the infection process, as shown by the quantification of fungal biomass using real-time polymerase chain reaction. The hypothesis that defence responses are activated by the DeltachsV mutant was confirmed by the analysis of plant pathogenesis-related genes using real-time reverse transcriptase-polymerase chain reaction. Tomato plants inoculated with the DeltachsV mutant showed a three fold increase in endochitinase activity in comparison with wild-type inoculated plants. Taken together, these results suggest that the perturbation of fungal cell wall biosynthesis results in elicitation of the plant defence response during the infection process.
authors.affiliation: Departamento de Genética, Universidad de Córdoba, Edificio C5, Campus de Rabanales, 14071 Córdoba, Spain.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Pareja-Jaime
authors.forename: Magdalena
authors.initials: M
authors.lastname: Martín-Urdíroz
authors.forename: María Isabel González
authors.initials: MI
authors.lastname: Roncero
authors.forename: José Antonio
authors.initials: JA
authors.lastname: González-Reyes
authors.forename: María Del Carmen Ruiz
authors.initials: Mdel C
authors.lastname: Roldán
mesh_terms: D002687:Chitin Synthase / Q000172:deficiency / Q000235:genetics*; D002688:Chitinases / Q000235:genetics / Q000378:metabolism; D005670:Fusarium / Q000201:enzymology* / Q000235:genetics* / Q000276:immunology; D018551:Solanum lycopersicum / Q000276:immunology / Q000382:microbiology*; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology
chemical_list: D002687:Chitin Synthase; D002688:Chitinases