title: Molecular phylogeny, pathogenicity and toxigenicity of Fusarium oxysporum f. sp. lycopersici.
abstract: The present study aimed at the molecular characterization of pathogenic and non pathogenic F. oxysporum f. sp. lycopersici strains isolated from tomato. The causal agent isolated from symptomatic plants and soil samples was identified based on morphological and molecular analyses. Pathogenicity testing of 69 strains on five susceptible tomato varieties showed 45% of the strains were highly virulent and 30% were moderately virulent. Molecular analysis based on the fingerprints obtained through ISSR indicated the presence of wide genetic diversity among the strains. Phylogenetic analysis based on ITS sequences showed the presence of at least four evolutionary lineages of the pathogen. The clustering of F. oxysporum with non pathogenic isolates and with the members of other formae speciales indicated polyphyletic origin of F. oxysporum f. sp. lycopersici. Further analysis revealed intraspecies variability and nucleotide insertions or deletions in the ITS region among the strains in the study and the observed variations were found to be clade specific. The high genetic diversity in the pathogen population demands for development of effective resistance breeding programs in tomato. Among the pathogenic strains tested, toxigenic strains harbored the Fum1 gene clearly indicating that the strains infecting tomato crops have the potential to produce Fumonisin.
authors.affiliation: Department of Microbiology and Biotechnology, Jnanabarathi Campus, Bangalore University, Bangalore, Karnataka, India.
authors.forename: D
authors.initials: D
authors.lastname: Nirmaladevi
authors.affiliation: DRDO-BU-CLS, Barathiar University Campus, Coimbatore, Tamil Nadu, India.
authors.forename: M
authors.initials: M
authors.lastname: Venkataramana
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, India.
authors.forename: Rakesh K
authors.initials: RK
authors.lastname: Srivastava
authors.affiliation: Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India.
authors.forename: S R
authors.initials: SR
authors.lastname: Uppalapati
authors.affiliation: Molecular Glycobiotechnology Group, Discipline of Biochemistry, School of Natural Sciences, National University of Ireland, Galway, Ireland.
authors.forename: Vijai Kumar
authors.initials: VK
authors.lastname: Gupta
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Yli-Mattila
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of British Columbia, Canada.
authors.forename: K M
authors.initials: KM
authors.lastname: Clement Tsui
authors.affiliation: Department of Microbiology and Biotechnology, Jnanabarathi Campus, Bangalore University, Bangalore, Karnataka, India.
authors.forename: C
authors.initials: C
authors.lastname: Srinivas
authors.affiliation: DOS in Biotechnology, University of Mysore, Manasagangothri, Mysore, Karnataka, India.
authors.forename: S R
authors.initials: SR
authors.lastname: Niranjana
authors.affiliation: DOS in Biotechnology, University of Mysore, Manasagangothri, Mysore, Karnataka, India.
authors.forename: Nayaka S
authors.initials: NS
authors.lastname: Chandra
mesh_terms: D021901:DNA, Intergenic; D005670:Fusarium / Q000145:classification* / Q000502:physiology*; D014644:Genetic Variation; D005838:Genotype; D018551:Solanum lycopersicum / Q000382:microbiology; D018895:Microsatellite Repeats; D058889:Molecular Typing; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D014774:Virulence
chemical_list: D021901:DNA, Intergenic