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.

Morphology, phylogeny and pathogenicity of Fusarium species from Sansevieria trifasciata in Malaysia

“…The genus Fusarium contains frequent pathogens or endophytes that occur in a wide range of habitats, from soil to inflorescences (Otero‐Colina et al , ; Nirmaladevi et al , ). The taxonomic classification of Fusarium species has evolved since the era of identification based solely on morphology to include recent molecular and phylogenetic approaches.…”

Diversity and identity of Fusarium species occurring on fruits, vegetables and food grains

“…cepae, F. solani and F. proliferatum with onion (KlokocarSmit et al 2008), F. musae with banana (Triest et al 2016), F. oxysporum with date palm (Elhassan 2016), F. oxysporum f. sp. lycopersici with tomato (Nirmaladevi et al 2016), etc. Figure 1 shows representative infected material from each vegetable, food grain and fruit.…”

“…In another study, Nirmaladevi et al (2016) studied the molecular phylogeny, pathogenicity and toxigenicity of various strains of F. oxysporum f. sp. lycopersici isolated from tomato.…”

Antifungal properties of Beauveria bassiana strains against Fusarium oxysporum f. sp. lycopersici race 3 in tomato crop

“…They invade the root epidermis, extend into the vascular tissues and colonize the xylem vessels. Disease symptoms appear as a result of severs water stress, mainly due to vessel clogging (Nirmaladevi et al, 2016). Use of resistant cultivars is the most reliable method for disease management.…”

“…lycopersici infecting mainly tomatoes. Tomato production is often reduced by 30 to 40%, however, sometimes it may reach up to 80% (Nirmaladevi et al, 2016). Three physiological races (1, 2 and 3) of pathogen specify are distinguished by their specific pathogenicity to tomato cultivars.…”