Genetic diversity of Fusarium oxysporum and related species pathogenic on tomato in Algeria and other Mediterranean countries

Abstract

In order to characterize the pathogen(s) responsible for the outbreak of fusarium diseases in Algeria, 48 Fusarium spp. isolates were collected from diseased tomato in Algeria and compared with 58 isolates of Fusarium oxysporum originating from seven other Mediterranean countries and 24 reference strains. Partial sequences of the translation elongation factor EF1a gene enabled identification of 27 isolates as F. oxysporum, 18 as F. commune and three as F. redolens among the Algerian isolates. Pathogenicity tests confirmed that all isolates were pathogenic on tomato, with disease incidence greater at 28°C than at 24°C. All isolates were characterized using intergenic spacer (IGS) DNA typing, vegetative compatibility group (VCG) and PCR detection of the SIX1 (secreted in xylem 1) gene specific to F. oxysporum f. sp. lycopersici (FOL). No DNA polymorphisms were detected in the isolates of F. redolens or F. commune. In contrast, the 27 Algerian isolates of F. oxysporum were shown to comprise nine IGS types and 13 VCGs, including several potentially new VCGs. As none of the isolates was scored as SIX1+, the 27 isolates could be assigned to F. oxysporum f. sp. radicis-lycopersici (FORL). Isolates from Tunisia were also highly diverse but genetically distinct from the Algerian isolates. Several Tunisian isolates were identified as FOL by a PCR that detected the presence of SIX1. The results show that isolates from European countries were less diverse than those from Tunisia. Given the difference between Algerian populations and populations in other Mediterranean countries, newly emergent pathogenic forms could have evolved from local non-pathogenic populations in Algeria.

Identification and Characterization of Fusarium Species Associated with Wilt of Eleocharis dulcis (Chinese water chestnut) in China

“…DNA sequences from the mtSSU or EF-1α regions were useful to distinguish F. commune from F. oxysporum on host plants of soybean, Douglas-fir, tomato, and horseradish (4,6,31,32). Phylogenetic analyses of the individual or the combined mtSSU and EF-1α sequences have identified F. commune as a sister taxon of F. oxysporum (4,6,31,32). The phylogenetic analyses of three regions (mtSSU, EF-1α, and IGS) in this study all indicated that F. commune is in a separate clade, clearly distinct from the FOSC (Fig.…”

Morphological and molecular characterization of Fusarium spp. associated with yellowing disease of black pepper (Piper nigrum L.) in Malaysia

“…The roots were then wounded with a sterile knife, immersed in a spore suspension (1 9 10 6 spores/mL) for 5 min, swirled several times and transplanted into pots containing 4 kg sterilized soil mixture (3:2:1 v/v ratio of top soil-peat moss-sand). After transplanting, each pot was inoculated by drenching the soil around the crown with 200 mL of the same spore suspensions (1 9 10 6 spores/ mL) used for root infection (Edel-Hermann et al 2011). As a control, roots were wounded and dipped in distilled water, transplanted into pots with sterilized soil and treated with 200 mL sterilized distilled water.…”

Fusarium diversity in soil using a specific molecular approach and a cultural approach

“…They have revealed the high level of phylogenetic diversity within several morphological species such as F. oxysporum and Fusarium solani, which are now recognized as species complexes. Among useful loci, the translation elongation factor 1-alpha (EF-1α) gene allowed both to differentiate closely related species and to reveal intraspecific polymorphism (O'Donnell et al, 2009(O'Donnell et al, , 2012Edel-Hermann et al, 2012) and can be used as a BLAST query against the FUSARIUM-ID sequence database (Geiser et al, 2004) or the Fusarium MLST database (O'Donnell et al, 2012).…”