Phytoparasitica (1999) 27 (1) - Development of specific ...
A. Chiocchetti, S. Ghignone, I. Bernardo, L. Sciaudone, M.L. Gullino, A. Garibaldi and Q. Migheli (1999)
Development of specific primers for PCR detection of Fusarium oxysporum f.sp. basilici
Phytoparasitica 27 (1)
Workshop on Genetic Aspects of Fusarium oxysporum and Related Species, Jerusalem, Israel
Abstract: Wilt and crown rot of sweet basil, caused by Fusarium oxysporum f.sp. basilici (Fob), represents a major problem with this crop. Fusarium wilt management relies on the integration of different control measures, such as soil and substrate disinfestation, raised bench cultivation, seed dressing and the use of antagonistic Fusarium spp. However, soil contamination through infected seed and airborne propagules makes soil disinfestation only partially effective against Fob. Low efficacy of chemical control, the limited availability of resistant cultivars and the unsatisfactory level of control through commercial formulations of biocontrol agents, boost the urgency for seed and transplant certification procedures with sweet basil. The aim of this research was to design a reliable and rapid method for the unequivocal recognition of Fob isolated from contaminated basil seed, plants and infested soil. Fifty-two isolates of Fusarium oxysporum, obtained from infected basil plants, seeds, flower residues and soil from different growing areas in Italy and Israel, were analyzed by random amplification of polymorphic DNA (RAPD-PCR), coupled to a DNA extraction protocol from colonies grown on a Fusarium-selective medium. In a pathogenicity assay, 35 isolates determined 32-92% of diseased seedlings on the highly susceptible basil cultivar 'Fine Verde' 21 days after sowing in an artificially infested substrate, whereas 17 isolates were nonpathogenic on basil. All Fob isolates gave identical amplification patterns by using 31 different random primers. All tested primers allowed the clear differentiation of Fob from representatives of other formae speciales or from non-pathogenic strains of F. oxysporum. Several amplification products were eluted from gel, digoxigenin-labeled and tested for Fob-specificity in a dot blot assay. A 1 kb amplimer hybridized only to DNA from all Fob isolates but not to DNA from other F. oxysporum isolates or from representatives of F. redolens, F. tabacinum, Rhizoctonia solani, Sclerotinia sclerotiorum, S. minor and Pythium ultimum. This DNA fragment was cloned in pGEM-T, subcloned in pBS-SK and sequenced. Two pairs of Fob-specific primers were designed based on these sequences, giving rise to amplification products of 381 and 331 bp, respectively. The two primer sets allowed PCR identification of the pathogen in infected plants, in naturally and artificially infected seeds and in infested soil samples.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Quirico Migheli
Research topic(s) for pests/diseases/weeds:
identification/taxonomy
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Fusarium oxysporum f.sp. basilici | Basil (Ocimum) | Italy | ||
| Fusarium oxysporum f.sp. basilici | Basil (Ocimum) | Israel | ||
| Fusarium oxysporum |
