Fusarium wilt infection in melon: a transcriptomic approach to characterize the genetic dialogue between host and pathogen

Fusarium oxysporum f. sp. melonis (Fom) causes Fusarium wilt of melon which is an economically important disease worldwide. The most effective control measure to prevent Fusarium wilt is through host resistance. Four races of Fom are presently known (0, 1, 2, and 1.2), one of which, race 1.2, is able to overcome the resistance of commonly cultivated varieties. No genes have been identified in melon that confer high levels of resistance to race 1.2. A transcriptomic approach has been undertaken by cDNA-AFLP on melon plants of the cultivar ‘Charentais Fom-2’ infected with race 1 (avirulent) and race 1.2 (virulent), at five time points, and the experiment was concluded 21 days after inoculation. The RNA from fungal colonies of the two races was also included into the analysis, to improve the identification of possible fungal transcripts expressed in the host during infection. Preliminary analysis of expression profiles brought to 500 differentially expressed bands which were selected as corresponding to: a) genes modulated in the incompatible interaction or b) in the compatible interaction only; c) genes modulated in both interactions with different profiles; d) genes expressed in plant, but showing a band of similar size also in the fungal samples, which might be of fungal origin. Fragments of cDNA eluted from the gels and sequenced, were searched for homology in databases. Differences in gene expression have been detected between cDNA-AFLP profiles of virulent and avirulent races grown in culture, which represent the basis for races 1 and 1.2 characterization.Cucurbitaceae 2008. IX EUCARPIA Meeting. Avignon (France), May 21-24th, 200