Differentially expressed TDFs by cDNA-AFLP in tomato infected withFusarium oxysporumf.sp. lycopersici

To elucidate the tomato defense responses during the interaction of tomato and Fusarium oxysporum f. sp. lycopersici (Fol), a cDNA-AFLP experiment of the fungal-induced changes at the transcriptional level was performed to identify up- or down-regulated genes. Transcript derived fragments (TDF) from leaves, stems and roots were used for accurate gene expression profiles by visual observation and analysis of bands and their intensities in Fol infected and non-infected tomato lines (AVTO 9802 and AVTO 1002). Using 10 AFLP primer combinations, an average of 163 scored TDFs was identified as differentially expressed genes, corresponding to about 55.7% of all visualized transcripts. These TDFs were consistent with the extensive physiological changes that affect infected tissues from leaves, stems and roots. Although most of the visualized transcripts were affected by infection, about 46.6% of the identified differentially expressed TDFs were down-regulated during infection, possibly reflecting the management of cellular resources and/or the repression of defense responses. Understanding the defense mechanism of plant against pathogens would significantly assist in the development of new resistant tomato cultivars.