Salicylic acid (SA) plays a key role in establishing resistance to pathogens in many plants. To study the
possible involvement of SA in the resistance of date palm (Phoenix dactylifera L.) to Fusarium oxysporum f. sp.
albedinis (FOA), we investigated levels of phenolic compounds, known as indicators of resistance in the date palm/
Fusarium pathosystem. After treatment with SA the content of root soluble phenolics in F. oxysporum inoculated
date palm seedlings was about 4 times higher in cv. Bousthami noir and 6 times higher in cv. Jihel than that in
untreated plants showing disease symptoms. The largest increase was at a SA concentration of 50 µM. SA treatment
also enhanced the content of cell wall phenolics. In addition, inoculation of SA-treated roots of date palm with FOA
(strain ZAG) resulted in a greater number of plants showing only limited hypersensitive reaction-like necrotic lesions.
In contrast, SA-untreated plants normally showed spreading necrosis in response to fungus inoculation
