Identification of the caffeoylshikimic acids in the roots of the date palm, principle fungitoxic compounds vis-a-vis Fusarium-oxysporum f sp albedinis

5-caffeoylshikimic acid and its isomeres of position (dactylifric acid) found in the roots of date-palms (Phoenix dactylifera L.) inhibit the germination of conidia and the growth of the mycelium of Fusarium oxysporum f. sp. albedinis. The acid content accumulated in resistant cultivars are toxic to fungi, whereas that accumulated in sensitive cultivars does not seem to affect growth and development of the parasite. This well demonstrates the implication of caffeoylshikimic acid in the resistance of the date-palm to this fusarium disease. Moreover, these results will be of great use, especially for screening resistant genotypes obtained from directed crossings or from in vitro cultures.