Accumulation of phytoalexins in potato tuber treated with plant extract

One of the best and longest-studied defense responses of plants to infection is the induced accumulation of antimicrobial, low-molecular-weight secondary metabolites known as phytoalexins. A role for these compounds in defense has been revealed through several experimental approaches. Samples of Olea europeae L. leaves were collected from Béjaia in January 2009. The whole samples were dried in shade and crushed to fine powder. 20g of dried powder of olive leaves were submitted to extractions which were carried out twice for 24h with 400 mL of ethanol according to Ranalli et al (2006). The total phenolic contents of the samples were determined with the Folin Ciocalteu reagent. The half tuber cultivars Desiree and Spunta, was treated by depositing 100µl of one of the previously prepared phenolic extracts in the hole drilled with a cork as described by val et al. (2006). They were then inoculated with an inoculum of Pectobacterium atrosepticum (108 cfu/ml). The tubers were assessed after five days for the development of diseases symptoms, and were used to evaluate production of phytoalexin The rate of phytoalexins in relation to cessation of pathogen development, quantification of phytoalexins at the infection site, of potato tubers treated with plant extract was studied. The results of the half-tuber inoculation treated by various extracts showed a remarkable reduction in the amount of rotted tissue. Evidence in support of phytoalexins in resistance as well some recent advances in phytoalexin biosynthesis are reviewed. Criteria for evaluating a role for phytoalexins in disease resistance are also discussed.

Keywords: Phytoalexins, potato tubers, protection, plant extracts

References: Ranalli. et al. (2006.) J Agric Food Chem 54: 434–440.

Val F et al D (2006) Phytoma, la défense des végétaux 596: 33–36