Phytoalexins

Phytoalexins are low molecular weight antimicrobial compounds that are produced by plants asa response to biotic and abiotic stresses. As such they take part in an intricate defense system whichenables plants to control invading microorganisms. In the 1950s, research on phytoalexins startedwith progress in their biochemistry and bio-organic chemistry, resulting in the determination of theirstructure, their biological activity, as well as mechanisms of their synthesis and catabolism bymicroorganisms. Elucidation of the biosynthesis of numerous phytoalexins also permitted the use ofmolecular biology tools for the exploration of the genes encoding enzymes of their synthesispathways and their regulators. This has led to potential applications for increasing plant resistance todiseases. Phytoalexins display an enormous diversity belonging to various chemical families such asfor instance, phenolics, terpenoids, furanoacetylenes, steroid glycoalkaloids, sulfur-containingcompounds and indoles.Research and review papers dealing with numerous aspects of phytoalexins including modulationof their biosynthesis, molecular engineering in plants, biological activities, structure/activityrelationships and phytoalexin metabolism by micro-organisms are published in this issue.