Fusarium oxysporum f. sp. albedinis Toxin Characterization and Use for Selection of Resistant Date Palm to Bayoud Disease

Abstract

Date palm (Phoenix dactylifera L.) is the most economically important food crop in Moroccan oasean agricultural areas, contributing to preserving an arid ecosystem threatened by desertification. The bayoud disease, caused by the fungus Fusarium oxysporum f. sp. albedinis (Foa), is incontestably the most serious disease affecting date palm in North Africa. The selection for resistance among date palm cultivars was the preferred way to control the disease. New performing cultivars were selected, mass propagated and distributed to farmers. The use of pathogen toxins in in vitro selection is an innovative approach for rapid screening for resistance to bayoud disease. This chapter gives an overview of recent knowledge about toxins and other substances produced by plant pathogenic fungi and their applications in in vitro and in vivo selection for resistance. Foa toxins contain fusaric acid and other toxic fractions. These fractions of toxins have some chemical and biological characteristics that differ from among other fractions isolated from other pathogenic and nonpathogenic strains of F. oxysporum. These toxins could be exploited for pre-selection of plants for resistance to bayoud among populations of plants originating from either irradiated tissue culture or conventional breeding programs.