Etude du polymorphisme génétique chez l'orobanche de la fève: Orobanche crenata Forskall. en Algérie, par l'utilisation des marqueurs moléculaires RAPD et AFLP

Abstract

Orobanche crenata is an obligatory parasitic plant of broad bean and other leguminous cultures, and generates serious damages on these cultures. Molecular approach by the use of three techniques of marking: SDS-PAGE, RAPD and AFLP was privileged in this study. The principal objective of this work, is to determine the intraspecific level of diversity, among populations of O crenata collected in various geographical localities of the Mitidja in Algeria, and to highlight interspecific polymorphism between the three most widespread species of broomrape in Algeria, namely O crenata O ramosa and O aegyptiaca The second objective is to study the effectiveness of the two types of DNA markers, RAPDs and AFLPs, in the detection of interspecific and intraspecific genetic polymorphism. The electrophoresis of native proteins of broomrape's seeds in SDS-PAGE, generated a relatively similar electrophoretic profiles between the various analyzed ecotypes of O.crenata. The comparison between the latter and those of O.ramosa revealed an obvious and clear difference. The interspecific and intraspecific genetic polymorphism was highlighted through the use of the two techniques of DNA marking, the RAPD and the AFLP. On the whole, 144 RAPDs markers were identified among the six ecotypes of O.crenata and O.aegyptiaca through which we could distinguish the two sections to which the two species belong, namely the Tryonikon section for O.aegyptiaca and the Osproléon section for O.crenata. The DNA analysis by the use of AFLP also revealed a notable polymorphism between the various ecotypes tested. On the whole, 429 AFLP markers were generated with 3 combined primers. The AFLP produced a better resolution of the analyzed genomic profiles. This technique proved more precise and more sensitive than the RAPD in the detection of polymorphism between very close genotypes.