Résumé:
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.
