séminaire Agroécologie

"Carotenoid metabolism and function in mycorrhizal roots" - Michael H. Walter, Leibnitz-Institut fur Pflanzenbiochemie à Halle, Allemagne - mardi 14 septembre à 9h, salle de Conférences, INRA










Plant roots colonized by arbuscular mycorrhizal (AM) fungi  accumulate a yellow C14 apocarotenoid called mycorradicin and other C13 derivatives of carotenoid cleavage. We have investigated C13/C14 apocarotenoid biosynthesis in AM-colonized roots of Medicago truncatula and have characterized several biosynthetic steps catalyzed by MEP pathway enzymes (DXS2, DXR) as well as carotenoid cleavage steps (CCD1, CCD7). Knockdown approaches on MtDXS2 and MtCCD1 have shown that manipulating the apocarotenoid pathway can profoundly alter apocarotenoid accumulation and root color, AM marker gene expression, AM functionality and the relative distribution of the various stages of arbuscule development. Based on molecular and cell biological data a model for C13 apocarotenoid mode of action in the AM symbiosis is proposed.