title: Differential effects of fenpropimorph and fenhexamid, two sterol biosynthesis inhibitor fungicides, on arbuscular mycorrhizal development and sterol metabolism in carrot roots.
abstract: Sterols composition of transformed carrot roots incubated in presence of increasing concentrations of fenpropimorph (0.02; 0.2; 2mgl(-1)) and fenhexamid (0.02; 0.2; 2; 20mgl(-1)), colonized or not by Glomus intraradices was determined. In mycorrhizal roots treated with fenpropimorph, normal Delta(5)-sterols were replaced by unusual compounds such as 9beta,19-cyclopropylsterols (24-methylpollinastanol), Delta(8,14)-sterols (ergosta-8,14-dienol, stigmasta-8,14-dienol), Delta(8)-sterols (Delta(8) sitosterol) and Delta(7)-sterols (ergosta-7,22-dienol). After application of fenpropimorph, a drastic reduction of the mycorrhizal root growth, root colonization and extraradical fungal development was observed. Application of fenhexamid did not modify sterol profiles and the total colonization of roots. But the arbuscule frequency of the fungal partner was significantly affected. Comparison of the effects caused by the tested fungicides indicates that the usual phytosterols may be involved in symbiosis development. Indeed, observed modifications of root sterols composition could explain the high fenpropimorph toxicity to the AM symbiosis. However, the absence of sterolic modifications in the roots treated with fenhexamid could account for its more limited impact on mycorrhization.
authors.affiliation: Université du Littoral Côte d'Opale, Laboratoire de Mycologie Phytopathologie Environnement, Calais, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Campagnac
authors.forename: Joël
authors.initials: J
authors.lastname: Fontaine
authors.forename: Anissa Lounès-Hadj
authors.initials: AL
authors.lastname: Sahraoui
authors.forename: Frédéric
authors.initials: F
authors.lastname: Laruelle
authors.forename: Roger
authors.initials: R
authors.lastname: Durand
authors.forename: Anne
authors.initials: A
authors.lastname: Grandmougin-Ferjani
mesh_terms: D000577:Amides / Q000494:pharmacology*; D018552:Daucus carota / Q000382:microbiology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005659:Fungicides, Industrial / Q000494:pharmacology; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D009025:Morpholines / Q000494:pharmacology*; D038821:Mycorrhizae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D010840:Phytosterols / Q000096:biosynthesis*; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology
chemical_list: D000577:Amides; D005656:Fungal Proteins; D005659:Fungicides, Industrial; D009025:Morpholines; D010840:Phytosterols; C050435:fenpropimorph; C451426:N-(2,3-dichloro-4-hydroxyphenyl)-1-methylcyclohexanecarboxamide