24‐Methyl/methylene sterols increase in monoxenic roots after colonization by arbuscular mycorrhizal fungi

Abstract

Summary• Characteristic sterols of transformed carrot ( Daucus carota ) and chicory ( Cichorium intybus ) roots colonized by different strains of arbuscular mycorrhizal (AM) fungi were identified.• Sterols were extracted, analysed and identified by gas chromatography/mass spectrometry (GC-MS) from monoxenic cultures of mycorrhizal and nonmycorrhizal roots. After colonization by Glomus intraradices , Glomus proliferum and Glomus sp., carrot and chicory roots exhibited a significantly higher 24-methyl/methylene sterol content. A correlation was established between the content of the sum of 24-methyl cholesterol, 24-methylene cholesterol and 24-methyl desmosterol.• This study clearly established that the increment of these characteristic sterols is an appropriate indicator of colonization by AM fungi of transformed roots.• Metabolic origin and specificity of these sterols in mycorrhizal roots was researched. The 24-methyl/methylene sterol increase was observed only when the interaction between fungus and plant was completely established and the fungus was present inside the roots.

Lipid content disturbance in the arbuscular mycorrhizal, Glomus irregulare grown in monoxenic conditions under PAHs pollution

“…Contrarily to the most fungi, no ergosterol was found in the AMF. This result is in accordance with previous studies reporting Glomus intraradices sterol composition (GrandmouginFerjani et al 1999(GrandmouginFerjani et al , 2005Fontaine et al 2004, Campagnac et al 2009). PAHs treatments induced a significant decrease of G. irregulare total sterol content due mainly to a drastic drop of 24-methycholesterol.…”

Metabolite profiling of mycorrhizal roots of Medicago truncatula

“…Its level, together with 24-methylene cholesterol, correlated with the degree of mycorrhization in maize and onions (Schmitz et al, 1991). Also in G. intraradices, campesterol was dominant with sitosterol, fucosterol and cholesterol as minor components, whereas ergosterol was not found (Fontaine et al, 2004). In the past, there was a debate on the occurrence and distribution of ergosterol in AM fungi due to frequent contamination with saprophytic fungi of high ergosterol contents.…”

Role of arbuscular mycorrhizal symbiosis in root mineral uptake under CaCO3 stress

“…The second experiment consisted in cultivating transformed chicory roots by Agrobacterium rhizogenes (Fontaine et al 2004) colonized or not by R. irregularis on a modified M medium containing or not the same CaCO 3 concentrations as used in the first experiment. Cultures were inoculated from standardized root inoculum of 2-month-old monoxenic cultures of Ri T-DNA transformed chicory roots, colonized or not by R. irregularis, sampled using a 10-mm cork borer as described by Verdin et al (2006).…”