The arbuscular mycorrhizal Rhizophagus irregularis activates storage lipid biosynthesis to cope with the benzo[a]pyrene oxidative stress.
The phytoremediation assisted by arbuscular mycorrhizal fungi (AMF) could constitute an ecological and economic method to restore polycyclic aromatic hydrocarbon (PAH) polluted soils. Unfortunately, little is known about the PAH impact on the beneficial symbiotic AMF. Using radiolabelling experiments, our work aims to understand how benzo[a]pyrene (B[a]P), a representative of high molecular weight PAH, acts on the AMF lipid metabolism. Our results showed decreases in the sterol precursors as well as in total phospholipid quantities, in link with the [1-(14)C]acetate incorporation decreases in these lipids. Interestingly, a concomitant increase of [1-(14)C]acetate incorporation by 29.5% into phosphatidylcholine with its content decrease in Rhizophagus irregularis extraradical mycelium was observed, suggesting a membrane regeneration. A second concomitant increase (estimated to 69%) of [1-(14)C]acetate incorporation into triacylglycerols (TAG) with the content decrease was also observed. This suggests a fungal TAG biosynthesis activation probably to offset the decrease in storage lipid content when the fungus was grown under B[a]P pollution. In addition, our findings showed that lipase activity was induced by more than 3 fold in the presence of B[a]P in comparison to the control indicating that the drop in TAG content could be a consequence of their active degradation. Taken together, our data suggest the involvement of the fungal TAG metabolism to cope B[a]P toxicity through two means: (i) by providing carbon skeletons and energy necessary for membrane regeneration and/or for B[a]P translocation and degradation as well as (ii) by activating the phosphatidic acid and hexose metabolisms which may be involved in cellular stress defence.
Univ Lille Nord de France, F-59000 Lille, France; Université du Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV), 50, rue Ferdinand Buisson, F-62228 Calais, France.
Maryline
M
Calonne
Univ Lille Nord de France, F-59000 Lille, France; Université du Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV), 50, rue Ferdinand Buisson, F-62228 Calais, France.
Joël
J
Fontaine
Univ Lille Nord de France, F-59000 Lille, France; Université du Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV), 50, rue Ferdinand Buisson, F-62228 Calais, France.
Djouher
D
Debiane
Univ Lille Nord de France, F-59000 Lille, France; Université du Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV), 50, rue Ferdinand Buisson, F-62228 Calais, France.
Frédéric
F
Laruelle
Univ Lille Nord de France, F-59000 Lille, France; Université du Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV), 50, rue Ferdinand Buisson, F-62228 Calais, France.
Anne
A
Grandmougin-Ferjani
Univ Lille Nord de France, F-59000 Lille, France; Université du Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV), 50, rue Ferdinand Buisson, F-62228 Calais, France. Electronic address: lounes@univ-littoral.fr.
Anissa
A
Lounès-Hadj Sahraoui
D000465:Algorithms; D001564:Benzo(a)pyrene / Q000737:chemistry / Q000494:pharmacology*; D001673:Biodegradation, Environmental; D005227:Fatty Acids / Q000378:metabolism*; D005658:Fungi / Q000378:metabolism; D055137:Glomeromycota / Q000378:metabolism; D008049:Lipase / Q000378:metabolism*; D025282:Mycelium / Q000378:metabolism; D038821:Mycorrhizae; D018384:Oxidative Stress / Q000187:drug effects; D018517:Plant Roots / Q000382:microbiology; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D013261:Sterols / Q000378:metabolism
D005227:Fatty Acids; D011084:Polycyclic Aromatic Hydrocarbons; D013261:Sterols; D001564:Benzo(a)pyrene; D008049:Lipase
AMF; Arbuscular mycorrhizal fungi (AMF); B[a]P; Benzo[a]pyrene (B[a]P); Extraradical mycelium; FA; FC; HPLC; LSA; Lipids; MDA; PA; PAH; PC; PE; PG; PL; PS; Polycyclic aromatic hydrocarbons (PAH); RC; SDS; TAG; TLC; [1-(14)C]acetate; arbuscular mycorrhizal fungi; benzo[a]pyrene; fatty acids; fungal compartment; high pressure liquid chromatography; liquid scintillation analyzer; malondialdehyde; phosphatidic acid; phosphatidylcholine; phosphatidylethanolamine; phosphatidylglycerol; phosphatidylserine; phospholipid(s); polycyclic aromatic hydrocarbons; root compartment; sodium dodecyl sulphate; thin-layer chromatography; triacylglycerols