Synthetic Mono-Rhamnolipids Display Direct Antifungal Effects and Trigger an Innate Immune Response in Tomato against .

Natural rhamnolipids are potential biocontrol agents for plant protection against bacterial and fungal diseases. In this work, we synthetized new synthetic mono-rhamnolipids (smRLs) consisting in a rhamnose connected to a simple acyl chain and differing by the nature of the link and the length of the lipid tail. We then investigated the effects of these ether, ester, carbamate or succinate smRL derivatives on development, symptoms spreading on tomato leaves and immune responses in tomato plants.

Polyaromatic hydrocarbons impair phosphorus transport by the arbuscular mycorrhizal fungus Rhizophagus irregularis.

Phosphate uptake by plant roots is mainly mediated by arbuscular mycorrhizal fungi (AMF). However, the impact on phosphorus (P) transport of polycyclic aromatic hydrocarbons (PAH), persistent organic pollutants widely found in altered soils, is not known up today. Here, we monitored the Rhizophagus irregularis fungal growth and the fungal P transport ability from the extraradical mycelium to the host transformed chicory roots in the presence of anthracene and benzo[a]pyrene (B[a]P) and the combination of both PAH, under in vitro conditions.

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.

Benzo[a]pyrene induced lipid changes in the monoxenic arbuscular mycorrhizal chicory roots.

Arbuscular mycorrhizal (AM) colonization may be one of the means that protects plants and allows them to thrive on polycyclic aromatic hydrocarbon-polluted soils including the carcinogenic benzo(a)pyrene (B[a]P). To understand the mechanisms involved in the AM symbiosis tolerance to B[a]P toxicity, the purpose of this study was to compare the lipid compositions as well as the contents between mycorrhizal and non-mycorrhizal chicory root cultures grown in vitro under B[a]P pollution. Firstly, B[a]P induced significant decreases of the Glomalean lipid markers: C16:1ω5 and 24-methyl/methylene sterol amounts in AM roots indicating a reduced AM fungal development inside the roots.

Propiconazole inhibits the sterol 14α-demethylase in Glomus irregulare like in phytopathogenic fungi.

The increasing concentrations impact (0.02, 0.2 and 2 mg L(-1)) of a Sterol Biosynthesis Inhibitor (SBI) fungicide, propiconazole, was evaluated on development and sterol metabolism of two non-target organisms: mycorrhizal or non-mycorrhizal transformed chicory roots and the arbuscular mycorrhizal fungus (AMF) Glomus irregulare using monoxenic cultures.

Calcareous impact on arbuscular mycorrhizal fungus development and on lipid peroxidation in monoxenic roots.

The present work underlined the negative effects of increasing CaCO(3) concentrations (5, 10 and 20 mM) both on the chicory root growth and the arbuscular mycorrhizal fungus (AMF) Glomus irregulare development in monoxenic system. CaCO(3) was found to reduce drastically the main stages of G. irregulare life cycle (spore germination, germinative hyphae elongation, root colonization, extraradical hyphae development and sporulation) but not to inhibit it completely.

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

Most polycyclic aromatic hydrocarbons (PAHs) are ubiquitous natural and/or anthropogenic pollutants that have adverse effects on the human health and the environment. Little is known about their potential effects on arbuscular mycorrhizal fungi (AMF). Thus, using monoxenic cultures, this work aims to study the impact of increasing concentrations (140 and 280 μM) of two PAHs [anthracene and benzo[a]pyrene (B[a]P)] on Glomus irregulare lipid content in relation with its development.