Plants transfer lipids to sustain colonization by mutualistic mycorrhizal and parasitic fungi

Abstract

Arbuscular mycorrhizal (AM) fungi facilitate plant uptake of mineral nutrients and draw organic nutrients from the plant. Organic nutrients are thought to be supplied primarily in the form of sugars. Here we show that the AM fungus is a fatty acid auxotroph and that fatty acids synthesized in the host plants are transferred to the fungus to sustain mycorrhizal colonization. The transfer is dependent on RAM2 (REQUIRED FOR ARBUSCULAR MYCORRHIZATION 2) and the ATP binding cassette transporter-mediated plant lipid export pathway. We further show that plant fatty acids can be transferred to the pathogenic fungus and are required for colonization by pathogens. We suggest that the mutualistic mycorrhizal and pathogenic fungi similarly recruit the fatty acid biosynthesis program to facilitate host invasion.

Feed Your Friends: Do Plant Exudates Shape the Root Microbiome?

“…Nucleotides are imported by secondary active transporters, but their exudation remains elusive (Table 1 transporters were proposed to mediate cellular export [97,98]. Peptide uptake is transporter mediated in heterologous systems, and a role of ABC transporters in peptide exudation has been suggested (Table 1) (Table 1), but the mode of lipid exudation into the rhizosphere has yet to be discovered.…”

The plasma membrane proteome of Medicago truncatula roots as modified by arbuscular mycorrhizal symbiosis

“…It is noteworthy that Medtr4g097510 is one of the 12 lipid biosynthetic genes only expressed in AM symbiotic hosts (Bravo et al 2016). This suggests that, similarly to the thioesterase FatM, the ketoacyl-acyl carrier reductase KAR, and the ketoacyl-ACP synthase KAS II (Bravo et al 2017;Jiang et al 2017), the PMassociated enoyl-(acyl carrier) reductase may contribute to supply FAs to the AM symbiont which cannot synthetize C16:0 FAs Tang et al 2016). In support of this idea, the beta-hydroxyacyl-(acyl-carrier-protein) dehydratase FabZ (Medtr4g094265) that leads to the synthesis of palmitate (C16:0) was only detected in the PM fraction of AM roots (Table S1).…”

Trade-Offs in Arbuscular Mycorrhizal Symbiosis: Disease Resistance, Growth Responses and Perspectives for Crop Breeding

“…V.P. Heluta [91], Phytophthora palmivora E.J. Butler [35] and Aphanomyces euteiches Drechsler [92] Salicylic acid production [87,93] Systemic acquired resistance [80,90,[94][95][96][97] Production of other defence compounds, e.g., phenolics [98], β-1,3-glucanase [96,97] and chitinolytic enzymes [99] 2.…”