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Fatty acid synthesis and lipid metabolism in the obligate biotrophic fungus R hizophagus irregularis during mycorrhization of L otus japonicus
Author(s) -
Wewer Vera,
Brands Mathias,
Dörmann Peter
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12566
Subject(s) - rhizophagus irregularis , biology , biochemistry , galactolipids , lipidome , diacylglycerol kinase , symbiosis , sterol , fatty acid , membrane lipids , oxylipin , lipid metabolism , botany , enzyme , bacteria , gene , protein kinase c , chloroplast , genetics , membrane , arbuscular mycorrhizal , cholesterol
Summary Arbuscular mycorrhiza formation with fungi of the Glomeromycota represents a widespread symbiotic interaction of vascular plants. Different signaling events and metabolic adaptations are required for the close interaction between the two partners. Membrane lipid synthesis is a prerequisite for symbiosis, and membrane properties depend on lipid composition. Lipid profiling was performed by liquid chromatography mass spectrometry to study the role of triacylglycerol, diacylglycerol, phospholipids, galactolipids, sterols and sphingolipids during the colonization of L otus japonicus roots with R hizophagus irregularis (syn. G lomus intraradices ). Mycorrhization leads to an increased phosphate supply and suppresses the increase in galactolipids commonly observed in phosphate‐deprived plants. In addition to free sterols and sterol esters, R. irregularis contains sterol glucosides and acylated sterol glucosides. Glycosylated sphingolipids (glucosylceramide, dihexosylceramide) and inositolphosphorylceramide were detected in the fungus. Lyso‐phosphatidylcholine, a lipid previously implicated in mycorrhiza signaling, is present in low amounts in mock‐infected and mycorrhized roots. The composition of fungal phospholipids changes after mycorrhization because molecular species with palmitvaccenic (di‐16:1) or tetracosenoic (24:1) acyl groups decrease in intraradical mycelium. This adaptation of lipid metabolism during intraradical growth is likely a prerequisite for symbiosis, achieving functional compatibility between the fungal and the periarbuscular membrane. Data mining in genomic and transcript databases revealed the presence of genes encoding enzymes of lipid biosynthesis in R. irregularis . However, no gene encoding multidomain fatty acid de novo synthase was detected in the genome sequence of this obligate biotrophic fungus.