Mycorrhizal phosphate uptake pathway in tomato is phosphorus-repressible and transcriptionally regulated

• Published in: The New phytologist Vol. 181; no. 4; pp. 950 - 959
• Main Authors: Nagy, Réka, Drissner, David, Amrhein, Nikolaus, Jakobsen, Iver, Bucher, Marcel
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.03.2009; Blackwell Publishing; Blackwell Publishing Ltd
• Subjects: Biological Transport; Gene expression; gene regulation; Lycopersicon esculentum; Lycopersicon esculentum - metabolism; Lycopersicon esculentum - microbiology; lysophosphatidylcholine; Lysophosphatidylcholines - metabolism; Microbial colonization; mycorrhiza; mycorrhizae; Mycorrhizae - metabolism; Mycorrhizas; phosphate starvation response; Phosphate transport proteins; Phosphate Transport Proteins - genetics; Phosphate Transport Proteins - physiology; phosphate transporter; phosphate uptake pathways; Phosphates; Phosphates - metabolism; Phosphorus; Phosphorus - metabolism; Plant Proteins - genetics; Plant Proteins - physiology; Plant roots; Plants; Signal Transduction - genetics; Soil fungi; Solanum; Symbiosis; tomato (Solanum lycopersicum) Micro-Tom
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2008.02721.x

Plants colonized by arbuscular mycorrhizal (AM) fungi take up phosphate (Pi) via the mycorrhizal and the direct Pi uptake pathway. Our understanding of the molecular mechanisms involved in the regulation of these pathways is just emerging. Here, we have analyzed the molecular physiology of mycorrhizal Pi uptake in the tomato (Solanum lycopersicum) variety Micro-Tom and integrated the data obtained with studies on chemical signaling in mycorrhiza-inducible Pi transporter gene regulation. At high plant phosphorus (P) status, the mycorrhizal Pi uptake pathway was almost completely repressed and the mycorrhiza-inducible Pi transporter genes were down-regulated. A high plant P status also suppressed the activation of the mycorrhiza-specific StPT3 promoter fragment by phospholipid extracts containing the mycorrhiza signal lysophosphatidylcholine. Our results suggest that the mycorrhizal Pi uptake pathway is controlled at least partially by the plant host. This control involves components in common with the regulatory mechanism of the Pi starvation response pathway in plants.