Differentiation of polyphosphate metabolism between the extra- and intraradical hyphae of arbuscular mycorrhizal fungi
Article first published online: 4 JAN 2002
Volume 149, Issue 3, pages 555–563, March 2001
How to Cite
Tatsuhiro, E., Sally E., S. and F., A. S. (2001), Differentiation of polyphosphate metabolism between the extra- and intraradical hyphae of arbuscular mycorrhizal fungi. New Phytologist, 149: 555–563. doi: 10.1046/j.1469-8137.2001.00040.x
- Issue published online: 4 JAN 2002
- Article first published online: 4 JAN 2002
- Received: 5 June 2000 Accepted: 26 September 2000
- acid phosphatase;
- arbuscular mycorrhizal fungi;
- Neutral red;
- acidic vacuole
• Regulation of polyphosphate metabolism is reported in arbuscular mycorrhizal symbiosis.
• Marigold (Tagetes patula) plants inoculated with Glomus coronatum or Glomus etunicatum were grown in mesh bags. Exopolyphosphatase activity in extra- and intraradical hyphae was measured and characterized. The hyphae were stained with Neutral red to show acidic vacuoles in which polyphosphate synthesis might occur.
• Exopolyphosphate activity was differently expressed between the extra- and intraradical hyphae, as indicated by different pH optima; high activity was observed at pH 5.0 in the intraradical hyphae of both fungal species. Km values were lower at neutral pH with long-chain polyphosphate, whereas acidic activity showed lower Km with short-chain polyphosphate. Both extra- and intradical hyphae had acidic vacuoles. Polyphosphate occurred in the hyphae of the high-P, but not the low-P treatment. By contrast, exopolyphosphatase activity and vacuolar acidity were relatively constant irrespective of polyphosphate status.
• The fungi have at least two different exopolyphosphatase-type enzymes which are differently expressed between extra- and intraradical hyphae; polyphosphate accumulation might be a dynamic balance between synthesis and hydrolysis.