Phosphate Uptake from Phytate Due to Hyphae-Mediated Phytase Activity by Arbuscular Mycorrhizal Maize

• Published in: Frontiers in plant science Vol. 8; p. 684
• Main Authors: Wang, Xin-Xin, Hoffland, Ellis, Feng, Gu, Kuyper, Thomas W.
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 28.04.2017
• Subjects: Acid phosphatase; Maize cultivars; Mycelium; Phytase; Phytate; Plant Science; mycelium; phytase; acid phosphatase; maize cultivars; phytate
• DOI: 10.3389/fpls.2017.00684
• ISSN: 1664-462X

Phytate is the most abundant form of soil organic phosphorus (P). Increased P nutrition of arbuscular mycorrhizal plants derived from phytate has been repeatedly reported. Earlier studies assessed acid phosphatase rather than phytase as an indication of mycorrhizal fungi-mediated phytate use. We investigated the effect of mycorrhizal hyphae-mediated phytase activity on P uptake by maize. Two maize ( L.) cultivars, non-inoculated or inoculated with the arbuscular mycorrhizal fungi or , were grown for 45 days in two-compartment rhizoboxes, containing a root compartment and a hyphal compartment. The soil in the hyphal compartment was supplemented with 20, 100, and 200 mg P kg soil as calcium phytate. We measured activity of phytase and acid phosphatase in the hyphal compartment, hyphal length density, P uptake, and plant biomass. Our results showed: (1) phytate addition increased phytase and acid phosphatase activity, and resulted in larger P uptake and plant biomass; (2) increases in P uptake and biomass were correlated with phytase activity but not with acid phosphatase activity; (3) lower phytate addition rate increased, but higher addition rate decreased hyphal length density. We conclude that P from phytate can be taken up by arbuscular mycorrhizal plants and that phytase plays a more important role in mineralizing phytate than acid phosphatase.