Effect of P availability on temporal dynamics of carbon allocation and Glomus intraradices high-affinity P transporter gene induction in arbuscular mycorrhiza

Olsson, Pål Axel; Hansson, Maria; Burleigh, Stephen (2006). Effect of P availability on temporal dynamics of carbon allocation and Glomus intraradices high-affinity P transporter gene induction in arbuscular mycorrhiza. Applied and Environmental Microbiology, 72, (6), 4115 - 4120
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DOI:
| Published | English
Authors:
Olsson, Pål Axel ; Hansson, Maria ; Burleigh, Stephen
Department:
Biodiversity
Department of Biology
Microbial Ecology
Plant Biology
Research Group:
Microbial Ecology
Plant Biology
Abstract:
Arbuscular mycorrhizal (AM) fungi depend on a C supply from the plant host and simultaneously provide phosphorus to the colonized plant. We therefore evaluated the influence of external P on C allocation in monoxenic Daucus carota-Glomus intraradices cultures in an AM symbiosis. Fungal hyphae proliferated from a solid minimal medium containing colonized roots into a C-free liquid minimal medium with high or low P availability. Roots and hyphae were harvested periodically, and the flow of C from roots to fungus was measured by isotope labeling. We also measured induction of a G. intraradices high-affinity P transporter to estimate fungal P demand. The prevailing hypothesis is that high P availability reduces mycorrhizal fungal growth, but we found that C How to the fungus was initially highest at the high P level. Only at later harvests, after 100 days of in vitro. culture, were C flow and fungal growth limited at high P availability. Thus, AM fungi can benefit initially from P-enriched environments in terms of plant C allocation. As expected, the P transporter induction was significantly greater at low P availability and greatest in very young mycelia. We found no direct link between C How to the fungus and the P transporter transcription level, which indicates that a good C supply is not essential for induction of the high-affinity P transporter. We describe a mechanism by which P regulates symbiotic C allocation, and we discuss how this mechanism may have evolved in a competitive environment.
ISSN:
0099-2240
LUP-ID:
69d69ae1-b2e9-4400-acf4-1444589b333a | Link: https://lup.lub.lu.se/record/69d69ae1-b2e9-4400-acf4-1444589b333a | Statistics

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