Rhizodeposition shapes rhizosphere microbial community structure in organic soil.
The aims of the study were to determine group specificity in microbial utilization of root-exudate compounds and whole rhizodeposition; quantify the proportions of carbon acquired by microbial groups from soil organic matter and rhizodeposition, respectively; and assess the importance of root-derived C as a driver of soil microbial community structure. Additions of 13C-labelled root-exudate compounds to organic soil and steady-state labelling of Lolium perenne, coupled to compound-specific isotope ratio mass spectrometry, were used to quantify group-specific microbial utilization of rhizodeposition. Microbial utilization of glucose and fumaric acid was widespread through the microbial community, but glycine was utilized by a narrower range of populations, as indicated by the enrichment of phospholipid fatty acid (PLFA) analysis fractions. In L. perenne rhizospheres, high rates of rhizodeposit utilization by microbial groups showed good correspondence with increased abundance of these groups in the rhizosphere. Although rhizodeposition was not the quantitatively dominant C source for microbes in L. perenne rhizospheres, relative utilization of this C source was an important driver of microbial group abundance in organic soil.
Paterson
Eric
E
Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland, UK.
Gebbing
Thomas
T
Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland, UK.
Abel
Claire
C
Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland, UK.
Sim
Allan
A
Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland, UK.
Telfer
Gillian
G
Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland, UK.
D018533:Biomass; D002247:Carbon Isotopes; D005227:Fatty Acids / Q000378:metabolism; D005308:Fertilizers; D008129:Lolium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology; D009584:Nitrogen / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism; D053147:Plant Exudates / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000382:microbiology*; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D025341:Principal Component Analysis; D012988:Soil Microbiology
D002247:Carbon Isotopes; D005227:Fatty Acids; D005308:Fertilizers; D010743:Phospholipids; D053147:Plant Exudates; D009584:Nitrogen