Active root-inhabiting microbes identified by rapid incorporation of plant-derived carbon into RNA

TY - JOUR

T1 - Active root-inhabiting microbes identified by rapid incorporation of plant-derived carbon into RNA

AU - Vandenkoornhuyse, Philippe

AU - Mahe, Stephane

AU - Ineson, Philip

AU - Staddon, Phil

AU - Ostle, Nick

AU - Cliquet, Jean-Bernard

AU - Francez, Andre-Jean

AU - Fitter, Alastair H.

AU - Young, J. Peter W.

PY - 2007/10/23

Y1 - 2007/10/23

N2 - Plant roots harbor a large diversity of microorganisms that have an essential role in ecosystem functioning. To better understand the level of intimacy of root-inhabiting microbes such as arbuscular mycorrhizal fungi and bacteria, we provided (CO2)-C-13 to plants at atmospheric concentration during a 5-h pulse. We expected microbes dependent on a carbon flux from their host plant to become rapidly labeled. We showed that a wide variety of microbes occurred in roots, mostly previously unknown. Strikingly, the greatest part of this unsuspected diversity corresponded to active primary consumers. We found 17 bacterial phylotypes co-occurring within roots of a single plant, including five potentially new phylotypes. Fourteen phylotypes were heavily labeled with the C-13. Eight were phylogenetically close to Burkholderiales, which encompass known symbionts; the others were potentially new bacterial root symbionts. By analyzing unlabeled and C-13-enriched RNAs, we demonstrated differential activity in C consumption among these root-inhabiting microbes. Arbuscular mycorrhizal fungal RNAs were heavily labeled, confirming the high carbon flux from the plant to the fungal compartment, but some of the fungi present appeared to be much more active than others. The results presented here reveal the possibility of uncharacterized root symbioses.

AB - Plant roots harbor a large diversity of microorganisms that have an essential role in ecosystem functioning. To better understand the level of intimacy of root-inhabiting microbes such as arbuscular mycorrhizal fungi and bacteria, we provided (CO2)-C-13 to plants at atmospheric concentration during a 5-h pulse. We expected microbes dependent on a carbon flux from their host plant to become rapidly labeled. We showed that a wide variety of microbes occurred in roots, mostly previously unknown. Strikingly, the greatest part of this unsuspected diversity corresponded to active primary consumers. We found 17 bacterial phylotypes co-occurring within roots of a single plant, including five potentially new phylotypes. Fourteen phylotypes were heavily labeled with the C-13. Eight were phylogenetically close to Burkholderiales, which encompass known symbionts; the others were potentially new bacterial root symbionts. By analyzing unlabeled and C-13-enriched RNAs, we demonstrated differential activity in C consumption among these root-inhabiting microbes. Arbuscular mycorrhizal fungal RNAs were heavily labeled, confirming the high carbon flux from the plant to the fungal compartment, but some of the fungi present appeared to be much more active than others. The results presented here reveal the possibility of uncharacterized root symbioses.

KW - ribosomal RNA

KW - stable isotope probing

KW - symbiosis

KW - arbuscular mycorrhiza

KW - endophytes

KW - ARBUSCULAR MYCORRHIZAL FUNGI

KW - DIVERSITY

KW - SOIL

KW - ASSOCIATION

KW - ECOSYSTEM

KW - BACTERIA

KW - FIELD

KW - DNA

U2 - 10.1073/pnas.0705902104

DO - 10.1073/pnas.0705902104

M3 - Article

SN - 0027-8424

VL - 104

SP - 16970

EP - 16975

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 43

ER -