Plant growth-promoting bacteria and nitrate availability: impacts on root development and nitrate uptake.
Plant growth-promoting bacteria (PGPB) and NO-3 availability both affect NO-3 uptake and root architecture. The presence of external NO-3 induces the expression of NO-3 transporter genes and elicits lateral root elongation in the part of the root system exposed to the NO-3 supply. By contrast, an increase in NO-3 supply leads to a higher plant N status (low N demand), which represses both the NO-3 transporters and lateral root development. The effects of PGPB on NO-3 uptake and root development are similar to those of low NO-3 availability (concomitant stimulation of NO-3 uptake rate and lateral root development). The mechanisms responsible for the localized and long-distance regulation of NO-3 uptake and root development by NO-3 availability are beginning to be elucidated. By contrast, the signalling and transduction pathways elicited by the rhizobacteria remain totally unknown. This review will compare the effects of NO-3 availability and PGPB on root morphogenesis and NO-3 uptake, in order to determine whether interactions exist between the NO-3-dependent and the PGPB-dependent regulatory pathways.
Mantelin
Sophie
S
Université Montpellier II, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR 113 UM2/IRD/CIRAD/INRA/ENSAM, CC 02, Place E Bataillon, 34095 Montpellier cedex 05, France.
Touraine
Bruno
B
D001419:Bacteria / Q000254:growth & development*; D009566:Nitrates / Q000378:metabolism* / Q000494:pharmacology; D063245:Plant Development; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development* / Q000382:microbiology; D010944:Plants / Q000187:drug effects / Q000382:microbiology; D012988:Soil Microbiology
D009566:Nitrates