2024-03-29T08:06:33Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/33942021-12-28T15:50:01Zcom_10261_59com_10261_6col_10261_312
00925njm 22002777a 4500
dc
Matilla, Miguel A.
author
Espinosa-Urgel, Manuel
author
Rodríguez-Herva, José J.
author
Ramos, Juan L.
author
Ramos-González, María Isabel
author
2007-09-04
[Background] Mutualistic interactions less well known than those between rhizobia and legumes
are commonly found between plants and bacteria, frequently pseudomonads, which colonize roots
and adjacent soil areas (the rhizosphere).
[Results] A global analysis of Pseudomonas putida genes expressed during their interaction with
maize roots revealed how a bacterial population adjusts its genetic program to this lifestyle.
Differentially expressed genes were identified by comparing rhizosphere-colonizing populations
with three distinct controls covering a variety of nutrients, growth phases and life styles (planktonic
and sessile). Ninety rhizosphere up-regulated (rup) genes, which were induced relative to all three
controls, were identified, whereas there was no repressed gene in common between the
experiments. Genes involved in amino acid uptake and metabolism of aromatic compounds were
preferentially expressed in the rhizosphere, which reflects the availability of particular nutrients in
root exudates. The induction of efflux pumps and enzymes for glutathione metabolism indicates
that adaptation to adverse conditions and stress (oxidative) response are crucial for bacterial life
in this environment. The finding of a GGDEF/EAL domain response regulator among the induced
genes suggests a role for the turnover of the secondary messenger c-diGMP in root colonization.
Several mutants in rup genes showed reduced fitness in competitive root colonization.
[Conclusion] Our results show the importance of two selective forces of different nature to
colonize the rhizosphere: stress adaptation and availability of particular nutrients. We also identify
new traits conferring bacterial survival in this niche and open a way to the characterization of
specific signalling and regulatory processes governing the plant-Pseudomonas association.
Genome Biology 2007, 8:R179
1465-6914
http://hdl.handle.net/10261/3394
10.1186/gb-2007-8-9-r179
17784941
Genomic analysis reveals the major driving forces of bacterial life in the rhizosphere