Agriculture Reference
In-Depth Information
Chapter 3
Q
UORUM
-S
ENSING
L
ANGUAGE IN
B
ACTERIA AND ITS
R
ELEVANCE IN THEIR
I
NTERACTIONS WITH
P
LANTS
B. Rodelas,
1,2
, R. Vílchez
2,3
, L. Mora
1
, A. Lemme
3
, C. Pozo
1,2
,
M. Molina-Muñoz
2
, M.V. Martínez-Toledo
1,2
and J. González-López
1,2,*
1
Departamento de Microbiología, Universidad de Granada, Spain;
2
Instituto del Agua, Universidad de Granada, Spain;
3
Department of Cell and Immune Biology, Helmholtz Center
for Infection Research (HZI), Braunschweig, Germany
A
BSTRACT
The concept of bacteria living as single isolated cells has been replaced by the vision
of these organisms as members of communities that mostly work coordinately, with the
aid of communication systems of variable complexity that make possible for every single
cell to perceive the rest of bacteria sharing an habitat and talk to them. The languages of
bacteria rely on chemical signals, synthesized by the cells and sent out to the surrounding
media, where their concentration rises correlated to the increase of cell numbers. When a
certain threshold cell density (quorum) is reached, the accumulated chemical signals
trigger a coordinated population response, often moved by the need of adaptation to a
change in the environment. The term "quorum sensing" was coined to describe this
ability of bacteria to monitor the size of their populations before taking the decision of
expressing a certain genotype. There are many different molecules released as signals by
bacteria, being the best characterized to date acyl-homoserine lactones (AHLs),
autoinducing oligopeptides (AIPs), and autoinducer 2 (AI-2). Amongst the known
phenotypes regulated by quorum sensing, there are a number of functions related to both
beneficial and pathogenic interactions between bacteria and eukaryotic organisms.
Bacteria that interact with plants are not an exception, and use sophisticated quorum
sensing systems whose involvement on the regulation of important steps for survival and
competition in the rhizosphere, root colonization, and establishment of symbiotic or
*
Corresponding author (jgl@ugr.es).
