Biology Reference
In-Depth Information
Ca
2+
signaling
Protein phosphorylation
NO signaling
SA signaling
ROS
JA signaling
Ethylene signaling
ABA signaling
Fig. 5.3
ROS-triggered immune response signaling pathways
NADPH oxidase-dependent manner but accumulated to a greater extent in the
cytoplasm than in the apoplast. Inhibiting apoplastic H
2
O
2
generation abrogated
both cytoplasmic H
2
O
2
accumulation and plant resistance to bacterial pathogens
(Sang et al.
2012
). These results suggest that the apoplastic H
2
O
2
is translocated to
cytoplasm for participation in the pathogen defense.
5.5
Biphasic ROS Production
Two phases of ROS induction by PAMPs/elicitors have been reported in plant cell
suspension cultures. Very rapid responses (within minutes) have been termed phase
1 (Baker and Orlandi
1995
) and have been shown to be specifi cally inhibited by
DPI, calcium infl ux inhibitors, and kinase inhibitors (Baker and Orlandi
1995
;
Hammond-Kosac and Jones
1996
). The phase I responses are not always correlated
with defense responses. Later ROS production (many hours) is termed phase II and
it appears to take part in defense signaling system (Allan and Fluhr
1997
).
5.6
ROS Plays a Central Role in Triggering Immune
Responses
ROS appears to interact with various defense signaling systems (Fig.
5.3
). It plays a
central role in launching the defense response (Vandenabeele et al.
2003
). ROS
induces Ca
2+
signaling system, reversible phosphorylation system, ubiquitin-
proteasome signaling pathway, NO signaling system, salicylic acid signaling sys-
tem, ethylene-mediated signaling system, and jasmonic acid - dependent signaling
Search WWH ::
Custom Search