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In-Depth Information
pathway and 1-aminocyclopropane-1-carboxylate (ACC) oxidase is the fi nal stage
enzyme involved in conversion of ACC to ethylene. Transcript tags coding for both
the enzymes were up-regulated within 2 h of increase in H
2
O
2
, followed by an
increase in ethylene-responsive proteins, such as EREBP/AP2 domain proteins
(Vandenabeele et al.
2003
).
Ethylene receptor ETR1 (for ethylene response 1) can function as an ROS sensor
(Desikan et al.
2005
). The ethylene receptor ETR1 involved in ethylene perception
and signaling has been shown to mediate H
2
O
2
signaling in
Arabidopsis
(Desikan
et al.
2005
). Mutation of a Cys residue in the N-terminal region of ETR1 disrupts
H
2
O
2
signaling in plants (Desikan et al.
2005
). Four ethylene-responsive element-
binding proteins (EREBPs), the ethylene-responsive transcription factor (ERF1), and
a CEO1-like protein, which is a potential cofactor of EREBP transcription factors,
were found to be up-regulated by H
2
O
2
in tobacco (Vandenabeele et al.
2003
).
Ethylene receptor ETR1 has been shown to mediate H
2
O
2
signaling in
Arabidopsis
(Desikan et al.
2005
). ETR1 functions as an ROS sensor. Mutation of a Cys residue in
the N-terminal region of ETR1 disrupts H
2
O
2
signaling in plants (Desikan et al.
2005
).
The transcription factors induced by H
2
O
2
include ethylene-responsive element bind-
ing protein (EREBP) in
Arabidopsis
(Desikan et al.
2001
). H
2
O
2
up- regulates four
ethylene-responsive element-binding proteins (EREBPs), the ethylene-responsive
transcription factor (ERF1), and a CEO1-like protein, which is a potential cofactor of
EREBP transcription factors in tobacco (Vandenabeele et al.
2003
).
5.12
Interplay Between ROS and Jasmonate Signaling
Systems
A very rapid and sustained up-regulation of transcript tags that are involved in the
production of JA signals was observed in ROS-elicited tobacco plants (Vandenabeele
et al.
2003
). Lipoxygenase is a key enzyme in JA biosynthesis. The gene encoding
lipoxygenase (
Lox1
) is induced by ROS (Vranová et al.
2002
). The genes encoding
lipase, lipoxygenase, 12-oxophytodienoate reductase (12-ODPR), and divinyl ether
synthase are activated in tobacco leaves accumulating ROS (Vandenabeele et al.
2003
). These results suggest that ROS is involved in induction of JA biosynthesis.
5.13
Interplay Between ROS and Abscisic Acid (ABA)
Signaling Systems
ABA has been shown to activate ROS signaling system (Hung et al.
2008
; Wang and
Song
2008
; Zhang et al.
2011
). ABA is shown to induce the production of ROS (Pei
et al.
2000
; Zhang et al.
2001
; Sakamoto et al.
2008
). H
2
O
2
is synthesized in response
to exogenous ABA (Guan et al.
2000
; Pei et al.
2000
). NADPH oxidase
AtrbohD
and
AtrbohF
genes function in ROS-dependent ABA signaling in
Arabidopsis
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