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Query: EC:1.7.1.2 (
nitrate reductase
)
3,861
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
We investigated the effects of salt-sensitive signaling molecules on ionic fluxes and gene expression related to K
+
/Na
+
homeostasis in a perennial herb,
Glycyrrhiza uralensis
, during short-term NaCl stress (100 mM, 24 h). Salt treatment caused more pronounced Na
+
accumulation in root cells than in leaf cells. Na
+
ions were mostly compartmentalized in vacuoles. Roots exposed to NaCl showed increased levels of extracellular ATP (eATP), cytosolic Ca
2+
, H
2
O
2
, and NO. Steady-state flux recordings revealed that these salt-sensitive signaling molecules enhanced NaCl-responsive Na
+
efflux, due to the activated Na
+
/H
+
antiport system in the plasma membrane (PM). Moreover, salt-elicited K
+
efflux, which was mediated by depolarization-activated cation channels, was reduced with the addition of Ca
2+
, H
2
O
2
, NO, and eATP. The salt-adaptive effects of these molecules (Na
+
extrusion and K
+
maintenance) were reduced by pharmacological agents, including LaCl
3
(a PM Ca
2+
channel inhibitor), DMTU (a reactive oxygen species scavenger), cPTIO (an NO scavenger), or
PPADS
(an antagonist of animal PM purine P2 receptors). RT-qPCR data showed that the activation of the PM Na
+
/H
+
antiport system in salinized roots most likely resulted from the upregulation of two genes,
GuSOS1
and
GuAHA
, which encoded the PM Na
+
/H
+
antiporter, salt overly sensitive 1 (SOS1), and H
+
-ATPase, respectively. Clear interactions occurred between these salt-sensitive agonists to accelerate transcription of salt-responsive signaling pathway genes in
G. uralensis
roots. For example, Ca
2+
, H
2
O
2
, NO, and eATP promoted transcription of
GuSOS3
(salt overly sensitive 3) and/or
GuCIPK
(CBL-interacting protein kinase) to activate the predominant Ca
2+
-SOS signaling pathway in salinized liquorice roots. eATP, a novel player in the salt response of
G. uralensis
, increased the transcription of
GuSOS3, GuCIPK
,
GuRbohD
(respiratory burst oxidase homolog protein D),
GuNIR
(
nitrate reductase
),
GuMAPK3
, and
GuMAPK6
(the mitogen-activated protein kinases 3 and 6). Moreover,
GuMAPK3
and
GuMAPK6
expression levels were enhanced by H
2
O
2
in NaCl-stressed
G. uralensis
roots. Our results indicated that eATP triggered downstream components and interacted with Ca
2+
, H
2
O
2
, and NO signaling to maintain K
+
/Na
+
homeostasis. We propose that a multiple signaling network regulated K
+
/Na
+
homeostasis in NaCl-stressed
G. uralensis
roots.
...
PMID:Salt-Sensitive Signaling Networks in the Mediation of K
+
/Na
+
Homeostasis Gene Expression in
Glycyrrhiza uralensis
Roots. 2885 12
