Pharmacological evidence indicates that MAPKK/CDPK modulate NO levels in darkness-induced stomatal closure of broad bean

2008 ◽  
Vol 56 (4) ◽  
pp. 347 ◽  
Author(s):  
Xiaoping She ◽  
Xigui Song

By using pharmacological approaches and laser scanning confocal microscopy (LSCM) based on 4, 5-diaminofluorescein diacetate (DAF-2 DA), the roles of MAPKK/CDPK and their effects on nitric oxide (NO) levels of guard cells during darkness-induced stomatal closure in broad bean were investigated. The results indicated that both 2′-amino-3′-methoxyflavone (PD98059) (an inhibitor of mitogen-activated protein kinase kinase, MAPKK) and trifluoperazine (TFP) (a specific inhibitor of calcium-dependent protein kinase, CDPK) reduced the levels of NO in guard cells and significantly reversed darkness-induced stomatal closure, implying that MAPKK/CDPK mediate darkness-induced stomatal closure by enhancing NO levels in guard cells. In addition, as with NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), but not with nitric oxide synthase inhibitor NG-nitro-L-Arg-methyl ester (L-NAME), PD98059 and TFP not only reduced 4,5-diaminofluorescein diacetate (DAF-2 DA) fluorescence in guard cells by sodium nitroprusside (SNP) in light, but also abolished NO that had been generated during a dark period, and reversed stomatal closure by SNP and by darkness, suggesting MAPKK and CDPK are probably related to restraining the NO scavenging to elevate NO levels in guard cells, during darkness-induced stomatal closure. The results also showed that both PD98059 and TFP reduced stomatal closure by SNP, implying that the possibility of MAPKK and CDPK acting as the target downstream of NO should not be ruled out. There may be a causal and interdependent relationship between MAPKK/CDPK and NO in darkness-induced stomatal closure, and in the process this cross-talk may lead to the formation of a self-amplification loop about them.

2010 ◽  
Vol 58 (2) ◽  
pp. 81 ◽  
Author(s):  
Xiao-Ping She ◽  
Jin Li ◽  
Ai-Xia Huang ◽  
Xi-Zhu Han

By using pharmacological approaches and laser scanning confocal microscopy based on 4,5-diaminofluorescein diacetate (DAF-2DA), the relationship between the inhibition of dark-induced stomatal closure caused by fusicoccin (FC) and the changes of nitric oxide (NO) levels in guard cells in broad bean was studied. The results show that, like 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO), a NO scavenger and NG-nitro-L-Arg-methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS), FC inhibited stomatal closure induced by darkness, and reduced the levels of NO in guard cells in darkness, indicating that FC inhibits dark-induced stomatal closure through lessening NO levels in guard cells. In addition, similar to c-PTIO, both FC and butyric acid not only suppressed sodium nitroprusside (SNP)-induced stomatal closure and DAF-2DA fluorescence in guard cells, but also reopened the closed stomata induced by dark and removed NO that had been generated by dark. The results show that both FC and butyric acid cause NO removal in guard cells, and also suggest that FC-caused NO removal is probably associated with cytosolic acidification in guard cells. Taken together, our results show that FC perhaps causes cytosolic acidification in guard cells, consequently induces NO removal and reduces NO levels in guard cells, and finally inhibits stomatal closure induced by dark.


2005 ◽  
Vol 32 (3) ◽  
pp. 237 ◽  
Author(s):  
Jun-Min He ◽  
Hua Xu ◽  
Xiao-Ping She ◽  
Xi-Gui Song ◽  
Wen-Ming Zhao

Previous studies have showed that UV-B can stimulate closure as well as opening of stomata. However, the mechanism of this complex effect of UV-B is not clear. The purpose of this paper is to investigate the role and the interrelationship of H2O2 and NO in UV-B-induced stomatal closure in broad bean (Vicia faba L.). By epidermal strip bioassay and laser-scanning confocal microscopy, we observed that UV-B-induced stomatal closure could be largely prevented not only by NO scavenger c-PTIO or NO synthase (NOS) inhibitor l-NAME, but also by ascorbic acid (ASC, an important reducing substrate for H2O2 removal) or catalase (CAT, the H2O2 scavenger), and that UV-B-induced NO and H2O2 production in guard cells preceded UV-B-induced stomatal closure. These results indicate that UV-B radiation induces stomatal closure by promoting NO and H2O2 production. In addition, c-PTIO, l-NAME, ASC and CAT treatments could effectively inhibit not only UV-B-induced NO production, but also UV-B-induced H2O2 production. Exogenous H2O2-induced NO production and stomatal closure were partly abolished by c-PTIO and l-NAME. Similarly, exogenous NO donor sodium nitroprusside-induced H2O2 production and stomatal closure were also partly reversed by ASC and CAT. These results show a causal and interdependent relationship between NO and H2O2 during UV-B-regulated stomatal movement. Furthermore, the l-NAME data also indicate that the NO in guard cells of Vicia faba is probably produced by a NOS-like enzyme.


2011 ◽  
Vol 38 (4) ◽  
pp. 303
Author(s):  
Ai-Xia Huang ◽  
Xiao-Ping She

Changes in osmotic pressure can induce stomatal closure to reduce transpirational water loss from plants. In the present work, we investigated the mechanism underlying the perception and transduction of extracellular changes in osmotic pressure in Vicia faba L. guard cells. Using an epidermal strip bioassay and laser-scanning confocal microscopy, we provide evidence that hyperosmotic stress treatment led to stomatal closure and the rapid promotion of hydrogen peroxide (H2O2) production in V. faba guard cells. The effects were largely reduced by H2O2 scavengers ASA, CAT, NADPH oxidase inhibitor DPI and cell wall peroxidase inhibitor SHAM. These results indicate that hyperosmotic stress induces stomatal closure by promoting H2O2 production. Cytochalasin B (CB), latrunculin B (Lat B) and jasplakinolide (JK) inhibited stomatal closure induced by hyperosmotic stress but didn’t prevent the increase of endogenous H2O2 levels, suggesting that microfilaments reorganisation participates in stomatal closure induced by hyperosmotic stress, and may act downstream of H2O2 signalling processes. In addition, we observed splitting of big vacuoles into many small vacuoles in response to hyperosmotic stress and H2O2 treatment, and CB inhibited these changes of vacuoles; stomatal closure was also inhibited. Taken together these results indicate that the stomatal closure in response to hyperosmotic stress may initiate H2O2 generation, and that reorganisation of microfilaments and the changing of vacuoles occurs downstream of H2O2 signalling processes.


2014 ◽  
Vol 41 (8) ◽  
pp. 803 ◽  
Author(s):  
Xiao-Min Ge ◽  
Yan Zhu ◽  
Jun-Min He

The role and the interrelationship of cytosolic alkalisation and nitric oxide (NO) in UVB-induced stomatal closure were investigated in Arabidopsis thaliana (L.) Heynh. by stomatal bioassay and laser-scanning confocal microscopy. In response to 0.5 W m–2 UVB radiation, the rise of NO levels in guard cells occurred after cytosolic alkalisation but preceded stomatal closure. UVB-induced NO production and stomatal closure were both inhibited by NO scavengers, nitrate reductase (NR) inhibitors and a Nia2–5/Nia1–2 mutation, and also by butyrate. Methylamine induced NO generation and stomatal closure in the wild-type but not in the Nia2–5/Nia1–2 mutant or wild-type plants pretreated with NO scavengers or NR inhibitors while enhancing the cytosolic pH in guard cells under light. NO generation in wild-type guard cells was largely induced after 60 min of UVB radiation. The defect in UVB-induced NO generation in Nia2–5/Nia1–2 guard cells did not affect the changes of guard cell pH before 60 min of UVB radiation, but prevented the UVB-induced cytosolic alkalisation after 60 min of radiation. Meanwhile, exogenous NO caused a marked rise of cytosolic pH in guard cells. Together, our results show that cytosolic alkalisation and NR-dependent NO production coordinately function in UVB signalling in A. thaliana guard cells.


2009 ◽  
Vol 57 (6) ◽  
pp. 486 ◽  
Author(s):  
Yuanhua Zhang ◽  
Xiaoping She ◽  
Guangbin Zhang

Role and interrelationship of protein tyrosine phosphatases (PTPases) and H2O2 in light/dark-regulated stomatal movement in Vicia faba were investigated by epidermal strip bioassay, laser-scanning confocal microscopy and assays of PTPase activity. Our results indicate that phenylarsine oxide (PAO), a specific inhibitor of PTPases, ascorbic acid (ASA), an important reducing substrate for H2O2 removal, and catalase (CAT), one of the H2O2 scavenging enzymes, did not cause any change of stomatal aperture in light, but remarkably prevented dark-induced stomatal closure. Exogenous H2O2 had no obvious effect on stomatal aperture in the dark, but significantly induced stomatal closure in light. Both PTPase activity in epidermal strips and endogenous H2O2 level in guard cells in the dark were higher than those in light. The results showed that both PTPases and H2O2 mediate light/dark-regulated stomatal movement, that dark-induced stomatal closure requires the activation of PTPases and the enhancement of H2O2 levels in guard cells, and stomatal opening caused by light is associated with the inactivation of PTPases and the reduction of H2O2 levels in guard cells. Additionally, like ASA and CAT, PAO abolished dark-, exogenous H2O2-induced stomatal closure and dichlorofluorescein fluorescence in guard cells, indicating that activation of PTPases can enhance H2O2 levels probably via suppressing the decrease of H2O2 levels in guard cells. On the other hand, similar to PAO, ASA and CAT evidently prevented dark-, exogenous H2O2-induced stomatal closure and obviously inactivated PTPases in the dark. However, exogenous H2O2 significantly activated PTPases in light. The results show that H2O2 can induce activation of PTPases. Taken together, the present results provide evidence that both H2O2 and PTPases are involved in light/dark-regulated stomatal movement, and the interaction between H2O2 and PTPases plays a pivotal role in light/dark signal transduction process in guard cells.


2005 ◽  
Vol 289 (4) ◽  
pp. E643-E649 ◽  
Author(s):  
Shinya Yamaguchi ◽  
Hiroshi Katahira ◽  
Sachihiko Ozawa ◽  
Yoko Nakamichi ◽  
Toshiaki Tanaka ◽  
...  

To determine whether the increase in glucose uptake following AMP-activated protein kinase (AMPK) activation in adipocytes is mediated by accelerated GLUT4 translocation into plasma membrane, we constructed a chimera between GLUT4 and enhanced green fluorescent protein (GLUT4-eGFP) and transferred its cDNA into the nucleus of 3T3-L1 adipocytes. Then, the dynamics of GLUT4-eGFP translocation were visualized in living cells by means of laser scanning confocal microscopy. It was revealed that the stimulation with 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) and 2,4-dinitrophenol (DNP), known activators of AMPK, promptly accelerates its translocation within 4 min, as was found in the case of insulin stimulation. The insulin-induced GLUT4 translocation was markedly inhibited after addition of wortmannin ( P < 0.01). However, the GLUT4 translocation through AMPK activators AICAR and DNP was not affected by wortmannin. Insulin- and AMPK-activated translocation of GLUT4 was not inhibited by SB-203580, an inhibitor of p38 mitogen-activated protein kinase (MAPK). Glucose uptake was significantly increased after addition of AMPK activators AICAR and DNP ( P < 0.05). AMPK- and insulin-stimulated glucose uptake were similarly suppressed by wortmannin ( P < 0.05–0.01). In addition, SB-203580 also significantly prevented the enhancement of glucose uptake induced by AMPK and insulin ( P < 0.05). These results suggest that AMPK-activated GLUT4 translocation in 3T3-L1 adipocytes is mediated through the insulin-signaling pathway distal to the site of activated phosphatidylinositol 3-kinase or through a signaling system distinct from that activated by insulin. On the other hand, the increase of glucose uptake dependent on AMPK activators AICAR and DNP would be additionally due to enhancement of the intrinsic activity in translocated GLUT4 protein, possibly through a p38 MAPK-dependent mechanism.


2011 ◽  
Vol 38 (4) ◽  
pp. 293 ◽  
Author(s):  
Jun-Min He ◽  
Zhan Zhang ◽  
Rui-Bin Wang ◽  
Yi-Ping Chen

The role of ethylene and the relationship between ethylene and nitric oxide (NO) in ultraviolet B (UV-B)-induced stomatal closure were investigated in Vicia faba L. (broad bean) plants by epidermal strip bioassay, laser-scanning confocal microscopy and assay of ethylene production. In response to UV-B radiation, the rise of NO level in guard cells was after ethylene evolution peak, but preceded stomatal closure. Both UV-B-induced NO generation in guard cells and subsequent stomatal closure were substantially inhibited not only by NO scavenger and nitrate reductase (NR) inhibitors, but also by interfering with ethylene synthesis or perception. Although exogenous NO could reverse the inhibitive effect of interfering with ethylene synthesis or perception on UV-B-induced stomatal closure, the inhibitive effect of NO scavenger and NR inhibitors on UV-B-induced stomatal closure could not be rescued by exogenous ethylene. Taken together, our results clearly show that ethylene participates in the UV-B-induced stomatal closure and acts upstream of the NR source of NO generation in V. faba.


2016 ◽  
Vol 173 (1) ◽  
pp. 760-770 ◽  
Author(s):  
Feng-Chen Li ◽  
Jing Wang ◽  
Mi-Mi Wu ◽  
Cai-Ming Fan ◽  
Xuan Li ◽  
...  

2014 ◽  
Vol 112 (2) ◽  
pp. 613-618 ◽  
Author(s):  
Pengcheng Wang ◽  
Yanyan Du ◽  
Yueh-Ju Hou ◽  
Yang Zhao ◽  
Chuan-Chih Hsu ◽  
...  

The phytohormone abscisic acid (ABA) plays important roles in plant development and adaptation to environmental stress. ABA induces the production of nitric oxide (NO) in guard cells, but how NO regulates ABA signaling is not understood. Here, we show that NO negatively regulates ABA signaling in guard cells by inhibiting open stomata 1 (OST1)/sucrose nonfermenting 1 (SNF1)-related protein kinase 2.6 (SnRK2.6) through S-nitrosylation. We found that SnRK2.6 is S-nitrosylated at cysteine 137, a residue adjacent to the kinase catalytic site. Dysfunction in the S-nitrosoglutathione (GSNO) reductase (GSNOR) gene in the gsnor1-3 mutant causes NO overaccumulation in guard cells, constitutive S-nitrosylation of SnRK2.6, and impairment of ABA-induced stomatal closure. Introduction of the Cys137 to Ser mutated SnRK2.6 into the gsnor1-3/ost1-3 double-mutant partially suppressed the effect of gsnor1-3 on ABA-induced stomatal closure. A cysteine residue corresponding to Cys137 of SnRK2.6 is present in several yeast and human protein kinases and can be S-nitrosylated, suggesting that the S-nitrosylation may be an evolutionarily conserved mechanism for protein kinase regulation.


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