CuAO-mediated H2O2 production is involved in ethylene-induced stomatal closure.

 

Involvement of copper amine oxidase (CuAO)-dependent hydrogen peroxide synthesis in ethylene-induced stomatal closure in Vicia faba.

by Song X. G., She X. P., Yue M., Liu Y. E., Wang Y. X., Zhu X., Huang A. X. (2014)

in Russ. J. Plant Physiol. 61, 390–396. – doi: 10.1134/S1021443714020150 –

CrossRef Full Text | Google Scholar – 

https://link.springer.com/article/10.1134%2FS1021443714020150

Abstract

Ethylene promotes stomatal closure via inducing hydrogen peroxide (H₂O₂) generation. H₂O₂ can be catalytically synthesized by several enzymes in plants.

Here, by means of stomatal bioassay, the analysis of enzyme activity and using laser-scanning confocal microscopy based on the H₂O₂-sensitive probe 2′,7′-dichlorodihydrofluorescein diacetate (H₂DCF-DA), the roles of copper amine oxidase (CuAO) in ethylene-induced H₂O₂ production in guard cells and stomatal closure in Vicia faba L. were investigated.

1-aminocyclopropane-1-carboxylic acid (ACC), an immediate precursor of ethylene synthesis, and ethylene gas significantly activated CuAO in intercellular washing fluid from leaves, the production of H₂O₂ in guard cells, and stomatal closure. These effects of ACC and ethylene gas were largely prevented by both aminoguanidine and 2-bromoethylamine, which are irreversible inhibitors of CuAO.

Among major catalyzed and metabolized products of CuAO, only H₂O₂ could markedly promote stomatal closure and evidently reversed the effect of CuAO inhibitor on stomatal closure by ACC and ethylene gas.

The data described above show that CuAO-mediated H₂O₂ production is involved in ethylene-induced stomatal closure.

The relationship between NO and H2O2 during UV-B-regulated stomatal movement.

 

The role and the interrelationship of hydrogen peroxide and nitric oxide in the UV-B-induced stomatal closure in broad bean

by He J., Xu H., She X.-P., Song X.-G., Zhao W.-M. (2005)

in Funct. Plant Biol. 32, 237–247. doi: 10.1071/FP04185 –

CrossRef Full Text | Google Scholar

http://www.publish.csiro.au/?paper=FP04185

Abstract

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 fabaL.).

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.

 

Darkness-induced stomatal closure in broad bean

 

Copper amine oxidase-catalysed hydrogen peroxide involves production of nitric oxide in darkness-induced stomatal closure in broad bean

by Huang A.-X., WangY.-S., She X.-P., Mu J., Jin-Liang Zhao J.-L. (2015)

in Functional Plant Biology – Published online: 30 September 2015

http://dx.doi.org/10.1071/FP15172

Abstract

Hydrogen peroxide is an important intermediate in darkness-induced stomatal closure.

In the present work, we provide evidence that copper amine oxidase (CuAO) was involved in H₂O₂ production in darkness-induced stomatal closure in Vicia faba L. Darkness activated CuAO in intercellular washing fluid from leaves. Aminoguanidine (AG) and 2-bromoethylamine (BEA), which were both irreversible inhibitors of CuAO, significantly suppressed darkness-induced stomatal closure and H₂O₂ generation. The effects of AG and BEA were reversed only by H₂O₂ but not by other products of CuAO.

These results indicate that CuAO participates in darkness-induced stomatal closure through its reaction product, H₂O₂. Furthermore, darkness-induced nitric oxide (NO) production and cytosolic alkalinisation were obviously inhibited by AG and BEA, and only H₂O₂, among the products of CuAO, could reverse the effects, implying that the CuAO-catalysed product H₂O₂ is required for NO production and cytosolic alkalinisation to a large extent in darkness-induced stomatal closure. In addition, butyric acid blocked but methylamine enhanced the ability of H₂O₂ to reverse the effect of BEA on NO production, suggesting that cytosolic alkalinisation is involved in CuAO-mediated NO generation in darkness-induced stomatal closure.