Lipoxygenase 2 functions in exogenous nitric oxide-induced stomatal closure in Arabidopsis thaliana

2015 ◽  
Vol 42 (11) ◽  
pp. 1019 ◽  
Author(s):  
Yanfeng Sun ◽  
Dong Lv ◽  
Wei Wang ◽  
Wei Xu ◽  
Li Wang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Arabidopsis Thaliana ◽  
Potassium Channels ◽  
Stomatal Closure ◽  
Normal Growth ◽  
Guard Cells ◽  
Growth Conditions ◽  
Mesophyll Cells ◽  
No Donor ◽  
Leaf Water Loss

Nitric oxide (NO) and lipoxygenase (LOX)-derived oxylipins play important roles in stomatal closure in plants, and LOX–NO crosstalk has been indicated in mesophyll cells. However, whether the crosstalk also exists in guard cells is not clear and the detailed mechanisms remain unknown. Here, we report that exogenous sodium nitroprusside (SNP, a NO donor)-induced stomatal closure was clearly impaired in the AtLOX2 null mutant lox2–1 compared with wild-type (WT) Arabidopsis thaliana (L.) Heynh. Patch clamp analysis showed that the SNP-suppressed activity of inward-rectifying potassium channels in lox2–1 guard cell protoplasts was reduced. Moreover, SNP promoted an increase in cytosolic Ca2+ concentration in guard cells of lox2–1 mutants was inhibited compared with the WT. These results suggest that AtLOX2 plays an important role in NO-induced stomatal closure by affecting the cytosolic Ca2+ concentration increase and the activity of inward-rectifying potassium channels in guard cells. Furthermore, lox2–1 mutants showed a higher rate of leaf water loss and a relatively wider stomatal aperture than the WT under normal growth conditions. These data imply that AtLOX2 might modulate stomatal movement by increasing oxylipin generation in A. thaliana.

Cytosolic alkalisation and nitric oxide production in UVB-induced stomatal closure in Arabidopsis thaliana

2014 ◽  
Vol 41 (8) ◽  
pp. 803 ◽  
Author(s):  
Xiao-Min Ge ◽  
Yan Zhu ◽  
Jun-Min He
Keyword(s):  
Nitric Oxide ◽  
Arabidopsis Thaliana ◽  
Laser Scanning ◽  
Stomatal Closure ◽  
Guard Cells ◽  
No Production ◽  
Uvb Radiation ◽  
Wild Type ◽  
Cytosolic Ph ◽  
No Scavengers

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.

scholarly journals Evolutionary History and Activity of RNase H1-Like Proteins in Arabidopsis thaliana

2020 ◽  
Vol 61 (6) ◽  
pp. 1107-1119
Author(s):  
Jan Kuciński ◽  
Sebastian Chamera ◽  
Aleksandra Kmera ◽  
M Jordan Rowley ◽  
Sho Fujii ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Embryonic Development ◽  
Evolutionary History ◽  
Common Ancestor ◽  
Normal Growth ◽  
Plastid Dna ◽  
Growth Conditions ◽  
Replicative Stress ◽  
The Common ◽  
Rna:Dna Hybrids

Abstract RNase H1 is an endonuclease specific toward the RNA strand of RNA:DNA hybrids. Members of this protein family are present in most living organisms and are essential for removing RNA that base pairs with DNA. It prevents detrimental effects of RNA:DNA hybrids and is involved in several biological processes. Arabidopsis thaliana has been previously shown to contain three genes encoding RNase H1 proteins that localize to three distinct cellular compartments. We show that these genes originate from two gene duplication events. One occurred in the common ancestor of dicots and produced nuclear and organellar RNase H1 paralogs. Second duplication occurred in the common ancestor of Brassicaceae and produced mitochondrial- and plastid-localized proteins. These proteins have the canonical RNase H1 activity, which requires at least four ribonucleotides for endonucleolytic digestion. Analysis of mutants in the RNase H1 genes revealed that the nuclear RNH1A and mitochondrial RNH1B are dispensable for development under normal growth conditions. However, the presence of at least one organellar RNase H1 (RNH1B or RNH1C) is required for embryonic development. The plastid-localized RNH1C affects plastid DNA copy number and sensitivity to replicative stress. Our results present the evolutionary history of RNH1 proteins in A. thaliana, demonstrate their canonical RNase H1 activity and indicate their role in early embryonic development.

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

2005 ◽  
Vol 32 (3) ◽  
pp. 237 ◽  
Author(s):  
Jun-Min He ◽  
Hua Xu ◽  
Xiao-Ping She ◽  
Xi-Gui Song ◽  
Wen-Ming Zhao
Keyword(s):  
Vicia Faba ◽  
Laser Scanning ◽  
Broad Bean ◽  
Stomatal Closure ◽  
Guard Cells ◽  
Laser Scanning Confocal Microscopy ◽  
H2o2 Production ◽  
No Production ◽  
No Donor ◽  
Scanning Confocal Microscopy

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.

Cytosolic phosphofructokinases are important for sugar homeostasis in leaves of Arabidopsis thaliana

2021 ◽  
Author(s):  
Laura Kathrine Perby ◽  
Simon Richter ◽  
Konrad Weber ◽  
Alina Johanna Hieber ◽  
Natalia Hess ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Double Mutant ◽  
Normal Growth ◽  
Growth Conditions ◽  
Metabolic Phenotype ◽  
Minor Role ◽  
Knock Out ◽  
Genes Encoding ◽  
Fructose 1,6 Bisphosphate ◽  
Sugar Homeostasis

Abstract Background and Aims ATP-dependent phosphofructokinases (PFKs) catalyse phosphorylation of the carbon-1 position of fructose-6-phosphate, to form fructose-1,6-bisphosphate. In the cytosol, this is considered a key step in channelling carbon into glycolysis. Arabidopsis thaliana has seven genes encoding PFK isoforms, two chloroplastic and five cytosolic. This study focusses on the four major cytosolic isoforms of PFK in vegetative tissues of A. thaliana. Methods We have isolated homozygous knock-out individual mutants (pfk1, pfk3, pfk6, pfk7) and two double mutants (pfk1/7 and pfk3/6) and characterized their growth and metabolic phenotypes. Key Results In contrast to single mutants and the double mutant pfk3/6 for the hypoxia-responsive isoforms, the double mutant pfk1/7 had reduced PFK activity and shows a clear visual and metabolic phenotype with reduced shoot growth, early flowering, and elevated hexose levels. This mutant also has an altered ratio of short/long aliphatic glucosinolates and an altered root-shoot distribution. Surprisingly, this mutant does not show any major changes in short-term carbon flux and in levels of hexose-phosphates. Conclusions We conclude that the two isoforms PFK1 and PFK7 are important for sugar homeostasis in leaf metabolism and apparently source/sink relations in Arabidopsis, while PFK3 and PFK6 only play a minor role under normal growth conditions.

Cytosolic alkalization-mediated H2O2 and NO production are involved in darkness-induced stomatal closure in Vicia faba

2013 ◽  
Vol 93 (1) ◽  
pp. 119-130 ◽  
Author(s):  
Yinli Ma ◽  
Xiaoping She ◽  
Shushen Yang
Keyword(s):  
Nitric Oxide ◽  
Vicia Faba ◽  
Butyric Acid ◽  
Stomatal Closure ◽  
Guard Cells ◽  
Weak Acid ◽  
No Production ◽  
Tetraacetic Acid ◽  
Acetoxymethyl Ester ◽  
Cytosolic Ph

Ma, Y., She, X. and Yang, S. 2013. Cytosolic alkalization-mediated H 2 O 2 and NO production are involved in darkness-induced stomatal closure in Vicia faba. Can. J. Plant Sci. 93: 119–130. Darkness raised cytosolic pH, hydrogen peroxide (H2O2) and nitric oxide (NO) levels in guard cells while inducing Vicia faba stomatal closure. These darkness effects were prevented by weak acid butyric acid, H2O2 modulators ascorbic acid (ASA), catalase (CAT), diphenyleneiodonium (DPI) and NO modulators 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO), NG-nitro-L-arg-methyl ester (L-NAME) respectively. The data suggest that cytosolic alkalization, H2O2 and NO all participate in darkness-induced stomatal closure. During darkness treatment, pH rise became noticeable at 10 min and peaked at 25 min, while H2O2 and NO production increased significantly at 20 min and reached their maximums at 40 min. The H2O2 and NO levels were increased by methylamine in light and decreased by butyric acid in darkness. The results show that cytosolic alkalization induces H2O2 and NO production. ASA, CAT and DPI suppressed NO production by methylamine, c-PTIO and L-NAME prevented H2O2 generation by methylamine. Calcium chelator 1,2-bis (2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester (BAPTA-AM) and 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) restricted darkness-induced alkalization, H2O2 and NO production and stomatal closure. We suggest that cytosolic alkalization is necessary for H2O2 and NO production during darkness-induced stomatal closure. H2O2 mediates NO synthesis by alkalization, and vice versa. Calcium may act upstream of cytosolic alkalization, H2O2 and NO production, besides its known action downstream of H2O2 and NO.

scholarly journals Nitric oxide in guard cells as an important secondary messenger during stomatal closure

2013 ◽  
Vol 4 ◽  
Author(s):  
Gunja Gayatri ◽  
Srinivas Agurla ◽  
Agepati S. Raghavendra
Keyword(s):  
Nitric Oxide ◽  
Stomatal Closure ◽  
Guard Cells ◽  
Secondary Messenger

scholarly journals Starch Granules in Arabidopsis thaliana Mesophyll and Guard Cells Show Similar Morphology but Differences in Size and Number

2021 ◽  
Vol 22 (11) ◽  
pp. 5666
Author(s):  
Qingting Liu ◽  
Xiaoping Li ◽  
Joerg Fettke
Keyword(s):  
Arabidopsis Thaliana ◽  
Starch Synthesis ◽  
Guard Cells ◽  
Morphological Properties ◽  
Fast Method ◽  
Starch Granules ◽  
Mesophyll Cells ◽  
Laser Confocal Scanning Microscopy ◽  
Transitory Starch ◽  
Confocal Scanning

Transitory starch granules result from complex carbon turnover and display specific situations during starch synthesis and degradation. The fundamental mechanisms that specify starch granule characteristics, such as granule size, morphology, and the number per chloroplast, are largely unknown. However, transitory starch is found in the various cells of the leaves of Arabidopsis thaliana, but comparative analyses are lacking. Here, we adopted a fast method of laser confocal scanning microscopy to analyze the starch granules in a series of Arabidopsis mutants with altered starch metabolism. This allowed us to separately analyze the starch particles in the mesophyll and in guard cells. In all mutants, the guard cells were always found to contain more but smaller plastidial starch granules than mesophyll cells. The morphological properties of the starch granules, however, were indiscernible or identical in both types of leaf cells.

scholarly journals ABA homeostasis and long-distance translocation is redundantly regulated by ABCG ABA importers

2021 ◽  
Author(s):  
Yuqin Zhang ◽  
Himabindu Vasuki ◽  
Jie Liu ◽  
Hamutal Bar ◽  
Shani Lazary ◽  
...  
Keyword(s):  
Plasma Membranes ◽  
Stomatal Closure ◽  
Normal Growth ◽  
Growth Conditions ◽  
Long Distance ◽  
Leaf Mesophyll ◽  
A Genome ◽  
Use Efficiency ◽  
Growth Development ◽  
Genome Scale

The effects of abscisic acid (ABA) on plant growth, development and response to the environment depend on local ABA concentrations. Here, we exploited a genome-scale amiRNA screen, targeting the Arabidopsis transportome, to show that ABA homeostasis is regulated by two previously unknown ABA transporters. ABCG17 and ABCG18 are localized to the plasma membranes of leaf mesophyll and stem cortex cells to redundantly promote ABA import, leading to conjugated inactive ABA sinks, thus restricting stomatal closure. ABCG17 and ABCG18 double knockdown revealed that the transporters encoded by these genes not only limit stomatal aperture size, conductance and transpiration while increasing water-use efficiency but also control ABA translocation from the shoot to the root to regulate lateral root emergence. Under abiotic stress conditions, ABCG17 and ABCG18 are transcriptionally repressed, promoting active ABA movement and response. The transport mechanism mediated by ABCG17 and ABCG18 allows plants to maintain ABA homeostasis under normal growth conditions.

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