Decreased Levels of Thioredoxin o1 Influences Stomatal Development and Aperture but Not Photosynthesis under Non-Stress and Saline Conditions

Salinity has a negative impact on plant growth, with photosynthesis being downregulated partially due to osmotic effect and enhanced cellular oxidation. Redox signaling contributes to the plant response playing thioredoxins (TRXs) a central role. In this work we explore the potential contribution of Arabidopsis TRXo1 to the photosynthetic response under salinity analyzing Arabidopsis wild-type (WT) and two Attrxo1 mutant lines in their growth under short photoperiod and higher light intensity than previous reported works. Stomatal development and apertures and the antioxidant, hormonal and metabolic acclimation are also analyzed. In control conditions mutant plants displayed less and larger developed stomata and higher pore size which could underlie their higher stomatal conductance, without being affected in other photosynthetic parameters. Under salinity, all genotypes displayed a general decrease in photosynthesis and the oxidative status in the Attrxo1 mutant lines was altered, with higher levels of H2O2 and NO but also higher ascorbate/glutathione (ASC/GSH) redox states than WT plants. Finally, sugar changes and increases in abscisic acid (ABA) and NO may be involved in the observed higher stomatal response of the TRXo1-altered plants. Therefore, the lack of AtTRXo1 affected stomata development and opening and the mutants modulate their antioxidant, metabolic and hormonal responses to optimize their adaptation to salinity.

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Ectopic Overexpression of Histone H3K4 Methyltransferase CsSDG36 from Tea Plant Decreases Hyperosmotic Stress Tolerance in Arabidopsis thaliana

International Journal of Molecular Sciences ◽

10.3390/ijms22105064 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5064

Author(s):

Qinghua Chen ◽

Linghui Guo ◽

Yanwen Yuan ◽

Shuangling Hu ◽

Fei Guo ◽

...

Keyword(s):

Drought Stress ◽

Transmembrane Domain ◽

Tea Plant ◽

Microtubule Assembly ◽

Pcr Analysis ◽

Drought Response ◽

Stomatal Development ◽

Wild Type ◽

Over Expression ◽

Histone H3k4

Histone methylation plays an important regulatory role in the drought response of many plants, but its regulatory mechanism in the drought response of the tea plant remains poorly understood. Here, drought stress was shown to induce lower relative water content and significantly downregulate the methylations of histone H3K4 in the tea plant. Based on our previous analysis of the SET Domain Group (SDG) gene family, the full-length coding sequence (CDS) of CsSDG36 was cloned from the tea cultivar ‘Fuding Dabaicha’. Bioinformatics analysis showed that the open reading frame (ORF) of the CsSDG36 gene was 3138 bp, encoding 1045 amino acids and containing the conserved structural domains of PWWP, PHD, SET and PostSET. The CsSDG36 protein showed a close relationship to AtATX4 of the TRX subfamily, with a molecular weight of 118,249.89 Da, and a theoretical isoelectric point of 8.87, belonging to a hydrophilic protein without a transmembrane domain, probably located on the nucleus. The expression of CsSDG36 was not detected in the wild type, while it was clearly detected in the over-expression lines of Arabidopsis. Compared with the wild type, the over-expression lines exhibited lower hyperosmotic resistance by accelerating plant water loss, increasing reactive oxygen species (ROS) pressure, and increasing leaf stomatal density. RNA-seq analysis suggested that the CsSDG36 overexpression caused the differential expression of genes related to chromatin assembly, microtubule assembly, and leaf stomatal development pathways. qRT-PCR analysis revealed the significant down-regulation of stomatal development-related genes (BASL, SBT1.2(SDD1), EPF2, TCX3, CHAL, TMM, SPCH, ERL1, and EPFL9) in the overexpression lines. This study provides a novel sight on the function of histone methyltransferase CsSDG36 under drought stress.

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Ectopic overexpression of a type-II DGAT (CeDGAT2-2) derived from oil-rich tuber of Cyperus esculentus enhances accumulation of oil and oleic acid in tobacco leaves

Biotechnology for Biofuels ◽

10.1186/s13068-021-01928-8 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Yu Gao ◽

Yan Sun ◽

Huiling Gao ◽

Ying Chen ◽

Xiaoqing Wang ◽

...

Keyword(s):

Fatty Acids ◽

Oleic Acid ◽

Negative Impact ◽

Value Added ◽

Cyperus Esculentus ◽

Wild Type ◽

Tobacco Leaves ◽

Vegetative Tissues ◽

Oil Storage ◽

Tag Biosynthesis

Abstract Background Engineering triacylglycerol (TAG) accumulation in vegetative tissues of non-food crops has become a promising way to meet our increasing demand for plant oils, especially the renewable production of biofuels. The most important target modified in this regard is diacylglycerol acyltransferase (DGAT) enzyme responsible for the final rate-limiting step in TAG biosynthesis. Cyperus esculentus is a unique plant largely accumulating oleic acid-enriched oil in its underground tubers. We speculated that DGAT derived from such oil-rich tubers could function more efficiently than that from oleaginous seeds in enhancing oil storage in vegetative tissues of tobacco, a high-yielding biomass crops. Results Three CeDGAT genes namely CeDGAT1, CeDGAT2-1 and CeDGAT2-2 were identified in C. esculentus by mining transcriptome of developing tubers. These CeDGATs were expressed in tissues tested, with CeDGAT1 highly in roots, CeDGAT2-1 abundantly in leaves, and CeDGAT2-2 predominantly in tubers. Notably, CeDGAT2-2 expression pattern was in accordance with oil dynamic accumulation during tuber development. Overexpression of CeDGAT2-2 functionally restored TAG biosynthesis in TAG-deficient yeast mutant H1246. Oleic acid level was significantly increased in CeDGAT2-2 transgenic yeast compared to the wild-type yeast and ScDGA1-expressed control under culture with and without feeding of exogenous fatty acids. Overexpressing CeDGAT2-2 in tobacco led to dramatic enhancements of leafy oil by 7.15- and 1.7-fold more compared to the wild-type control and plants expressing Arabidopsis seed-derived AtDGAT1. A substantial change in fatty acid composition was detected in leaves, with increase of oleic acid from 5.1% in the wild type to 31.33% in CeDGAT2-2-expressed tobacco and accompanied reduction of saturated fatty acids. Moreover, the elevated accumulation of oleic acid-enriched TAG in transgenic tobacco exhibited no significantly negative impact on other agronomic traits such as photosynthesis, growth rates and seed germination except for small decline of starch content. Conclusions The present data indicate that CeDGAT2-2 has a high enzyme activity to catalyze formation of TAG and a strong specificity for oleic acid-containing substrates, providing new insights into understanding oil biosynthesis mechanism in plant vegetative tissues. Overexpression of CeDGAT2-2 alone can significantly increase oleic acid-enriched oil accumulation in tobacco leaves without negative impact on other agronomy traits, showing CeDGAT2-2 as the desirable target gene in metabolic engineering to enrich oil and value-added lipids in high-biomass plants for commercial production of biofuel oils.

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Negative impact of tissue inhibitor of metalloproteinase-3 null mutation on lung structure and function in response to sepsis

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00141.2003 ◽

2003 ◽

Vol 285 (6) ◽

pp. L1222-L1232 ◽

Cited By ~ 37

Author(s):

Erica L. Martin ◽

Brent Z. Moyer ◽

M. Cynthia Pape ◽

Barry Starcher ◽

Kevin J. Leco ◽

...

Keyword(s):

Negative Impact ◽

Cecal Ligation ◽

Lung Compliance ◽

Tissue Inhibitor Of Metalloproteinase ◽

Tissue Inhibitors Of Metalloproteinases ◽

Wild Type ◽

Gelatinase Activity ◽

Lung Structure ◽

And Function ◽

Knockout Animals

Matrix metalloproteinases (MMPs) are degradative enzymes, which act to remodel tissue. Their activity is regulated by the tissue inhibitors of metalloproteinases (TIMPs). An imbalance in the degradation/inhibition activities has been associated with many diseases, including sepsis. We have previously shown that TIMP-3 knockout animals develop spontaneous, progressive air space enlargement. The objectives of this study were to determine the effects of a septic lung stress induced by cecal ligation and perforation (CLP) on lung function, structure, pulmonary surfactant, and inflammation in TIMP-3 null mice. Knockout and wild-type animals were randomized to either sham or CLP surgery, allowed to recover for 6 h, and then euthanized. TIMP-3 null animals exposed to sham surgery had a significant increase in lung compliance when compared with sham wild-type mice. Additionally, the TIMP-3 knockout mice showed a significant increase in compliance following CLP. Rapid compliance changes were accompanied by significantly decreased collagen and fibronectin levels and increased gelatinase (MMP-2 and -9) abundance and activation. Additionally, in situ zymography showed increased airway-associated gelatinase activity in the knockout animals enhanced following CLP. In conclusion, exposing TIMP-3 null animals to sepsis rapidly enhances the phenotypic abnormalities of these mice, due to increased MMP activity induced by CLP.

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Alpha Carbonic Anhydrase 5 Mediates Stimulation of ATP Synthesis by Bicarbonate in Isolated Arabidopsis Thylakoids

Frontiers in Plant Science ◽

10.3389/fpls.2021.662082 ◽

2021 ◽

Vol 12 ◽

Author(s):

Tatiana P. Fedorchuk ◽

Inga A. Kireeva ◽

Vera K. Opanasenko ◽

Vasily V. Terentyev ◽

Natalia N. Rudenko ◽

...

Keyword(s):

Mass Spectrometry ◽

Arabidopsis Thaliana ◽

Carbonic Anhydrase ◽

Atp Synthesis ◽

Thylakoid Membranes ◽

Wild Type ◽

Gene Encoding ◽

Mutant Lines ◽

Stimulation Of ◽

Soluble Carbonic Anhydrase

We studied bicarbonate-induced stimulation of photophosphorylation in thylakoids isolated from leaves of Arabidopsis thaliana plants. This stimulation was not observed in thylakoids of wild-type in the presence of mafenide, a soluble carbonic anhydrase inhibitor, and was absent in thylakoids of two mutant lines lacking the gene encoding alpha carbonic anhydrase 5 (αCA5). Using mass spectrometry, we revealed the presence of αCA5 in stromal thylakoid membranes of wild-type plants. A possible mechanism of the photophosphorylation stimulation by bicarbonate that involves αCA5 is proposed.

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Genetic analysis of the Arabidopsis TIR1/AFB auxin receptors reveals both overlapping and specialized functions

eLife ◽

10.7554/elife.54740 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 14

Author(s):

Michael J Prigge ◽

Matthieu Platre ◽

Nikita Kadakia ◽

Yi Zhang ◽

Kathleen Greenham ◽

...

Keyword(s):

Genetic Analysis ◽

Early Embryo ◽

Wild Type ◽

The Family ◽

Dependent Inhibition ◽

Root Gravitropism ◽

Specialized Function ◽

Mutant Lines

The TIR1/AFB auxin co-receptors mediate diverse responses to the plant hormone auxin. The Arabidopsis genome encodes six TIR1/AFB proteins representing three of the four clades that were established prior to angiosperm radiation. To determine the role of these proteins in plant development we performed an extensive genetic analysis involving the generation and characterization of all possible multiply-mutant lines. We find that loss of all six TIR1/AFB proteins results in early embryo defects and eventually seed abortion, and yet a single wild-type allele of TIR1 or AFB2 is sufficient to support growth throughout development. Our analysis reveals extensive functional overlap between even the most distantly related TIR1/AFB genes except for AFB1. Surprisingly, AFB1 has a specialized function in rapid auxin-dependent inhibition of root growth and early phase of root gravitropism. This activity may be related to a difference in subcellular localization compared to the other members of the family.

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Mutagenesis development of actinoplanes sp. KCTC 9161 by N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and screening for acarbose production

Vietnam Journal of Biotechnology ◽

10.15625/1811-4989/14/4/12310 ◽

2018 ◽

Vol 14 (4) ◽

pp. 753-760

Author(s):

Do Thi Tuyen ◽

Nguyen The Duong ◽

Le Thanh Hoang

Keyword(s):

Type Ii Diabetes ◽

Wild Type Strain ◽

Fermentation Medium ◽

Original Strain ◽

Wild Type ◽

Chromatography Method ◽

Mutant Strains ◽

Insulin Dependent ◽

Mutant Lines ◽

Layer Chromatography

Acarbose has been widely used in the therapy of type II diabetes (non-insulin dependent) because it controls blood sugar contents of patients after meals. Acarbose, a pseudo-oligosaccharide, acts as a competitive -glucosidase inhibitor. Acarbose is produced by the strains of Bacillus, Streptomyces and Actinoplanes sp. The aim of this study was to develop mutagenesis for an Actinoplanes sp. strain and screening for acarbose production. The spores of Actinoplanes sp. KCTC 9161 strain were subjected to be mutated by N-methyl-N'-nitro-N-nitrosoguanidine (NTG) for screening and finding mutant strains that were capable of production of higher acarbose (an inhibitor of α-glucosidase) higher than wild type strain. Firstly, the original NTG solution was prepared in phosphate buffer 0.05 M, pH 6.9 and the safety concentration of NTG was determined at 5 mg/ml. Then, the spores were incubated with different NTG amounts and duration. The living colonies were transferred to fermentation medium. The results obtained showed that 15 mutant strains were produced higher acarbose than wild type when used thin layer chromatography method for analysis and comparing with standard acarbose (Sigma). Three cell lines among total tested 15 mutant lines of Actinoplanes sp. KCTC 9161 produced acarbose at a higher level or indicated a higher inhibitory activity toward α-glucosidase than the original strain. Enzymatic inhibitory ativity of α-glucosidase of three mutant strains (Actinoplanes sp. KCTC- L4, L11, L14) was increased 1.3 fold higher than wild type and Actinoplanes sp. KCTC spores were very sensitive to NTG toxic, 98% spores could not survive at the treatment condition of 50 µg NTG for 30 minutes. In addition, an applicable protocol for mutating Actinoplanes sp. using NTG was suggested for further research.

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Multiple effects of the starch synthase II mutation in developing wheat endosperm

Functional Plant Biology ◽

10.1071/fp06288 ◽

2007 ◽

Vol 34 (5) ◽

pp. 431 ◽

Cited By ~ 23

Author(s):

Behjat Kosar-Hashemi ◽

Zhongyi Li ◽

Oscar Larroque ◽

Ahmed Regina ◽

Makoto Yamamori ◽

...

Keyword(s):

Triticum Aestivum L ◽

Endosperm Development ◽

Starch Synthase ◽

Starch Granules ◽

Branching Enzyme ◽

Wild Type ◽

Drastic Reduction ◽

Branching Patterns ◽

Soluble Phase ◽

Mutant Lines

A line of wheat (Triticum aestivum L.), sgp-1, that does not express starch synthase II (SSII, also known as SGP-1) has previously been reported. In this study, F1 derived doubled haploid lines with homozygous wild type or mutant alleles for SGP-1 genes were identified from a cross between the original mutant and a wild type Australian cultivar. Analysis of the starch granules showed that in the mutant lines they are markedly distorted from 15 days postanthesis during grain development. Starch branching patterns showed an increase in the proportion of short chains (DP 6–10) at an earlier stage, but this increase became much more pronounced at 15 days postanthesis and persisted until maturity. There was also a consistent and drastic reduction throughout seed development in the relative amounts of starch branching enzyme II (SBEII, comprising SBEIIa and SBEIIb) and starch synthase I (SSI) bound to the starch granules. In the soluble phase, however, there was relatively little change in the amount of SBEIIb, SBEIIa or SSI protein. Therefore loss of SSII specifically leads to the loss of SBEIIb, SBEIIa and SSI protein in the granule-bound phase and the effect of this mutation is clearly manifest from the mid-stage of endosperm development in wheat.

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Epoxide hydrolase 3 (Ephx3) gene disruption reduces ceramide linoleate epoxide hydrolysis and impairs skin barrier function

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.016570 ◽

2020 ◽

pp. jbc.RA120.016570

Author(s):

Matthew L. Edin ◽

Haruto Yamanashi ◽

William E. Boeglin ◽

Joan P. Graves ◽

Laura M. DeGraff ◽

...

Keyword(s):

Epoxide Hydrolase ◽

Skin Barrier ◽

Skin Barrier Function ◽

Potential Contribution ◽

Wild Type ◽

Lipoxygenase Pathway ◽

Physiological Relevance ◽

Hydrolysis Of

The mammalian epoxide hydrolase EPHX3 is known from in vitro experiments to efficiently hydrolyze the linoleate epoxides 9,10-epoxyoctadecamonoenoic acid (EpOME) and epoxyalcohol 9R,10R-trans-epoxy-11E-13R-hydroxy-octadecenoate to corresponding diols and triols, respectively. Herein we examined the physiological relevance of EPHX3 to hydrolysis of both substrates in vivo. Ephx3-/- mice show no deficiency in EpOME-derived plasma diols, discounting a role for EPHX3 in their formation, whereas epoxyalcohol-derived triols esterified in acylceramides of the epidermal 12R-lipoxygenase pathway are reduced. Although the Ephx3-/- pups appear normal, measurements of trans-epidermal water loss detected a modest and statistically significant increase compared to the wild-type or heterozygote mice, reflecting a skin barrier impairment that was not evident in the knockouts of mouse microsomal epoxide hydrolase (EPHX1/mEH) or soluble epoxide hydrolase (EPHX2/sEH). This barrier phenotype in the Ephx3-/- pups was associated with a significant decrease in the covalently bound ceramides in the epidermis (40% reduction, p<0.05), indicating a corresponding structural impairment in the integrity of the water barrier. Quantitative LC-MS analysis of the esterified linoleate-derived triols in the murine epidermis revealed a marked and isomer-specific reduction (~85%) in the Ephx3-/- epidermis of the major trihydroxy isomer 9R,10S,13R-trihydroxy-11E-octadecenoate. We conclude EPHX3 (and not EPHX1 or EPHX2) catalyzes hydrolysis of the 12R-LOX/eLOX3-derived epoxyalcohol esterified in acylceramide, and may function to control flux through the alternative and crucial route of metabolism via the dehydrogenation pathway of SDR9C7. Importantly, our findings also identify a functional role for EPHX3 in transformation of a naturally esterified epoxide substrate, pointing to its potential contribution in other tissues.

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The Arabidopsis ALDP protein homologue COMATOSE is instrumental in peroxisomal acetate metabolism

Biochemical Journal ◽

10.1042/bj20070258 ◽

2007 ◽

Vol 406 (3) ◽

pp. 399-406 ◽

Cited By ~ 37

Author(s):

Mark A. Hooks ◽

James E. Turner ◽

Elaine C. Murphy ◽

Katherine A. Johnston ◽

Sally Burr ◽

...

Keyword(s):

Glyoxylate Cycle ◽

Sequence Length ◽

Acetate Metabolism ◽

Soluble Carbohydrate ◽

Wild Type ◽

Abc Protein ◽

Atp Binding Cassette Transporter ◽

Mutant Lines ◽

Simple Sequence

The Arabidopsis acn (acetate non-utilizing) mutants were isolated by fluoroacetate-resistant germination and seedling establishment. We report the characterization of the acn2 mutant. Physiological analyses of acn2 showed that it possessed characteristics similar to those of the mutants cts (COMATOSE)-1 and pxa [peroxisomal ABC (ATP-binding-cassette) transporter]1. The acn2 locus was mapped to within 3 cM of the CTS gene on the bottom arm of chromosome IV using CAPS (cleavage amplification polymorphism) and SSLP (simple sequence-length polymorphism) markers. Crossing acn2 and cts-1 failed to restore the fluoroacetate-sensitive phenotype, suggesting that these mutations were allelic. Sequencing of the ACN2 locus revealed a C→T nonsense mutation in exon 13, which would have resulted in the elimination of the C-terminal hemitransporter domain of the encoded protein. Neither the full-length CTS protein nor the truncated protein was detected on immunoblots using either C-terminal- or N-terminal-specific anti-CTS antibodies respectively, demonstrating the absence of the entire CTS protein in acn2 mutants. Emerged seedlings of both cts-1 and pxa1 alleles displayed increased resistance to FAc (monofluoroacetic acid) compared with the corresponding wild-type seedlings. Complementation studies showed that mutation of the CTS gene was responsible for the FAc-resistant phenotype, as when the wild-type protein was expressed in both the cts-1 and pxa1 mutant lines, the strains became FAc-sensitive. Feeding studies confirmed that both acn2 and cts-1 mutants were compromised in their ability to convert radiolabelled acetate into soluble carbohydrate. These results demonstrate a role for the ABC protein CTS in providing acetate to the glyoxylate cycle in developing seedlings.

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