scholarly journals Lack of Correlation between Ammonium Accumulation and Survival of Transgenic Birch Plants with Pine Cytosolic Glutamine Synthetase Gene after “Basta” Herbicide Treatment

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Vadim Lebedev ◽  
Vyacheslav Faskhiev ◽  
Konstantin Shestibratov
Keyword(s):  
Transgenic Plants ◽  
Glutamine Synthetase ◽  
Leaf Tissue ◽  
Ammonium Toxicity ◽  
Ammonium Accumulation ◽  
Herbicide Treatment ◽  
Genes Encoding ◽  
Transgenic Lines ◽  
On Line ◽  
Increase Productivity

Transformation of plants with genes encoding a glutamine synthetase (GS), a key nitrogen metabolism enzyme, is usually used to increase productivity. However, overexpression of these genes may increase resistance to phosphinothricin (PPT) that irreversibly inhibits GS causing ammonium accumulation in plant tissues. Transgenic plants of two birch (Betula pubescens) genotypes expressing a pine cytosolic GS gene were used for studying the PPT effect on trees. Two control and 8 transgenic lines were treated with herbicide “Basta” at dose equivalent to 2.5 and 5 Lha−1. Necrosis and abscission of leaves occurred irrespective of a transgenic status or the treatment dose. Ammonium content in leaf tissue in 3 days after the 5 Lha−1 treatment was substantially increased in all plants, 3.2–16.0 times depending on line. After the 2.5 Lha−1 treatment, ammonium content in three transgenic lines was not different from that in control variant sprayed with water. The herbicide treatment caused more prominent desiccation in the bp3f1 genotype nontransgenic plants as compared to transgenic plants, but not in the bp4a genotype. Lack of correlation between ammonium levels and survival of transgenic plants suggests that ammonium toxicity is not a main reason for the birch plant death after the PPT treatment.

scholarly journals Excessive assimilation of ammonium by plastidic glutamine synthetase is a major cause of ammonium toxicity in Arabidopsis thaliana

2019 ◽  
Author(s):  
Takushi Hachiya ◽  
Jun Inaba ◽  
Mayumi Wakazaki ◽  
Mayuko Sato ◽  
Kiminori Toyooka ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Nitrate Assimilation ◽  
Nitrogen Sources ◽  
Ammonium Assimilation ◽  
Ammonia Solution ◽  
Acidic Stress ◽  
Ammonium Toxicity ◽  
Ammonium Accumulation ◽  
Concomitant Reduction ◽  
High Concentrations

AbstractPlants use nitrate and ammonium in the soil as their main nitrogen sources. Recently, ammonium has attracted attention due to evidence suggesting that, in C3 species, an elevated CO2 environment inhibits nitrate assimilation. However, high concentrations of ammonium as the sole nitrogen source for plants causes impaired growth, i.e. ammonium toxicity. Although ammonium toxicity has been studied for a long time, the primary cause remains to be elucidated. Here, we show that ammonium assimilation in plastids rather than ammonium accumulation is a primary cause for toxicity. Our genetic screen of ammonium-tolerant Arabidopsis lines with enhanced shoot growth identified plastidic GLUTAMINE SYNTHETASE 2 (GLN2) as the causal gene. Our reciprocal grafting of wild-type and GLN2 or GLN1;2-deficient lines suggested that shoot GLN2 activity results in ammonium toxicity, whilst root GLN1;2 activity prevents it. With exposure to toxic levels of ammonium, the shoot GLN2 reaction produced an abundance of protons within cells, thereby elevating shoot acidity and stimulating expression of acidic stress-responsive genes. Application of an alkaline ammonia solution to the toxic ammonium medium efficiently alleviated the ammonium toxicity with a concomitant reduction in shoot acidity. Consequently, we conclude that a primary cause of ammonium toxicity is acidic stress in the shoot. This fundamental insight provides a framework for enhanced understanding of ammonium toxicity in plants.

scholarly journals Excessive ammonium assimilation by plastidic glutamine synthetase causes ammonium toxicity in Arabidopsis thaliana

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Takushi Hachiya ◽  
Jun Inaba ◽  
Mayumi Wakazaki ◽  
Mayuko Sato ◽  
Kiminori Toyooka ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Sources ◽  
Ammonium Assimilation ◽  
Ammonia Solution ◽  
Acidic Stress ◽  
Ammonium Toxicity ◽  
Ammonium Accumulation ◽  
Concomitant Reduction ◽  
Ammonium Nutrition ◽  
Near Future

AbstractPlants use nitrate, ammonium, and organic nitrogen in the soil as nitrogen sources. Since the elevated CO2 environment predicted for the near future will reduce nitrate utilization by C3 species, ammonium is attracting great interest. However, abundant ammonium nutrition impairs growth, i.e., ammonium toxicity, the primary cause of which remains to be determined. Here, we show that ammonium assimilation by GLUTAMINE SYNTHETASE 2 (GLN2) localized in the plastid rather than ammonium accumulation is a primary cause for toxicity, which challenges the textbook knowledge. With exposure to toxic levels of ammonium, the shoot GLN2 reaction produced an abundance of protons within cells, thereby elevating shoot acidity and stimulating expression of acidic stress-responsive genes. Application of an alkaline ammonia solution to the ammonium medium efficiently alleviated the ammonium toxicity with a concomitant reduction in shoot acidity. Consequently, we conclude that a primary cause of ammonium toxicity is acidic stress.

scholarly journals Genome sequencing of four culinary herbs reveals terpenoid genes underlying chemodiversity in the Nepetoideae

DNA Research ◽  
2020 ◽  
Vol 27 (3) ◽  
Author(s):  
Nolan Bornowski ◽  
John P Hamilton ◽  
Pan Liao ◽  
Joshua C Wood ◽  
Natalia Dudareva ◽  
...  
Keyword(s):  
Leaf Tissue ◽  
Terpene Synthases ◽  
Genomic Analyses ◽  
Genes Encoding ◽  
Medicinal Properties ◽  
Culinary Herbs ◽  
Rosmarinus Officinalis L ◽  
Origanum Majorana ◽  
Genome Assemblies ◽  
High Quality Genome

Abstract Species within the mint family, Lamiaceae, are widely used for their culinary, cultural, and medicinal properties due to production of a wide variety of specialized metabolites, especially terpenoids. To further our understanding of genome diversity in the Lamiaceae and to provide a resource for mining biochemical pathways, we generated high-quality genome assemblies of four economically important culinary herbs, namely, sweet basil (Ocimum basilicum L.), sweet marjoram (Origanum majorana L.), oregano (Origanum vulgare L.), and rosemary (Rosmarinus officinalis L.), and characterized their terpenoid diversity through metabolite profiling and genomic analyses. A total 25 monoterpenes and 11 sesquiterpenes were identified in leaf tissue from the 4 species. Genes encoding enzymes responsible for the biosynthesis of precursors for mono- and sesqui-terpene synthases were identified in all four species. Across all 4 species, a total of 235 terpene synthases were identified, ranging from 27 in O. majorana to 137 in the tetraploid O. basilicum. This study provides valuable resources for further investigation of the genetic basis of chemodiversity in these important culinary herbs.

Over-expression of the rice OsAMT1-1 gene increases ammonium uptake and content, but impairs growth and development of plants under high ammonium nutrition

2006 ◽  
Vol 33 (2) ◽  
pp. 153 ◽  
Author(s):  
Mohammad S. Hoque ◽  
Josette Masle ◽  
Michael K. Udvardi ◽  
Peter R. Ryan ◽  
Narayana M. Upadhyaya
Keyword(s):  
Transgenic Plants ◽  
Ammonium Assimilation ◽  
Ammonium Transporter ◽  
Ammonium Uptake ◽  
Vegetative Stage ◽  
Over Expression ◽  
Transgenic Lines ◽  
Ammonium Nutrition ◽  
Maize Ubiquitin Promoter

A transgenic approach was undertaken to investigate the role of a rice ammonium transporter (OsAMT1-1) in ammonium uptake and consequent ammonium assimilation under different nitrogen regimes. Transgenic lines overexpressing OsAMT1-1 were produced by Agrobacterium-mediated transformation of two rice cultivars, Taipei 309 and Jarrah, with an OsAMT1-1 cDNA gene construct driven by the maize ubiquitin promoter. Transcript levels of OsAMT1-1 in both Taipei 309 and Jarrah transgenic lines correlated positively with transgene copy number. Shoot and root biomass of some transgenic lines decreased during seedling and early vegetative stage compared to the wild type, especially when grown under high (2 mm) ammonium nutrition. Transgenic plants, particularly those of cv. Jarrah recovered in the mid-vegetative stage under high ammonium nutrition. Roots of the transgenic plants showed increased ammonium uptake and ammonium content. We conclude that the decreased biomass of the transgenic lines at early stages of growth might be caused by the accumulation of ammonium in the roots owing to the inability of ammonium assimilation to match the greater ammonium uptake.

scholarly journals Exogenous Promoter Triggers APETALA3 Silencing through RNA-Directed DNA Methylation Pathway in Arabidopsis

2019 ◽  
Vol 20 (18) ◽  
pp. 4478 ◽  
Author(s):  
Benqi Wang ◽  
Jie Liu ◽  
Lei Chu ◽  
Xue Jing ◽  
Huadong Wang ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Molecular Mechanisms ◽  
Plant Reproduction ◽  
Vital Role ◽  
Abnormal Development ◽  
Class A ◽  
Methylation Pathway ◽  
Class B ◽  
Transgenic Lines ◽  
Morphological Defects

The development of floral organs plays a vital role in plant reproduction. In our research, the APETALA3 (AP3) promoter-transgenic lines showed abnormal developmental phenotypes in stamens and petals. The aim of this study is to understand the molecular mechanisms of the morphological defects in transgenic plants. By performing transgenic analysis, it was found that the AP3-promoted genes and the vector had no relation to the morphological defects. Then, we performed the expression analysis of the class A, B, and C genes. A dramatic reduction of transcript levels of class B genes (AP3 and PISTILLATA) was observed. Additionally, we also analyzed the methylation of the promoters of class B genes and found that the promoter of AP3 was hypermethylated. Furthermore, combining mutations in rdr2-2, drm1/2, and nrpd1b-11 with the AP3-silencing lines rescued the abnormal development of stamens and petals. The expression of AP3 was reactivated and the methylation level of AP3 promoter was also reduced in RdDM-defective AP3-silencing lines. Our results showed that the RdDM pathway contributed to the transcriptional silencing in the transgenic AP3-silencing lines. Moreover, the results revealed that fact that the exogenous fragment of a promoter could trigger the methylation of homologous endogenous sequences, which may be ubiquitous in transgenic plants.

scholarly journals A Novel WRKY Transcription Factor from Ipomoea trifida, ItfWRKY70, Confers Drought Tolerance in Sweet Potato

2022 ◽  
Vol 23 (2) ◽  
pp. 686
Author(s):  
Sifan Sun ◽  
Xu Li ◽  
Shaopei Gao ◽  
Nan Nie ◽  
Huan Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Transgenic Plants ◽  
Drought Tolerance ◽  
Sweet Potato ◽  
Stress Responses ◽  
Leaf Tissue ◽  
Stomatal Aperture ◽  
Ros Scavenging ◽  
Ipomoea Trifida ◽  
Positive Role

WRKY transcription factors are one of the important families in plants, and have important roles in plant growth, abiotic stress responses, and defense regulation. In this study, we isolated a WRKY gene, ItfWRKY70, from the wild relative of sweet potato Ipomoea trifida (H.B.K.) G. Don. This gene was highly expressed in leaf tissue and strongly induced by 20% PEG6000 and 100 μM abscisic acid (ABA). Subcellar localization analyses indicated that ItfWRKY70 was localized in the nucleus. Overexpression of ItfWRKY70 significantly increased drought tolerance in transgenic sweet potato plants. The content of ABA and proline, and the activity of SOD and POD were significantly increased, whereas the content of malondialdehyde (MDA) and H2O2 were decreased in transgenic plants under drought stress. Overexpression of ItfWRKY70 up-regulated the genes involved in ABA biosynthesis, stress-response, ROS-scavenging system, and stomatal aperture in transgenic plants under drought stress. Taken together, these results demonstrated that ItfWRKY70 plays a positive role in drought tolerance by accumulating the content of ABA, regulating stomatal aperture and activating the ROS scavenging system in sweet potato.

scholarly journals RabA2b Overexpression Alters the Plasma-Membrane Proteome and Improves Drought Tolerance in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Vivek Ambastha ◽  
Ifat Matityahu ◽  
Dafna Tidhar ◽  
Yehoram Leshem
Keyword(s):  
Plasma Membrane ◽  
Transgenic Plants ◽  
Drought Tolerance ◽  
Small Gtpases ◽  
Plant Responses ◽  
Rab Proteins ◽  
Strong Activity ◽  
Native Promoter ◽  
Transgenic Lines ◽  
Drought Resistant

Rab proteins are small GTPases that are important in the regulation of vesicle trafficking. Through data mining, we identified RabA2b to be stress responsive, though little is known about the involvement of RabA in plant responses to abiotic stresses. Analysis of the RabA2b native promoter showed strong activity during osmotic stress, which required the stress hormone Abscisic acid (ABA) and was restricted to the vasculature. Sequence analysis of the promoter region identified predicted binding motifs for several ABA-responsive transcription factors. We cloned RabA2b and overexpressed it in Arabidopsis. The resulting transgenic plants were strikingly drought resistant. The reduced water loss observed in detached leaves of the transgenic plants could not be explained by stomatal aperture or density, which was similar in all the genotypes. Subcellular localization studies detected strong colocalization between RabA2b and the plasma membrane (PM) marker PIP2. Further studies of the PM showed, for the first time, a distinguished alteration in the PM proteome as a result of RabA2b overexpression. Proteomic analysis of isolated PM fractions showed enrichment of stress-coping proteins as well as cell wall/cuticle modifiers in the transgenic lines. Finally, the cuticle permeability of transgenic leaves was significantly reduced compared to the wild type, suggesting that it plays a role in its drought resistant properties. Overall, these data provide new insights into the roles and modes of action of RabA2b during water stresses, and indicate that increased RabA2b mediated PM trafficking can affect the PM proteome and increase drought tolerance.

Pseudopestalotiopsis gilvanii sp. nov. and Neopestalotiopsis formicarum leaves spot pathogens from guarana plant: a new threat to global tropical hosts

Phytotaxa ◽  
2021 ◽  
Vol 489 (2) ◽  
pp. 121-139
Author(s):  
GILVANA F. GUALBERTO ◽  
ARICLÉIA DE M. CATARINO ◽  
THIAGO F. SOUSA ◽  
JEFERSON C. CRUZ ◽  
ROGÉRIO E. HANADA ◽  
...  
Keyword(s):  
Plant Pathogen ◽  
Elaeis Guineensis ◽  
Elongation Factor ◽  
Leaf Tissue ◽  
Euterpe Oleracea ◽  
Internal Transcribed Spacer Region ◽  
Tropical Regions ◽  
Tropical Plants ◽  
Wide Range ◽  
Genes Encoding

Pestalotioid species (Pestalotiopsis, Pseudopestalotiopsis and Neopestalotiopsis) cause extremely damaging diseases in a wide range of hosts across the word. Recently, pestalotioid strains isolated from damaged guarana leaf tissue were subject to morphological and molecular characterization. Six monosporic isolates were obtained and analysed based on the following conidial characters: length, width, septation, absence or presence of basal appendage, number and length of apical appendages. For phylogenetic inference, sequences of the Internal Transcribed Spacer region (ITS), partial sequences of the genes encoding the translation elongation factor 1-α (tef1-α) and β-tubulin (tub2) were used. Three out of six strains analysed were identified as Neopestalotiopsis formicarum, while the three other isolates are described here as a new species of Pseudopestalotiopsis, named Ps. gilvanii sp. nov.. The pathogenicity of N. formicarum and Ps. gilvanii were confirmed following Koch’s postulate. Besides guarana, the potential of N. formicaram and Ps. gilvanii to cause diseases in other economically important tropical plants were investigated. Ps. gilvanii was pathogenic to açaí palms (Euterpe oleracea, E. precatoria), and oil palm (Elaeis guineensis), but not to banana (Musa paradisiaca var. pacovan) and rubber trees (Hevea brasiliensis). N. formicarum was not pathogenic to rubber trees but was pathogenic to other species tested. To our knowledge this is the first report of N. formicarum as a plant pathogen in the guarana plant, and Ps. gilvanii as novel plant pathogen capable of causing disease in important plant crops from tropical regions.

Transcriptomic and metabolomic profiling reveals the effect of LED light quality on morphological traits, and phenylpropanoid-derived compounds accumulation in Sarcandra glabra seedlings

2020 ◽  
Author(s):  
Dejin Xie ◽  
Lingyan Chen ◽  
Chengcheng Zhou ◽  
Muhammad Waqqas Khan Tarin ◽  
Deming Yang ◽  
...  
Keyword(s):  
Leaf Area ◽  
Regulatory Mechanism ◽  
Substantial Reduction ◽  
Leaf Tissue ◽  
Influential Factor ◽  
Led Light ◽  
Metabolomic Profiling ◽  
Red Led ◽  
Genes Encoding ◽  
The Impact

Abstract Background: Sarcandra glabra is an evergreen and traditional Chinese herb with anti-oxidant, anti-bacterial, anti-inflammatory, and anti-tumor effects. Light is one of the most influential factor affecting the growth and quality of herbs. In recent times, the introduction of Light Emission Diode (LED) technology has been widely used for plants in greenhouse. However, the impact of such lights on plant growth and the regulatory mechanism of phenylpropanoid-derived compounds in S. glabra remain unclear. Results: The red LED light (RL) substantially increased the plant height and decreased the stem diameter and leaf area relative to the white LED light (WL), while the blue LED light (BL) significantly reduced the height and leaf area of S. glabra. According to transcriptomic profiling, 861, 378, 47, 10,033, 7917, and 6379 differentially expressed genes (DEGs) were identified among the groups of leaf tissue under BL (BY) vs. leaf tissue under RL (RY), BY vs. leaf tissue under WL (WY), RY vs. WY, root tissue under WL (WG) vs. WY, stem tissue under WL (WJ) vs. WG, and WJ vs. WY, respectively. We identified 46 genes encoding for almost all known enzymes involved in phenylpropanoid biosynthesis, e.g., phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), and flavonol synthase (FLS). We found 53 genes encoding R2R3-MYB proteins and bHLH proteins, respectively, where several were related to flavonoids biosynthesis. A total of 454 metabolites were identified based on metabolomic profiling, of which 44, 87, and 296 compounds were differentially produced in WY vs. RY, WY vs. BY, and WY vs. WG. In BY there was a substantial reduction in the production of esculetin, caffeic acid, isofraxidin, and fraxidin, while the yields of quercitrin and kaempferol were significantly up-regulated. In RY, the contents of cryptochlorogenic acid, cinnamic acid, and kaempferol decreased significantly. Besides, in WG, the production of metabolites (e.g. chlorogenic acid, cryptochlorogenic acid, and scopolin) declined, while their yields increased significantly (e.g. esculetin, fraxetin, isofraxidin, and fraxidin).Conclusion: These results provide further insight into the regulatory mechanism of accumulation patterns of phenylpropanoid-derived compounds in S. glabra under various light conditions, allowing optimum breeding conditions to be developed for this plant.

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