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.

TheAzospirillum brasilense rpoNgene is involved in nitrogen fixation, nitrate assimilation, ammonium uptake, and flagellar biosynthesis

1996 ◽  
Vol 42 (5) ◽  
pp. 467-478 ◽  
Author(s):  
Anne Milcamps ◽  
Anne Van Dommelen ◽  
John Stigter ◽  
Jos Vanderleyden ◽  
Frans J. de Bruijn
Keyword(s):  
Nitrogen Fixation ◽  
Azospirillum Brasilense ◽  
Nitrate Assimilation ◽  
Ammonium Assimilation ◽  
Gene Replacement ◽  
Ammonium Uptake ◽  
Significant Similarity ◽  
Sigma 54 ◽  
Azospirillum Brasilense Sp7

The rpoN (ntrA) gene (encoding sigma 54) of Azospirillum brasilense Sp7 was isolated by using conserved rpoN primers and the polymerase chain reaction, and its nucleotide sequence was determined. The deduced amino acid sequence of the RpoN protein was found to share a high degree of homology with other members of the sigma 54 family. Two additional open reading frames were found in the Azospirillum brasilense rpoN region, with significant similarity to equivalent regions surrounding the rpoN locus in other bacteria. An rpoN mutant of Azospirillum brasilense Sp7 was constructed by gene replacement and found to be defective in nitrogen fixation, nitrate assimilation, and ammonium uptake. Lack of ammonium uptake was also found in previously isolated Azospirillum brasilense ntrB and ntrC mutants, further supporting the role of the ntr system in this process. In addition, the rpoN mutant was found to be nonmotile, suggesting a role of RpoN in Azospirillum brasilense flagellar biosynthesis.Key words: Azospirillum brasilense, sigma factor, nitrogen fixation, ammonium assimilation, motility.

scholarly journals Ammonium and nitrate regulate NH4+ uptake activity of Arabidopsis ammonium transporter AtAMT1;3 via phosphorylation at multiple C-terminal sites

2019 ◽  
Vol 70 (18) ◽  
pp. 4919-4930 ◽  
Author(s):  
Xiangyu Wu ◽  
Ting Liu ◽  
Yongjian Zhang ◽  
Fengying Duan ◽  
Benjamin Neuhäuser ◽  
...  
Keyword(s):  
Fine Tuning ◽  
Ammonium Transporter ◽  
Ammonium Uptake ◽  
Nutrient Transporters ◽  
Complex Environments ◽  
Transport Activity ◽  
Arabidopsis Root ◽  
Ammonium Transporters ◽  
Uptake Activity

Abstract In plants, nutrient transporters require tight regulation to ensure optimal uptake in complex environments. The activities of many nutrient transporters are post-translationally regulated by reversible phosphorylation, allowing rapid adaptation to variable environmental conditions. Here, we show that the Arabidopsis root epidermis-expressed ammonium transporter AtAMT1;3 was dynamically (de-)phosphorylated at multiple sites in the cytosolic C-terminal region (CTR) responding to ammonium and nitrate signals. Under ammonium resupply rapid phosphorylation of a Thr residue (T464) in the conserved part of the CTR (CTRC) effectively inhibited AtAMT1;3-dependent NH4+ uptake. Moreover, phosphorylation of Thr (T494), one of three phosphorylation sites in the non-conserved part of the CTR (CRTNC), moderately decreased the NH4+ transport activity of AtAMT1;3, as deduced from functional analysis of phospho-mimic mutants in yeast, oocytes, and transgenic Arabidopsis. Double phospho-mutants indicated a role of T494 in fine-tuning the NH4+ transport activity when T464 was non-phosphorylated. Transient dephosphorylation of T494 with nitrate resupply closely paralleled a transient increase in ammonium uptake. These results suggest that T464 phosphorylation at the CTRC acts as a prime switch to prevent excess ammonium influx, while T494 phosphorylation at the CTRNC fine tunes ammonium uptake in response to nitrate. This provides a sophisticated regulatory mechanism for plant ammonium transporters to achieve optimal ammonium uptake in response to various nitrogen forms.

Over-Expression of a NAD-Malic Enzyme Gene from Rice in Arabidopsis thaliana Confers Tolerances to Several Abiotic Stresses

2011 ◽  
Vol 393-395 ◽  
pp. 863-866 ◽  
Author(s):  
Hao Zhou ◽  
Shen Kui Liu ◽  
Chuan Ping Yang
Keyword(s):  
Arabidopsis Thaliana ◽  
Abiotic Stresses ◽  
Malic Enzyme ◽  
Expression Vector ◽  
Enzyme Gene ◽  
Over Expression ◽  
Plant Expression Vector ◽  
Malic Enzyme Gene ◽  
Transgenic Lines

In order to investigate the role of a rice NAD-malic enzyme gene (OsNAD-ME1) under different abiotic stresses, OsNAD-ME1 was constructed into plant expression vector and transformed into Agrobacterium for infecting Arabidopsis thaliana. There were higher transcriptional levels of OsNAD-ME1 in homozygous transgenic lines compared with WT plants as well as higher NAD-ME activity. WT and transgenic Arabidopsis were treated with NaCl, NaHCO3, mannitol and H2O2. And then their root lengths, crown widths and fresh weights were measured and compared. The results showed that over-expression of OsNAD-ME1 in transgenic Arabidopsis increased the resistance to abiotic stresses, which indicated that OsNAD-ME1 was related to stress tolerance.

scholarly journals MaMAPK3-MaICE1-MaPOD P7 pathway, a positive regulator of cold tolerance in banana

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jie Gao ◽  
Tongxin Dou ◽  
Weidi He ◽  
Ou Sheng ◽  
Fangcheng Bi ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Cold Tolerance ◽  
Molecular Breeding ◽  
Cold Resistance ◽  
Oxidoreductase Activity ◽  
Tropical Fruit ◽  
Over Expression ◽  
Cavendish Banana ◽  
Cold Tolerant ◽  
Necrotic Symptoms

Abstract Background Banana is a tropical fruit with a high economic impact worldwide. Cold stress greatly affects the development and production of banana. Results In the present study, we investigated the functions of MaMAPK3 and MaICE1 involved in cold tolerance of banana. The effect of RNAi of MaMAPK3 on Dajiao (Musa spp. ‘Dajiao’; ABB Group) cold tolerance was evaluated. The leaves of the MaMAPK3 RNAi transgenic plants showed wilting and severe necrotic symptoms, while the wide-type (WT) plants remained normal after cold exposure. RNAi of MaMAPK3 significantly changed the expressions of the cold-responsive genes, and the oxidoreductase activity was significantly changed in WT plants, while no changes in transgenic plants were observed. MaICE1 interacted with MaMAPK3, and the expression level of MaICE1 was significantly decreased in MaMAPK3 RNAi transgenic plants. Over-expression of MaICE1 in Cavendish banana (Musa spp. AAA group) indicated that the cold resistance of transgenic plants was superior to that of the WT plants. The POD P7 gene was significantly up-regulated in MaICE1-overexpressing transgenic plants compared with WT plants, and the POD P7 was proved to interact with MaICE1. Conclusions Taken together, our work provided new and solid evidence that MaMAPK3-MaICE1-MaPOD P7 pathway positively improved the cold tolerance in monocotyledon banana, shedding light on molecular breeding for the cold-tolerant banana or other agricultural species.

scholarly journals Chandipura virus dysregulates the expression of hsa-miR-21-5p to activate NF-κB in human microglial cells

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Neha Pandey ◽  
Meghana Rastogi ◽  
Sunit K. Singh
Keyword(s):  
Expression Pattern ◽  
Case Fatality ◽  
Microglial Cells ◽  
Luciferase Assay ◽  
Western India ◽  
Cellular Mirnas ◽  
Over Expression ◽  
Chandipura Virus ◽  
Tnf Α

Abstract Background Chandipura virus (CHPV) is a negative single-stranded RNA virus of the Rhabdoviridae family. CHPV infection has been reported in Central and Western India. CHPV causes acute encephalitis with a case fatality rate of 70 % and mostly affects children below 15 years of age. CHPV infection in brain leads to neuronal apoptosis and activation of the microglial cells. The microRNAs (miRNAs) are small endogenous non-coding RNA that regulate the gene expression. Viral infections perturb the expression pattern of cellular miRNAs, which may in turn affect the expression pattern of downstream genes. This study aims to investigate hsa-miR-21-5p mediated regulation of PTEN, AKT, NF-ĸBp65, IL-6, TNF-α, and IL-1β, in human microglial cells during CHPV infection. Methods To understand the role of hsa-miR-21-5p in CHPV infection, the human microglial cells were infected with CHPV (MOI-0.1). Real-time PCR, western blotting, Luciferase assay, over-expression and knockdown techniques were used to understand the role of hsa-miR-21-5p in the regulation of PTEN, AKT and, NF-ĸBp65, IL-6, TNF-α, and IL-1β in this study. Results The hsa-miR-21-5p was found to be upregulated during CHPV infection in human microglial cells. This led to the downregulation of PTEN which promoted the phosphorylation of AKT and NF-ĸBp65. Over-expression of hsa-miR-21-5p led to the decreased expression of PTEN and promoted further phosphorylation of AKT and NF-ĸBp65 in human microglial cells. However, the inhibition of hsa-miR-21-5p using hsa-miR-21-5p inhibitor restored the expression. Conclusions This study supports the role of hsa-miR-21-5p in the regulation of pro-inflammatory genes in CHPV infected human microglial cells.

scholarly journals Transcriptomic and genetic approaches reveal an essential role of the NAC transcription factor SlNAP1 in the growth and defense response of tomato

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Jiao Wang ◽  
Chenfei Zheng ◽  
Xiangqi Shao ◽  
Zhangjian Hu ◽  
Jianxin Li ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Defense Response ◽  
Global Climate ◽  
Plant Responses ◽  
Multiple Stresses ◽  
Bacterial Diseases ◽  
Bacterial Wilt Disease ◽  
Transgenic Lines ◽  
Breeding Target

AbstractWith global climate change, plants are frequently being exposed to various stresses, such as pathogen attack, drought, and extreme temperatures. Transcription factors (TFs) play crucial roles in numerous plant biological processes; however, the functions of many tomato (Solanum lycopersicum L.) TFs that regulate plant responses to multiple stresses are largely unknown. Here, using an RNA-seq approach, we identified SlNAP1, a NAC TF-encoding gene, which was strongly induced by various stresses. By generating SlNAP1 transgenic lines and evaluating their responses to biotic and abiotic stresses in tomato, we found that SlNAP1-overexpressing plants showed significantly enhanced defense against two widespread bacterial diseases, leaf speck disease, caused by Pseudomonas syringae pv. tomato (Pst) DC3000, and root-borne bacterial wilt disease, caused by Ralstonia solanacearum. In addition, SlNAP1 overexpression dramatically improved drought tolerance in tomato. Although the SlNAP1-overexpressing plants were shorter than the wild-type plants during the early vegetative stage, eventually, their fruit yield increased by 10.7%. Analysis of different hormone contents revealed a reduced level of physiologically active gibberellins (GAs) and an increased level of salicylic acid (SA) and abscisic acid (ABA) in the SlNAP1-overexpressing plants. Moreover, EMSAs and ChIP-qPCR assays showed that SlNAP1 directly activated the transcription of multiple genes involved in GA deactivation and both SA and ABA biosynthesis. Our findings reveal that SlNAP1 is a positive regulator of the tomato defense response against multiple stresses and thus may be a potential breeding target for improving crop yield and stress resistance.

scholarly journals The activity status of cofilin is directly related to invasion, intravasation, and metastasis of mammary tumors

2006 ◽  
Vol 173 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Weigang Wang ◽  
Ghassan Mouneimne ◽  
Mazen Sidani ◽  
Jeffrey Wyckoff ◽  
Xiaoming Chen ◽  
...  
Keyword(s):  
Cell Motility ◽  
Cell Invasion ◽  
Actin Polymerization ◽  
Cancer Cell Invasion ◽  
Invasion And Metastasis ◽  
Over Expression ◽  
Cell Biol ◽  
Tumor Cell Motility ◽  
New Strategies

Understanding the mechanisms controlling cancer cell invasion and metastasis constitutes a fundamental step in setting new strategies for diagnosis, prognosis, and therapy of metastatic cancers. LIM kinase1 (LIMK1) is a member of a novel class of serine–threonine protein kinases. Cofilin, a LIMK1 substrate, is essential for the regulation of actin polymerization and depolymerization during cell migration. Previous studies have made opposite conclusions as to the role of LIMK1 in tumor cell motility and metastasis, claiming either an increase or decrease in cell motility and metastasis as a result of LIMK1 over expression (Zebda, N., O. Bernard, M. Bailly, S. Welti, D.S. Lawrence, and J.S. Condeelis. 2000. J. Cell Biol. 151:1119–1128; Davila, M., A.R. Frost, W.E. Grizzle, and R. Chakrabarti. 2003. J. Biol. Chem. 278:36868–36875; Yoshioka, K., V. Foletta, O. Bernard, and K. Itoh. 2003. Proc. Natl. Acad. Sci. USA. 100:7247–7252; Nishita, M., C. Tomizawa, M. Yamamoto, Y. Horita, K. Ohashi, and K. Mizuno. 2005. J. Cell Biol. 171:349–359). We resolve this paradox by showing that the effects of LIMK1 expression on migration, intravasation, and metastasis of cancer cells can be most simply explained by its regulation of the output of the cofilin pathway. LIMK1-mediated decreases or increases in the activity of the cofilin pathway are shown to cause proportional decreases or increases in motility, intravasation, and metastasis of tumor cells.

Elucidation of the role of glutathione reductase using transgenic plants

1994 ◽  
Vol 22 (4) ◽  
pp. 931-936 ◽  
Author(s):  
Philip Mullineaux ◽  
Gary Creissen ◽  
Pamela Broadbent ◽  
Helen Reynolds ◽  
Baldeep Kular ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Glutathione Reductase
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