Three polarly localized ammonium transporter 1 members are cooperatively responsible for ammonium uptake in rice under low ammonium condition

2021 ◽  
Author(s):  
Noriyuki Konishi ◽  
Jian Feng Ma
Keyword(s):  
Ammonium Transporter ◽  
Ammonium Uptake

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 Differential Expression of Aspergillus nidulans Ammonium Permease Genes Is Regulated by GATA Transcription Factor AreA

2006 ◽  
Vol 5 (2) ◽  
pp. 226-237 ◽  
Author(s):  
Brendon J. Monahan ◽  
Marion C. Askin ◽  
Michael J. Hynes ◽  
Meryl A. Davis
Keyword(s):  
Aspergillus Nidulans ◽  
Sufficient Conditions ◽  
Optimal Growth ◽  
Ammonium Transporter ◽  
Ammonium Uptake ◽  
Ammonium Transport ◽  
Gata Factor ◽  
High Affinity ◽  
Gata Transcription Factor ◽  
Nitrogen Conditions

ABSTRACT The movement of ammonium across biological membranes is mediated in both prokaryotes and eukaryotes by ammonium transport proteins (AMT/MEP) that constitute a family of related sequences. We have previously identified two ammonium permeases in Aspergillus nidulans, encoded by the meaA and mepA genes. Here we show that meaA is expressed in the presence of ammonium, consistent with the function of MeaA as the main ammonium transporter required for optimal growth on ammonium as a nitrogen source. In contrast, mepA, which encodes a high-affinity ammonium permease, is expressed only under nitrogen-limiting or starvation conditions. We have identified two additional AMT/MEP-like genes in A. nidulans, namely, mepB, which encodes a second high-affinity ammonium transporter expressed only in response to complete nitrogen starvation, and mepC, which is expressed at low levels under all nitrogen conditions. The MepC gene product is more divergent than the other A. nidulans AMT/MEP proteins and is not thought to significantly contribute to ammonium uptake under normal conditions. Remarkably, the expression of each AMT/MEP gene under all nitrogen conditions is regulated by the global nitrogen regulatory GATA factor AreA. Therefore, AreA is also active under nitrogen-sufficient conditions, along with its established role as a transcriptional activator in response to nitrogen limitation.

scholarly journals CALCIUM-DEPENDENT PROTEIN KINASE 32-mediated phosphorylation is essential for the ammonium transport activity of AMT1;1 in Arabidopsis roots

2020 ◽  
Vol 71 (16) ◽  
pp. 5087-5097
Author(s):  
De-Bin Qin ◽  
Meng-Yuan Liu ◽  
Lixing Yuan ◽  
Yun Zhu ◽  
Xi-Dong Li ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Ammonium Transporter ◽  
Ammonium Uptake ◽  
Ammonium Transport ◽  
Toxicity Screening ◽  
Plant Signaling ◽  
Transport Activity ◽  
Calcium Dependent ◽  
Positive Regulator ◽  
Dependent Protein

Abstract Protein kinase-mediated phosphorylation modulates the absorption of many nutrients in plants. CALCIUM-DEPENDENT PROTEIN KINASES (CPKs) are key players in plant signaling to translate calcium signals into diverse physiological responses. However, the regulatory role of CPKs in ammonium uptake remains largely unknown. Here, using methylammonium (MeA) toxicity screening, CPK32 was identified as a positive regulator of ammonium uptake in roots. CPK32 specifically interacted with AMMONIUM TRANSPORTER 1;1 (AMT1;1) and phosphorylated AMT1;1 at the non-conserved serine residue Ser450 in the C-terminal domain. Functional analysis in Xenopus oocytes showed that co-expression of CPK32 and AMT1;1 significantly enhanced the AMT1;1-mediated inward ammonium currents. In transgenic plants, the phosphomimic variant AMT1;1S450E, but not the non-phosphorylatable variant AMT1;1S450A, fully complemented the MeA insensitivity and restored high-affinity 15NH4+ uptake in both amt1;1 and cpk32 mutants. Moreover, in the CPK32 knockout background, AMT1;1 lost its ammonium transport activity entirely. These results indicate that CPK32 is a crucial positive regulator of ammonium uptake in roots and the ammonium transport activity of AMT1;1 is dependent on CPK32-mediated phosphorylation.

scholarly journals NH4+-mediated Protein Phosphorylation in Rice Roots

2015 ◽  
Vol 57 (2) ◽  
pp. 38-48 ◽  
Author(s):  
Xiao Feng Zhu ◽  
Wan Hui Cai ◽  
Jin Hee Jung ◽  
Yuan Hu Xuan
Keyword(s):  
Growth And Development ◽  
Biochemical Analysis ◽  
Underlying Mechanism ◽  
Ammonium Transporter ◽  
Ammonium Uptake ◽  
Plant Growth And Development ◽  
Rice Roots ◽  
N Source ◽  
Phosphorylation Level ◽  
Important Evidence

Abstract NH4+ is an important N-source which regulates plant growth and development. However, the underlying mechanism of NH4+ uptake and its-mediated signaling is poorly understood. Here, we performed phosphoproteomic studies using the titanium dioxide (TiO2)-mediated phosphopeptides collection method together with LC-MS analysis. The results indicated that phosphorylation levels of 23 and 43 peptides/proteins involved in diverse aspects, including metabolism, transport and signaling pathway, were decreased and increased respectively after NH4+ treatment in rice roots. Among 23 proteins detected, IDD10, a key transcription factor in ammonium signaling, was identified to reduce phosphorylation level of S313 residue. Further biochemical analysis using IDD10-GFP transgenic plants and immunoprecipitation assay confirmed that NH4+ supply reduces IDD10 phosphorylation level. Phosphorylation of ammonium transporter 1;1 (AMT1;1) was increased upon NH4+ treatment. Interestingly, phosphorylation of T446, a rice specific residue against Arabidopsis was identified. It was also established that phosphorylation of T452 is conserved with T460 of Arabidopsis AMT1;1. Yeast complementation assay with transformation of phosphomimic forms of AMT1;1 (T446/D and T452/D) into 31019b strain revealed that phosphorylation at T446 and T452 residues abolished AMT1;1 activity, while their plasma membrane localization was not changed. Our analyses show that many proteins were phosphorylated or dephosphorylated by NH4+ that may provide important evidence for studying ammonium uptake and its mediated signaling by which rice growth and development are regulated.

PREFERENTIAL AMMONIUM UPTAKE DURING GROWTH CYCLE AND IDENTIFICATION OF AMMONIUM TRANSPORTER GENES IN YOUNG PEAR TREES

2011 ◽  
Vol 34 (6) ◽  
pp. 798-814 ◽  
Author(s):  
Mariana Mota ◽  
Cláudia B. Neto ◽  
António A. Monteiro ◽  
Cristina M. Oliveira
Keyword(s):  
Growth Cycle ◽  
Ammonium Transporter ◽  
Ammonium Uptake ◽  
Pear Trees

scholarly journals (Methyl)ammonium Transport in the Nitrogen-Fixing Bacterium Azospirillum brasilense

1998 ◽  
Vol 180 (10) ◽  
pp. 2652-2659 ◽  
Author(s):  
Anne Van Dommelen ◽  
Veerle Keijers ◽  
Jos Vanderleyden ◽  
Miklos de Zamaroczy
Keyword(s):  
Azospirillum Brasilense ◽  
Transport Mechanism ◽  
Integral Membrane Protein ◽  
Regulatory Proteins ◽  
Ammonium Transporter ◽  
Ammonium Uptake ◽  
Ammonium Transport ◽  
Wild Type ◽  
Protein Nitrogen ◽  
Low Concentrations

ABSTRACT An ammonium transporter of Azospirillum brasilense was characterized. In contrast to most previously reported putative prokaryotic NH4 + transporter genes, A. brasilense amtB is not part of an operon withglnB or glnZ which, in A. brasilense, encode nitrogen regulatory proteins PIIand PZ, respectively. Sequence analysis predicts the presence of 12 transmembrane domains in the deduced AmtB protein and classifies AmtB as an integral membrane protein. Nitrogen regulates the transcription of the amtB gene in A. brasilense by the Ntr system. amtB is the first gene identified in A. brasilense whose expression is regulated by NtrC. The observation that ammonium uptake is still possible in mutants lacking the AmtB protein suggests the presence of a second NH4 + transport mechanism. Growth ofamtB mutants at low ammonium concentrations is reduced compared to that of the wild type. This suggests that AmtB has a role in scavenging ammonium at low concentrations.

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.

Sign in / Sign up

Export Citation Format

Share Document