A Reevaluation of the Role of Arabidopsis NRT1.1 in High-Affinity Nitrate Transport

Glass, Anthony D. M.; Kotur, Zorica

doi:10.1104/pp.113.229161

Cited by 33 publications

(27 citation statements)

References 49 publications

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“…In NAR2.1 mutants, from which NRT2 (but not NPF) proteins are absent, 13 NO 3 – influx is approximately 4% of WT values. Hence, it is unlikely that the remaining 13 NO 3 – influx observed in nrt2.5 mutants receives a significant contribution from NPF6.3 activity (Glass & Kotur ).…”

Section: Discussionmentioning

confidence: 99%

A 150 kDa plasma membrane complex of AtNRT2.5 and AtNAR2.1 is the major contributor to constitutive high‐affinity nitrate influx in Arabidopsis thaliana

Kotur

Glass

2015

Plant Cell & Environment

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In plants that have been deprived of nitrate for a significant length of time, a constitutive high-affinity nitrate transport system (cHATS) is responsible for initial nitrate uptake. This absorbed nitrate leads to the induction of the major nitrate transporters and enzymes involved in nitrate assimilation. By use of (13) NO3 (-) influx measurements and Blue Native polyacrylamide gel electrophoresis we examined the role of AtNRT2.5 in cHATS in wild type (WT) and various T-DNA mutants of Arabidopsis thaliana. We demonstrate that AtNRT2.5 is predominantly expressed in roots of nitrate-deprived WT plants as a 150 kDa molecular complex with AtNAR2.1. This complex represents the major contributor to cHATS influx, which is reduced by 63% compared with WT in roots of Atnrt2.5 mutants. The remaining cHATS nitrate influx in these mutants is due to a residual contribution by the inducible high-affinity transporter encoded by AtNRT2.1/AtNAR2.1. Estimates of the kinetic properties of the NRT2.5 transporter reveal that its low Km for nitrate makes this transporter ideally suited to detect and respond to trace quantities of nitrate in the root environment.

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Section: Discussionmentioning

confidence: 99%

A 150 kDa plasma membrane complex of AtNRT2.5 and AtNAR2.1 is the major contributor to constitutive high‐affinity nitrate influx in Arabidopsis thaliana

Kotur

Glass

2015

Plant Cell & Environment

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“…The findings of Wang et al, [17] and Liu et al, [18] have shown that over 75% of high-affinity nitrate uptake in plants (calculated by subtracting the root nitrate uptake rate of nrt1.1 mutants from that of wild-type plants) was contributed by NRT1.1. However, several studies have questioned the contribution made by the NRT1.1 high-affinity function to nitrate uptake with low external nitrate concentrations [21,22]. However, several studies have questioned the contribution made by the NRT1.1 high-affinity function to nitrate uptake with low external nitrate concentrations [21,22].…”

Section: Nitrate (No àmentioning

confidence: 99%

A reevaluation of the contribution of NRT1.1 to nitrate uptake in Arabidopsis under low‐nitrate supply

Tian

Jin

2019

FEBS Letters

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NRT1.1 has been previously characterized as a dual‐affinity nitrate transporter in Arabidopsis, though several lines of evidence have raised questions regarding its high‐affinity function in nitrate uptake. Here, we show that the induction of NRT2.1‐ and NRT2.2‐mediated nitrate uptake interferes with measurements of the contribution of NRT1.1 to high‐affinity uptake using nrt1.1 mutants. Therefore, a nrt1.1/2.1/2.2 triple mutant was generated to reevaluate the role of NRT1.1 in high‐affinity nitrate uptake. This triple mutant has a lower rate of nitrate uptake than the nrt2.1/2.2 double mutant under low external nitrate supply, resulting in a lower growth rate than that of the double mutant. Therefore, we conclude that NRT1.1‐mediated high‐affinity nitrate uptake is necessary for plant growth under low‐nitrate conditions.

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“…So, to date, both studied nitrate transporters from M. truncatula, MtNPF6.8 and MtNPF1.7, can transport nitrate at low concentrations when expressed in heterologous transport system, without having a HATS activity in planta (Morère-Le Paven et al 2011; Bagchi et al 2012;Pellizzaro et al 2014). Interestingly, AtNPF6.3 of A. thaliana, known to be a dual-affinity nitrate transporter in oocytes, has been shown to be involved in HATS in planta (Wang et al 1998;Liu et al 1999;Ho et al 2009), although this is a matter of debate (Glass and Kotur 2013).…”

Section: Function Of Nitrate Transport In Legumes Role Of Transportermentioning

confidence: 99%

Nitrate transporters: an overview in legumes

Pellizzaro

Alibert

Planchet

et al. 2017

Planta

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Main conclusion The nitrate transporters, belonging to NPF and NRT2 families, play critical roles in nitrate signaling, root growth and nodule development in legumes.Nitrate plays an essential role during plant development as nutrient and also as signal molecule, in both cases working via the activity of nitrate transporters. To date, few studies on NRT2 or NPF nitrate transporters in legumes have been reported, and most of those concern Lotus japonicus and Medicago truncatula. A molecular characterization led to the identification of 4 putative LjNRT2 and 37 putative LjNPF gene sequences in L. japonicus. In M. truncatula, the NRT2 family is composed of 3 putative members. Using the new genome annotation of M. truncatula (Mt4.0), we identified, for this review, 97 putative MtNPF sequences, including 32 new sequences relative to previous studies. Functional characterization has been published for only two MtNPF genes, encoding nitrate transporters of M. truncatula. Both transporters have a role in root system development via abscisic acid signaling: MtNPF6.8 acts as a nitrate sensor during the cell elongation of the primary root, while MtNPF1.7 contributes to the cellular organization of the root tip and nodule formation. An in silico expression study of MtNPF genes confirmed that NPF genes are expressed in nodules, as previously shown for L. japonicus, suggesting a role for the corresponding proteins in nitrate transport, or signal perception in nodules. This review summarizes our knowledge of legume nitrate transporters and discusses new roles for these proteins based on recent discoveries.

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A Reevaluation of the Role of Arabidopsis NRT1.1 in High-Affinity Nitrate Transport

Cited by 33 publications

References 49 publications

A 150 kDa plasma membrane complex of AtNRT2.5 and AtNAR2.1 is the major contributor to constitutive high‐affinity nitrate influx in Arabidopsis thaliana

A 150 kDa plasma membrane complex of AtNRT2.5 and AtNAR2.1 is the major contributor to constitutive high‐affinity nitrate influx in Arabidopsis thaliana

A reevaluation of the contribution of NRT1.1 to nitrate uptake in Arabidopsis under low‐nitrate supply

Nitrate transporters: an overview in legumes

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