Abstract
The photorespiratory intermediate glycerate is known to be shuttled between the peroxisome and chloroplast. Here, localization of NPF8.4 in the tonoplast, together with the reduced vacuolar glycerate content displayed by an npf8.4 mutant and the glycerate efflux activity detected in an oocyte expression system, identifies NPF8.4 as a tonoplast glycerate influx transporter. Our study shows that expression of NPF8.4 and most photorespiration-associated genes, as well as the photorespiration rate, is upregulated in response to short-term nitrogen (N) depletion. We report growth retardation and early senescence phenotypes for npf8.4 mutants specifically upon N depletion, suggesting that the NPF8.4-mediated regulatory pathway for sequestering the photorespiratory carbon intermediate glycerate in vacuoles is important to alleviate the impact of an increased C/N ratio under N deficiency. Thus, our study of NPF8.4 reveals a novel role for photorespiration in N flux to cope with short-term N depletion.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 digital issues and online access to articles
$119.00 per year
only $9.92 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout








Data availability
All data supporting the findings of this study are available within the article, Extended Data Figs. 1–8 and the Supplementary Information, or from the corresponding author upon reasonable request. The RNA-seq raw data are deposited in the NCBI Gene Expression Omnibus under GEO accession number GSE224214. TAIR 10 Genome (www.arabidopsis.org) and Araport11 (www.araport.org) were used as references to identify potential transcripts. Source data are provided with this paper.
References
Strahm, B. D. & Harrison, R. B. Nitrate sorption in a variable-charge forest soil of the Pacific Northwest. Soil Sci. 171, 313–321 (2006).
Johnson, P. T. et al. Aquatic eutrophication promotes pathogenic infection in amphibians. Proc. Natl Acad. Sci. USA 104, 15781–15786 (2007).
Gruber, B. D., Giehl, R. F., Friedel, S. & von Wiren, N. Plasticity of the Arabidopsis root system under nutrient deficiencies. Plant Physiol. 163, 161–179 (2013).
Von Wiren, N. et al. Differential regulation of three functional ammonium transporter genes by nitrogen in root hairs and by light in leaves of tomato. Plant J. 21, 167–175 (2000).
Kiba, T. et al. The Arabidopsis nitrate transporter NRT2.4 plays a double role in roots and shoots of nitrogen-starved plants. Plant Cell. 24, 245–258 (2012).
Fan, S. C., Lin, C. S., Hsu, P. K., Lin, S. H. & Tsay, Y. F. The Arabidopsis nitrate transporter NRT1.7, expressed in phloem, is responsible for source-to-sink remobilization of nitrate. Plant Cell. 21, 2750–2761 (2009).
Avin-Wittenberg, T. et al. Autophagy-related approaches for improving nutrient use efficiency and crop yield protection. J. Exp. Bot. 69, 1335–1353 (2018).
Tegeder, M. Transporters involved in source to sink partitioning of amino acids and ureides: opportunities for crop improvement. J. Exp. Bot. 65, 1865–1878 (2014).
Nunes-Nesi, A., Fernie, A. R. & Stitt, M. Metabolic and signaling aspects underpinning the regulation of plant carbon nitrogen interactions. Mol. Plant. 3, 973–996 (2010).
Zhu, X.-G., Long, S. P. & Ort, D. R. What is the maximum efficiency with which photosynthesis can convert solar energy into biomass? Curr. Opin. Biotechnol. 19, 153–159 (2008).
Ferreira, S., Moreira, E., Amorim, I., Santos, C. & Melo, P. Arabidopsis thaliana mutants devoid of chloroplast glutamine synthetase (GS2) have non-lethal phenotype under photorespiratory conditions. Plant Physiol. Biochem. 144, 365–374 (2019).
Marino, D., Cañas, R. A. & Betti, M. Is plastidic glutamine synthetase essential for C3 plants? A tale of photorespiratory mutants, ammonium tolerance and conifers. New Phytol. 234, 1559–1565 (2022).
Rachmilevitch, S., Cousins, A. B. & Bloom, A. J. Nitrate assimilation in plant shoots depends on photorespiration. Proc. Natl Acad. Sci. USA 101, 11506–11510 (2004).
Bloom, A. J. & Lancaster, K. M. Manganese binding to Rubisco could drive a photorespiratory pathway that increases the energy efficiency of photosynthesis. Nat. Plants 4, 414–422 (2018).
Krämer, K., Kepp, G., Brock, J., Stutz, S. & Heyer, A. G. Acclimation to elevated CO2 affects the C/N balance by reducing de novo N‐assimilation. Physiol. Plant. 174, e13615 (2022).
Bloom, A. J., Kasemsap, P. & Rubio‐Asensio, J. S. Rising atmospheric CO2 concentration inhibits nitrate assimilation in shoots but enhances it in roots of C3 plants. Physiol. Plant. 168, 963–972 (2020).
Pick, T. R. et al. PLGG1, a plastidic glycolate glycerate transporter, is required for photorespiration and defines a unique class of metabolite transporters. Proc. Natl Acad. Sci. USA 110, 3185–3190 (2013).
South, P. F. et al. Bile acid sodium symporter BASS6 can transport glycolate and is involved in photorespiratory metabolism in Arabidopsis thaliana. Plant Cell. 29, 808–823 (2017).
Enser, U. & Heber, U. Metabolic regulation by pH gradients. Inhibition of photosynthesis by indirect proton transfer across the chloroplast envelope. Biochim. Biophys. Acta 592, 577–591 (1980).
Wang, Y.-Y., Cheng, Y.-H., Chen, K.-E. & Tsay, Y.-F. Nitrate transport, signaling, and use efficiency. Annu. Rev. Plant Biol. 69, 85–122 (2018).
Payne, R. M. E. et al. An NPF transporter exports a central monoterpene indole alkaloid intermediate from the vacuole. Nat. Plants 3, 16208 (2017).
Chao, Z. F. et al. NPF transporters in synaptic-like vesicles control delivery of iron and copper to seeds. Sci. Adv. 7, eabh2450 (2021).
Kazachkova, Y. et al. The GORKY glycoalkaloid transporter is indispensable for preventing tomato bitterness. Nat. Plants 7, 468–480 (2021).
Michniewicz, M. et al. TRANSPORTER OF IBA1 links auxin and cytokinin to influence root architecture. Dev. Cell 50, 599–609 e594 (2019).
Komarova, N. Y. et al. AtPTR1 and AtPTR5 transport dipeptides in planta. Plant Physiol. 148, 856–869 (2008).
Weichert, A. et al. AtPTR4 and AtPTR6 are differentially expressed, tonoplast-localized members of the peptide transporter/nitrate transporter 1 (PTR/NRT1) family. Planta 235, 311–323 (2012).
Zemach, A. et al. The Arabidopsis nucleosome remodeler DDM1 allows DNA methyltransferases to access H1-containing heterochromatin. Cell 153, 193–205 (2013).
Schmitz, R. J. et al. Patterns of population epigenomic diversity. Nature 495, 193–198 (2013).
Koeslin-Findeklee, F. et al. Transcriptomic analysis of nitrogen starvation- and cultivar-specific leaf senescence in winter oilseed rape (Brassica napus L.). Plant Sci. 233, 174–185 (2015).
Li, Y., Xu, J., Haq, N. U., Zhang, H. & Zhu, X.-G. Was low CO2 a driving force of C4 evolution: Arabidopsis responses to long-term low CO2 stress. J. Exp. Bot. 65, 3657–3667 (2014).
Willems, P. et al. The ROS wheel: refining ROS transcriptional footprints. Plant Physiol. 171, 1720–1733 (2016).
Husted, S., Mattsson, M., Mollers, C., Wallbraun, M. & Schjoerring, J. K. Photorespiratory NH(4)(+) production in leaves of wild-type and glutamine synthetase 2 antisense oilseed rape. Plant Physiol. 130, 989–998 (2002).
Miyazawa, S., Hayashi, K., Nakamura, H., Hasegawa, T. & Miyao, M. Elevated CO2 decreases the photorespiratory NH3 production but does not decrease the NH3 compensation point in rice leaves. Plant Cell Physiol. 55, 1582–1591 (2014).
Lee, K. T., Chung, Y. H. & Hsieh, M. H. The Arabidopsis glutamine synthetase2 mutants (gln2-1 and gln2-2) do not have abnormal phenotypes. Plant Physiol. 189, 1906–1910 (2022).
Quesada, A., Gómez-Garcı́a, I. & Fernández, E. Involvement of chloroplast and mitochondria redox valves in nitrate assimilation. Trends Plant Sci. 5, 463–464 (2000).
Boldt, R. et al. d-GLYCERATE 3-KINASE, the last unknown enzyme in the photorespiratory cycle in Arabidopsis, belongs to a novel kinase family. Plant Cell. 17, 2413–2420 (2005).
Timm, S. et al. A cytosolic pathway for the conversion of hydroxypyruvate to glycerate during photorespiration in Arabidopsis. Plant Cell. 20, 2848–2859 (2008).
Timm, S. et al. High-to-low CO2 acclimation reveals plasticity of the photorespiratory pathway and indicates regulatory links to cellular metabolism of Arabidopsis. PLoS ONE 7, e42809 (2012).
Keller, R., Ziegler, C. & Schneider, D. When two turn into one: evolution of membrane transporters from half modules. Biol. Chem. 395, 1379–1388 (2014).
Xuan, Y. H. et al. Functional role of oligomerization for bacterial and plant SWEET sugar transporter family. Proc. Natl Acad. Sci USA 110, E3685–E3694 (2013).
Saier, M. H. Transport protein evolution deduced from analysis of sequence, topology and structure. Curr. Opin. Struct. Biol. 38, 9–17 (2016).
Youkharibache, P., Tran, A. & Abrol, R. Pseudo-symmetric assembly of protodomains as a common denominator in the evolution of polytopic helical membrane proteins. J. Mol. Evol. 88, 319–344 (2020).
Chen, H. Y. et al. Potential transceptor AtNRT1.13 modulates shoot architecture and flowering time in a nitrate-dependent manner. Plant Cell. 33, 1492–1505 (2021).
Lee, Y. J., Kim, D. H., Kim, Y.-W. & Hwang, I. Identification of a signal that distinguishes between the chloroplast outer envelope membrane and the endomembrane system in vivo. Plant Cell. 13, 2175–2190 (2001).
Sheen, J. Signal transduction in maize and Arabidopsis mesophyll protoplasts. Plant Physiol. 127, 1466–1475 (2001).
Curtis, M. D. & Grossniklaus, U. A gateway cloning vector set for high-throughput functional analysis of genes in planta. Plant Physiol. 133, 462–469 (2003).
Fiehn, O. et al. Quality control for plant metabolomics: reporting MSI-compliant studies. Plant J. 53, 691–704 (2008).
Rentsch, D. & Martinoia, E. Citrate transport into barley mesophyll vacuoles? Comparison with malate-uptake activity. Planta 184, 532–537 (1991).
Leigh, R. A. & Walker, R. R. ATPase and acid phosphatase activities associated with vacuoles isolated from storage roots of red beet (Beta vulgaris L.). Planta 150, 222–229 (1980).
Ohnishi, M. et al. Molecular components of Arabidopsis intact vacuoles clarified with metabolomic and proteomic analyses. Plant Cell Physiol. 59, 1353–1362 (2018).
Meng, X. et al. Simultaneous 3-nitrophenylhydrazine derivatization strategy of carbonyl, carboxyl and phosphoryl submetabolome for LC-MS/MS-based targeted metabolomics with improved sensitivity and coverage. Anal. Chem. 93, 10075–10083 (2021).
Hsu, P. K. & Tsay, Y. F. Two phloem nitrate transporters, NRT1.11 and NRT1.12, are important for redistributing xylem-borne nitrate to enhance plant growth. Plant Physiol. 163, 844–856 (2013).
Sharkey, T. D. Estimating the rate of photorespiration in leaves. Physiol. Plant. 73, 147–152 (1988).
Wang, X., Lewis, J. D., Tissue, D. T., Seemann, J. R. & Griffin, K. L. Effects of elevated atmospheric CO2 concentration on leaf dark respiration of Xanthium strumarium in light and in darkness. Proc. Natl Acad. Sci. USA 98, 2479–2484 (2001).
Walker, B., Ariza, L. S., Kaines, S., Badger, M. R. & Cousins, A. B. Temperature response of in vivo Rubisco kinetics and mesophyll conductance in Arabidopsis thaliana: comparisons to Nicotiana tabacum. Plant Cell Environ. 36, 2108–2119 (2013).
Novitskaya, L., Trevanion, S. J., Driscoll, S., Foyer, C. H. & Noctor, G. How does photorespiration modulate leaf amino acid contents? A dual approach through modelling and metabolite analysis. Plant Cell Environ. 25, 821–835 (2002).
Chen, K. E., Chen, H. Y., Tseng, C. S. & Tsay, Y. F. Improving nitrogen use efficiency by manipulating nitrate remobilization in plants. Nat. Plants 6, 1126–1135 (2020).
Thayer, J. R. & Huffaker, R. C. Determination of nitrate and nitrite by high-pressure liquid chromatography: comparison with other methods for nitrate determination. Anal. Biochem. 102, 110–119 (1980).
Acknowledgements
We thank S.-H. Lin in our lab for assistance with the 15N analysis; S.-P. Li and S.-M. Huang from our Confocal Microscope Facility for assistance with the acquisition of confocal microscopy images; S.-Y. Tung and C.-I. Yu from our Genomics Core facility and H.-N. Lin from our Bioinformatics Core facility for help with the RNA-seq experiment and analysis; and J. O’Brien for English editing. We thank C.-Y. Lin, C.-Y. Ting and T.-H. Chang from the Metabolomics Core Facility of the Agricultural Biotechnology Research Center for GC/MS and UPLC–MS/MS parameter optimization and the mass spectrometry analysis and the Plant Tech Core Facility in the Agricultural Biotechnology Research Center for generating the CRISPR constructs. This work was supported by grants from National Science and Technology Council (MOST 108-2311-B-001-006-MY3; MOST 111-2326-B-001-010-), an investigation award from Academia Sinica and a grant from the Institute of Molecular Biology, Academia Sinica, Taiwan.
Author information
Authors and Affiliations
Contributions
Y.-C.L. and Y.-F.T. conceived and designed the project. Y.-C.L. performed the experiments and analysed the data. Y.-C.L. and Y.-F.T. wrote the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature Plants thanks Arnd Heyer, Xinxiang Peng and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data
Extended Data Fig. 1 Diurnal expression pattern of NPF8.4 under normal light or elevated light conditions.
Transcript levels of NPF8.4a (a), NPF8.4b (b), and NPF8.4c (c) were determined by RT-qPCR amplicons against the specific region marked in Fig. 1a. Plants were grown hydroponically with 5 mM KNO3 for 15 days and then shifted to N-depleted medium for 2 days under normal light (100 μmol m–2 s–1) or elevated light (350 μmol m–2 s–1), with a 16-h-light/8-h dark cycle. Relative transcript levels on the second day of N depletion were determined by RT-qPCR using ACT2 as an internal control. Values represent mean ± SD for three biological repeats, with each repeat comprising five plants. Different letters represent significant differences based on one-way ANOVA (p < 0.0001) with Tukey’s HSD post hoc test (p ≤ 0.05) in a-c. Two-way ANOVA results are also shown in the top right corner (*p = 0.0019; **p = 0.0001; ***p < 0.0001 in (a), ***p < 0.0001 in (b), and **p = 0.0001; ***p < 0.0001 in (c).
Extended Data Fig. 2 Genomic PCR and RT-PCR analyses of npf8.4-1.
a. Genomic PCR. b. RT-PCR. Total RNA was extracted from the shoots and NPF8.4 expression was analyzed using primers F and R (see Supplementary Table 4). UBQ10, internal RT-PCR control. Positions of the primers F, R, and LB are shown in Fig. 4a. Similar results were observed for three independent experiments. Uncropped scans of gels are provided as Source Data Fig. 1.
Extended Data Fig. 3 The growth phenotypes of 15-day-old wild-type and the npf8.4-1 mutant shifted to N depletion for the indicated number of days.
a, Photos of wild-type and npf8.4-1 mutant in response to N depletion. b. Shoot dry weight of Col-0 and the npf8.4-1 mutant in response to N depletion. Values represent mean ± SD for three biological repeats. Plants were grown hydroponically with 5 mM KNO3 for 15 days and then transferred to N-depleted medium for the number of days indicated. Different letters represent significant differences based on one-way ANOVA (p < 0.0001) with Tukey’s HSD post hoc test (p ≤ 0.05). Two-way ANOVA results are also shown in the top right corner. ‘***’, p < 0.0001. Similar results were obtained from three independent experiments.
Extended Data Fig. 4 Protein expression levels in X. laevis oocytes.
Protein levels of NPF8.4a and NPF8.4b in water-, NPF8.4a- and NPF8.4b-injected oocytes were analyzed by hybridizing to anti-NPF8.4 antibodies. Similar results were observed for three independent experiments.
Extended Data Fig. 5 Metabolomics and RNAseq analysis reveal increased photorespiration flux in response to 2-day N depletion.
For ease of comparison, the gene expression levels shown in boxes have been normalized to the same gene in wild-type at day 0 (representing 1). Metabolite content shown in circles is normalized to the same metabolite in wild-type at day 0 (representing 100). Transcriptome fold-change and magnitude of metabolite accumulation are illustrated according to the color key at bottom. Thick red lines indicate reactions upregulated in response to 2-day N depletion. Glycerate is highlighted in yellow, and NH4+ is highlighted in cyan. ‘*’ represents a significant difference between wild-type and mutants in the metabolomics analysis (p ≤ 0.05; Student’s t-test). Boxes with a thick frame reflect significant differences in gene expression or metabolite content before and after N depletion (p ≤ 0.05; Student’s t-test). Plant growth conditions are the same as for those detailed in Supplementary Table 2. Data represent the mean values of three biological replicates, with each replicate consisting of 15 plants.
Extended Data Fig. 6 The growth retardation phenotype of the npf8.4 mutants under N deficiency can be rescued by elevated CO2 conditions when the photorespiration pathway is attenuated.
a, c, Photos of 16-day-old plants in response to N deficiency (a) or N sufficiency (c) under ambient CO2 (400 ppm) or high CO2 (900 ppm). b, d, Shoot dry weight of Col-0 and npf8.4 mutants in response to N deficiency (b) or N sufficiency (d) under ambient CO2 (400 ppm) or high CO2 (900 ppm). Plants were grown hydroponically with 5 mM KNO3 for 8 days and then kept under the same condition (5 KN) or shifted to N depletion (-N) for a further 8 days under ambient CO2 (400 ppm) or high CO2 (900 ppm), respectively. Values represent mean ± SD for four biological repeats. Different letters represent significant differences based on one-way ANOVA (p < 0.0001 in (b); p = 0.0001 in (d)) with Tukey’s HSD post hoc test (p ≤ 0.05). Two-way ANOVA results are also shown in the top right corner. ‘***’, p < 0.0001; ‘ns’, no significance. Similar results were obtained from two independent experiments.
Extended Data Fig. 7 Scatterplot of the C/N atom ratio v.s. fold-change in amino acids in response to 2-day N depletion.
Fold-changes in amino acids after 2 days of N depletion (D2) were calculated by normalizing to the same amino acid at day 0 (D0, representing 100%). Statistical significance of the linear relationship between the C/N atom ratio and fold-change in amino acids was calculated using the Pearson correlation coefficient (r = 0.76, p = 0.007).
Extended Data Fig. 8 Homo-oligomerization of NPF8.4b in a yeast-based split ubiquitin system.
a, An X-Gal filter assay and b, quantitative β-galactosidase measurements were performed using NPF8.4b-Cub-PLV as bait and NubG, NubI, or NubG-NPF8.4b as prey. The N-terminal part of wild-type ubiquitin (NubI) or of a mutant (NubG) that does not interact with the C-terminal part of ubiquitin was used as the positive and negative control, respectively. The data in (b) represent the mean ± SD from three biological repeats. Similar results were observed for three independent experiments.
Supplementary information
Supplementary Information
Supplementary Tables 1–4.
Source data
Source Data Fig. 1.
Unprocessed gels of Extended Data Fig. 2.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Lin, YC., Tsay, YF. Study of vacuole glycerate transporter NPF8.4 reveals a new role of photorespiration in C/N balance. Nat. Plants 9, 803–816 (2023). https://doi.org/10.1038/s41477-023-01392-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41477-023-01392-2