Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jul;123(1):e70289.
doi: 10.1111/tpj.70289.

Arabidopsis Vacuolar protein sorting 9a (VPS9a) is required for glutamine synthetase/glutamate synthase (GS/GOGAT) cycle and autophagy under nutrient starvation

Baiyang Yu  1   2   3 , Yanhui Zhou  2   4 , Yunfeng Shi  2 , Shengshu Wang  2   5 , Qing Pang  2   4 , Chao Yang  2   4 , Thomas Roitsch  3 , Weiming Hu  2 , Yizhou Wang  1 , Fen Liu  2
Affiliations

Arabidopsis Vacuolar protein sorting 9a (VPS9a) is required for glutamine synthetase/glutamate synthase (GS/GOGAT) cycle and autophagy under nutrient starvation

Baiyang Yu et al. Plant J. 2025 Jul.

Abstract

Plants have developed complex endomembrane systems in response to environmental challenges such as nutrient deficiency. This study focused on the role of Vacuolar protein sorting 9 (VPS9a), a key regulatory gene involved in the endosomal sorting process in Arabidopsis thaliana. Loss of VPS9a function results in stress-sensitive phenotypes under carbon and nitrogen starvation. First, we investigated the changes in the Glutamine Synthetase/Glutamate Synthase (GS/GOGAT) cycle under nitrogen starvation and conducted a co-expression network analysis based on transcriptomic profiles. These results indicate that the endocytic pathway and the majority of the degradation processes are related to GS and NADH-GOGAT activity. Genes related to autophagy and endocytic pathways showed diverse response trends in Col-0, vps9a-2, and 35S:VPS9a-GFP/vps9a-2. Several autophagy- and endocytosis-related genes, including Autophagy-related protein 1 (ATG1), Autophagy-related protein 8 (ATG8), Thylakoid lumen protein (TLP18.3), Autoinhibited Ca(2+)-ATPase, Isoform 4 (ACA4), MAP kinase 2 (AtMKK2), and Extensin 21 (EXT21), were identified as hub genes. Further, we found that the loss of VPS9a function leads to reduced accumulation of autophagic bodies and a marked decrease in ATG8a protein levels but does not affect autophagic flux or the accumulation of ATG8 with phosphatidylethanolamine (PE). Interestingly, VPS9a appears to exert differential effects on various ATG8 Homologs. In summary, our results established a connection between autophagy, endocytic pathways, and nitrogen metabolism processes, identifying key hub genes involved in these processes. Among these hub genes, VPS9a was found to affect ATG8a levels, suggesting that VPS9a selectively regulates specific ATG8 proteins involved in autophagic processes.

Keywords: autophagy; endocytosis; glutamine synthetase/glutamate synthase (GS/GOGAT) cycle; nutrient deprivation; vacuolar protein sorting 9 (VPS9a).

PubMed Disclaimer

Similar articles

See all similar articles

References

    1. Aniento, F., de Medina, S., Hernandez, V., Dagdas, Y., Rojas‐Pierce, M. & Russinova, E. (2022) Molecular mechanisms of endomembrane trafficking in plants. Plant Cell, 34, 146–173.
    1. Balotf, S., Kavoosi, G. & Kholdebarin, B. (2016) Nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate synthase expression and activity in response to different nitrogen sources in nitrogen‐starved wheat seedlings. Biotechnology and Applied Biochemistry, 63, 220–229.
    1. Baral, A., Irani, N.G., Fujimoto, M., Nakano, A., Mayor, S. & Mathew, M.K. (2015) Salt‐induced remodeling of spatially restricted clathrin‐independent endocytic pathways in Arabidopsis root. Plant Cell, 27, 1297–1315.
    1. Barneix, A.J., James, D.M., Watson, E.F. & Hewitt, E.J. (1984) Some effects of nitrate abundance and starvation on metabolism and accumulation of nitrogen in barley (Hordeum vulgare L. cv Sonja). Planta, 162, 469–476.
    1. Boura, E., Rozycki, B., Herrick, D.Z., Chung, H.S., Vecer, J., Eaton, W.A. et al. (2011) Solution structure of the ESCRT‐I complex by small‐angle X‐ray scattering, EPR, and FRET spectroscopy. Proceedings of the National Academy of Sciences of the United States of America, 108, 9437–9442.

MeSH terms

LinkOut - more resources