RRC ID 68948
Author Hachiya T, Inaba J, Wakazaki M, Sato M, Toyooka K, Miyagi A, Kawai-Yamada M, Sugiura D, Nakagawa T, Kiba T, Gojon A, Sakakibara H.
Title Excessive ammonium assimilation by plastidic glutamine synthetase causes ammonium toxicity in Arabidopsis thaliana.
Journal Nat Commun
Abstract Plants use nitrate, ammonium, and organic nitrogen in the soil as nitrogen sources. Since the elevated CO2 environment predicted for the near future will reduce nitrate utilization by C3 species, ammonium is attracting great interest. However, abundant ammonium nutrition impairs growth, i.e., ammonium toxicity, the primary cause of which remains to be determined. Here, we show that ammonium assimilation by GLUTAMINE SYNTHETASE 2 (GLN2) localized in the plastid rather than ammonium accumulation is a primary cause for toxicity, which challenges the textbook knowledge. With exposure to toxic levels of ammonium, the shoot GLN2 reaction produced an abundance of protons within cells, thereby elevating shoot acidity and stimulating expression of acidic stress-responsive genes. Application of an alkaline ammonia solution to the ammonium medium efficiently alleviated the ammonium toxicity with a concomitant reduction in shoot acidity. Consequently, we conclude that a primary cause of ammonium toxicity is acidic stress.
Volume 12(1)
Pages 4944
Published 2021-8-16
DOI 10.1038/s41467-021-25238-7
PII 10.1038/s41467-021-25238-7
PMID 34400629
PMC PMC8367978
MeSH Amino Acids Ammonium Compounds / metabolism* Ammonium Compounds / toxicity* Arabidopsis / drug effects* Arabidopsis / genetics Arabidopsis / metabolism* Arabidopsis Proteins / metabolism Glutamate-Ammonia Ligase / drug effects Glutamate-Ammonia Ligase / genetics Glutamate-Ammonia Ligase / metabolism* Nitrates / metabolism Nitrogen / metabolism Plant Shoots / metabolism Plastids / metabolism*
IF 12.121
Arabidopsis / Cultured plant cells, genes psi00011 pss10001 pss10002 pss10003 pss10004 pss10005 pss10006 pss10007 pss10008 pss10009 pss10010 pss10011 pss10012 pss10013 pss10014 pss10015 pss10016 pss10017 pss10018 pss10019 pss10020 pss10021