Exogenous γ-aminobutyric acid (GABA) alleviates nitrogen deficiency by mediating nitrate uptake and assimilation in Andrographis paniculata seedlings.
Plant Physiol Biochem
; 198: 107700, 2023 May.
Article
em En
| MEDLINE
| ID: mdl-37086691
ABSTRACT
γ-Aminobutyric acid (GABA) plays significant metabolic and signaling roles in plant stress responses. Recent studies have proposed that GABA alleviates plant nitrogen (N) deficient stress; however, the mechanism by which GABA mediates plant N deficiency adaptation remains not yet well understood. Herein we found in a medicinal plant Andrographis paniculata that 5 mmol L-1 exogenous GABA promoted plant growth under N deficient (1 mmol L-1 NO3-) condition, with remarkably increments in total N and NO3- concentrations in plants. GABA increased N assimilation and protein synthesis by up-regulating the activities and expression of N metabolic enzymes. GABA also increased the accumulation of α-ketoglutarate and malate, which could facilitate the assimilation of NO3-. Inhibition of NR by Na2WO4 counteracted the promoting effects of GABA on plant growth, and the effects of GABA were not affected by L-DABA and 3-MP, the inhibitors of GABA transaminase (GABA-T) and glutamate decarboxylase (GAD), respectively. These results suggested that the nutritional role of GABA was excluded in promoting plant growth under low N condition. The results of 15N isotopic tracing and NRTs transcription indicated that exogenous GABA could up-regulate NRT2.4 and NRT3.2 to increase plant NO3- uptake under N deficient condition. Interestingly, primidone, an inhibitor of GABA receptor, impeded the effects of GABA on plant growth and N accumulation. Thus, our results revealed that exogenous GABA acted as a signal to up-regulate NRTs via its receptor to increase NO3- uptake, and subsequently promoted NO3- assimilation to alleviate N deficiency in A. paniculata.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Plântula
/
Nitratos
Idioma:
En
Revista:
Plant Physiol Biochem
Ano de publicação:
2023
Tipo de documento:
Article