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<p>Ascorbic acid, the most abundant soluble antioxidant, and the phytohormone abscisic acid (ABA) are major players in the signalling networks that allow plants to acclimate to challenging environments. In fact, the gene expression of a key enzyme in ascorbic acid synthesis is regulated by transcriptional factors linked to ABA metabolism and environmental factors. In this work we hypothesized that ABA regulates ascorbic acid accumulation in leaves of <i>Arabidopsis thaliana</i> (L.) Heynh rosettes and modulates its concentration responding to the incident irradiance. Mutant genotypes affected in ABA synthesis (<i>aba1-6</i>, <i>aba2-1</i> and <i>aba3-1</i>) or sensitivity (<i>abi2-1</i>) were used. Five-week-old rosettes were treated with increased irradiance and ABA (10 and 100&#xa0;μM) for 48&#xa0;h. Mutant genotypes exhibited higher leaf ascorbic acid concentration (compared to wild-type) at basal irradiance, which decreased with the application of exogenous ABA. On the other hand, the typical increase in foliar ascorbic acid concentration in response to increase in incident irradiance observed in the wild type was markedly attenuated in the deficient mutants and partially restored with exogenous ABA treatment in <i>aba2-1</i> and <i>aba3-1</i> genotypes. The results suggest that ABA negatively modulates the accumulation of ascorbic acid in Arabidopsis leaf tissues but it could positively modulate the increase in leaf ascorbic acid concentration in response to increased irradiance affecting crucial points of its synthesis pathway such as concentration of precursors (soluble sugars), gene expression and activity of ascorbic acid synthesis enzymes and respiration (which is a critical process that regulates ascorbic acid synthesis in mitochondria).</p>

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Involvement of ABA in ascorbate synthesis and accumulation in leaves

  • 期刊论文

  • 发表日期：

    2025年10月11日

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  • María Eugenia Senn,
  • Luis Miguel Mazorra Morales,
  • Gustavo Esteban Gergoff Grozeff,
  • Andrea Galatro,
  • Kátia Daniella da Cruz Saraiva,
  • Clesivan Pereira dos Santos,
  • José Hélio Costa,
  • Jurandi Gonçalves de Oliveira,
  • Carlos Guillermo Bartoli

摘要

Ascorbic acid, the most abundant soluble antioxidant, and the phytohormone abscisic acid (ABA) are major players in the signalling networks that allow plants to acclimate to challenging environments. In fact, the gene expression of a key enzyme in ascorbic acid synthesis is regulated by transcriptional factors linked to ABA metabolism and environmental factors. In this work we hypothesized that ABA regulates ascorbic acid accumulation in leaves of Arabidopsis thaliana (L.) Heynh rosettes and modulates its concentration responding to the incident irradiance. Mutant genotypes affected in ABA synthesis (aba1-6, aba2-1 and aba3-1) or sensitivity (abi2-1) were used. Five-week-old rosettes were treated with increased irradiance and ABA (10 and 100 μM) for 48 h. Mutant genotypes exhibited higher leaf ascorbic acid concentration (compared to wild-type) at basal irradiance, which decreased with the application of exogenous ABA. On the other hand, the typical increase in foliar ascorbic acid concentration in response to increase in incident irradiance observed in the wild type was markedly attenuated in the deficient mutants and partially restored with exogenous ABA treatment in aba2-1 and aba3-1 genotypes. The results suggest that ABA negatively modulates the accumulation of ascorbic acid in Arabidopsis leaf tissues but it could positively modulate the increase in leaf ascorbic acid concentration in response to increased irradiance affecting crucial points of its synthesis pathway such as concentration of precursors (soluble sugars), gene expression and activity of ascorbic acid synthesis enzymes and respiration (which is a critical process that regulates ascorbic acid synthesis in mitochondria).