Prolonged dark period modulates the oxidative burst and enzymatic antioxidant systems in the leaves of salicylic acid-treated tomato

Péter Poór, Zoltán Takács, Krisztina Bela, Zalán Czékus, Gabriella Szalai, Irma Tari

Research output: Contribution to journalArticle

13 Citations (Scopus)


Salicylic acid (SA) is an important plant growth regulator playing a role in the hypersensitive reaction (HR) and the induction of systemic acquired resistance. Since the SA-mediated signalling pathways and the formation of reactive oxygen species (ROS) are light-dependent, the time- and concentration-specific induction of oxidative stress was investigated in leaves of tomato plants kept under light and dark conditions after treatments with 0.1 mM and 1 mM SA. The application of exogenous SA induced early superoxide- and H2O2 production in the leaves, which was different in the absence or presence of light and showed time- and concentration-dependent changes. 1 mM SA, which induced HR-like cell death resulted in two peaks in the H2O2 production in the light but the first, priming peak was not detected in the dark. Unlike 0.1 mM SA, 1 mM SA application induced NADPH oxidase activity leading to increased superoxide production in the first hours of SA treatments in the light. Moreover, SA treatments inhibited catalase (CAT) activity and caused a transient decline in ascorbate peroxidase (APX), the two main enzymes responsible for H2O2 degradation, which led to a fast H2O2 burst in the light. Their activity as well as the expression of some isoenzymes of SOD and APX increased only from the 12th h in the illuminated samples. The activity of NADPH oxidase and expression SlRBOH1 gene encoding a NADPH oxidase subunit was much lower in the dark. In spite of low CAT and APX activity after SA treatments in the dark, the activation of guaiacol-dependent peroxidase (POD) could partially substitute H2O2 scavenging activity of these enzymes in the dark, which reduced the ROS burst and development of lesion formation in the leaves.

Original languageEnglish
Pages (from-to)216-226
Number of pages11
JournalJournal of Plant Physiology
Publication statusPublished - Jun 1 2017


  • Antioxidant enzymes
  • NADPH oxidase
  • Prolonged dark period
  • Salicylic acid
  • Tomato

ASJC Scopus subject areas

  • Physiology
  • Agronomy and Crop Science
  • Plant Science

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