Original contribution
Hydrogen peroxide-mediated catalase gene expression in response to wounding

https://doi.org/10.1016/S0891-5849(00)00212-4Get rights and content

Abstract

The effect of wounding on catalase expression was examined in embryos and leaves of maize. All three Cat genes are upregulated in response to wounding in immature embryos. Cat expression also increased in response to jasmonic acid (JA), raising the possibility that JA and wounding may share a common signal transduction pathway in upregulating Cat mRNA in immature embryos. In young leaves, only Cat1 and Cat3 transcripts increase in response to wounding, but JA does not play a role. Cat1 and Cat3 transcript accumulation also increases in response to wounding in both wild-type and mutant leaves deficient in abscisic acid (ABA), implying that Cat1 and Cat3 induction in response to wounding is not mediated by ABA in leaves. Transient assays using the Cat1 promoter fused with the reporter gene Gus, showed that the DNA sequence motif responsible for Cat1 upregulation by wounding overlaps with the ABA-responsive element (ABRE, G-box) in the Cat1 promoter. The exact nature of the signals triggering the Cat responses to wounding is not clear at this point, but some evidence indicates that reactive oxygen species (ROS) play a role in this response. In fact, we have found that endogenous H2O2 levels increase in wounded leaves. Thus, wounding may indirectly induce the production of H2O2 in leaves, triggering the antioxidant response.

Introduction

Catalase (E.C.1.11.1.6 H2O2H2O2 oxidoreductase; CAT) is an iron porphyrin enzyme that catalyzes the dismutation of H2O2:H2O2 to water and dioxygen. CAT, along with hydroperoxidases and superoxide dismutases, serves as an efficient scavenger of ROS, preventing cellular damage. In maize, three catalase isozymes have been identified and characterized in various tissues [1]. CAT-1, CAT-2, and CAT-3 are encoded by the three unlinked structural genes Cat1, Cat2, and Cat3. The developmental expression pattern of each CAT is unique and complex. CAT-1 is the only catalase expressed in mature pollen and the immature milky endosperm. CAT-1 is also expressed in scutella in the early stages of kernel development, with highest activity levels in the late stages of kernel development. Upon imbibition and germination, CAT-1 is initially the only CAT isozyme expressed in the scutellum, but, as the embryo grows, CAT-1 diminishes and CAT-2 becomes the predominant isozyme, reaching an activity peak at about 4 dpi. In addition to developmental regulation, CAT expression is also influenced by many environmental factors such as light [2], plant hormones [3], ozone [4], temperature [5], xenobiotics [6], and hydrogen peroxide [7], underscoring the important protective roles of catalase in response to oxidative stress.

Environmental stress due to wounding greatly affects crop production. Plants respond quickly to wounding stress, such as physical injury and insect attack, by activating diverse genes that encode proteins involved in healing injured tissues. Some representative examples are the proteinase inhibitor genes, such as Pin2, that are transcriptionally activated by wounding [8]. A rapid increase in endogenous levels of ABA and JA occurs after wounding [9], and inhibitors of JA biosynthesis also inhibit the wound-induced expression of the proteinase inhibitor genes [10]. JA is regarded as one of the endogenous wound-induced signals involved in the expression of defensive genes, such as those for proteinase inhibitors. Other wound-inducible signaling molecules, such as systemin, oligogalacturonide, and ABA, have been shown to cause increased levels of endogenous JA [11]. ABA-deficient plants do not accumulate Pin2 mRNA upon wounding, indicating that ABA is required to function upstream of JA in the wound-induced signaling cascade [9], [12].

The carotenoid-deficient vp mutants of maize have great potential for providing information concerning the regulation of gene expression in response to ABA in both embryos and vegetative tissues [13]. A group of vp maize mutants are deficient in ABA (e.g., vp5) [12]. Seedlings rescued from vp5 kernels contain much less ABA (< 20%) than do wild-type seedlings, and the ABA concentration does not increase in response to water deficit [14].

In this paper, we demonstrate that each Cat gene responds differently to wounding in embryos and in leaves. In an effort to clarify the roles of JA and ABA, if any, in the maize Cat gene response to wounding in vegetative organs, we also examined the regulation of Cat gene expression in wild-type and vp5leaves subjected to wounding. The results presented here show that each Cat gene (Cat1, Cat2, and Cat3) responds differently to wounding in vp5 leaves. There is no change in Cat2 transcript accumulation in response to wounding. In contrast, the Cat1 and Cat3 transcripts increased dramatically in response to wounding in both wild type (Vp5/-) and mutant(vp5/vp5) leaves, suggesting that Cat1 and Cat3 expression in response to wounding may not be related to changes in endogenous ABA levels in leaves. Application of JA to leaves did not significantly induce Cat gene expression. Thus, an ABA-independent and JA-independent mechanism might be involved in Cat1 and Cat3 transcript accumulation in response to wounding in vegetative tissues. We have found that production of H2O2 is elevated in response to wounding. Thus, ROS is a likely mediator for wounding induced Cat gene expression.

Section snippets

Plant materials

The maize lines M1A4 (Vp5/-) and W64A were used in these studies. The maize vp5 mutant contains lowered amounts of ABA, resulting in precocious germination on the ear. The vp kernels can be distinguished from wild-type kernels early in development based on endosperm and embryo color. The vp5 mutation in M1A4 interrupts ABA biosynthesis early in the biosynthetic pathway [15]. Homozygous recessive kernels (vp5/vp5) lack carotenoids, resulting in white endosperm and embryos, easily distinguished

Cat gene expression in response to wounding and JA in 28 dpp developing embryos

Immature embryos were used to examine the wounding effects resulting from the removal of embryonic axes on the expression of the Cat genes in maize. In previous studies, we observed that Cat1 transcript increased in response to such minor environmental changes as removing embryos from kernels, removing plants from soil, and soaking in water [3]. We speculate that such increases in Cat transcript accumulation may be caused by a wounding-related signal. In 28 dpp embryos, the axis is still

Discussion

We have examined the expression of the three maize Cat genes in response to wounding and JA, in W64A, Vp5 wild-type, and vp5 mutant leaves, as well as in W64A embryos. Our results show that the pattern of Cat gene responses to wounding and to JA is different between embryos and leaves. In immature embryos, all three Cat genes are upregulated by wounding and JA, whereas in leaves, only the Cat1 and Cat3 genes are upregulated by wounding. In addition, application of JA does not affect Cat gene

Acknowledgements

We thank Stephanie Ruzsa and Sheri Kernodle for expert technical assistance. Research was supported in part by grants from the National Science Foundation and the Environmental Protection Agency.

References (30)

  • P.V Mylona et al.

    Modulation of antioxidant responses by arsenic in maize

    Free Radic. Biol. Med.

    (1998)
  • O.H Lowry et al.

    Protein measurement with the folin phenol reagent

    J. Biol. Chem.

    (1951)
  • S Henikoff

    Unidirectional digestion with exonuclease III creates targeted breakpoints for DNA sequencing

    Gene

    (1984)
  • J.G Scandalios et al.

    Catalases in plantsgene structure, properties, regulation, and expression

  • R Boldt et al.

    Circadian regulation of the Cat3 catalase gene in maizeentrainment of the circadian rhythm of Cat3 by different light treatments

    Plant J.

    (1995)
  • L Guan et al.

    Effects of the plant growth regulator abscisic acid and high osmoticum on the developmental expression of the maize catalase genes

    Physiol. Plant.

    (1998)
  • S.M Ruzsa et al.

    Differential response of antioxidant genes in maize leaves exposed to ozone

    Redox Report

    (1999)
  • C.K Auh et al.

    Spatial and temporal responses of the maize catalases to low temperature

    Physiol. Plant.

    (1997)
  • A.N Polidoros et al.

    Role of hydrogen peroxide and different classes of antioxidants in the regulation of catalase and glutathione S-transferase gene expression in maize (Zea mays L.)

    Physiol. Plant.

    (1999)
  • E.E Farmer et al.

    Regulation of expression of proteinase inhibitor gene by methyl jasmonate and jasmonic acid

    Physiol. Plant

    (1992)
  • S.H Doares et al.

    Oligogalacturonides and chitosan activate plant defensive genes through the octadecanoid pathway

    Proc. Natl. Acad. Sci. USA

    (1995)
  • C.A Ryan

    The search for the proteinase inhibitor-inducing factor, PIIF

    Plant Mol. Biol.

    (1992)
  • H Pena-Cortes et al.

    Signals involved in wound-induced proteinase inhibitor II gene expression in tomato and potato plants

    Proc. Natl. Acad. Sci. USA

    (1995)
  • H Peno-Cortes et al.

    Abscisic acid-deficient plants do not accumulate proteinase inhibitor II following systemin treatment

    Planta

    (1996)
  • S.J Neill et al.

    The carotenoid and abscisic acid content of viviparous kernels and seedlings of Zea mays L

    Planta

    (1986)
  • Cited by (77)

    • Hormonal seed-priming improves tomato resistance against broomrape infection

      2020, Journal of Plant Physiology
      Citation Excerpt :

      Similarly, sunflower roots infected by O. cumana showed higher levels of SOD, CAT, APX and polyphenol oxidase (PPO) activities (Yang et al., 2016). Moreover, the accumulation of H2O2 acts as a signal for the induction of other antioxidants in the cell, for example, H2O2 has been found to be responsible for the expression of the CAT gene in leaves of maize upon wounding (Guan and Scandalios, 2000). The pre-treatment of tomato seeds with IAA or SA significantly improved the plant growth and accumulation of dry matter that indicates the ability of these treatments to increase the defense mechanisms of tomato plants against the parasitic weeds.

    • Involvement of H<inf>2</inf>O<inf>2</inf> in fluazifop-P-butyl-induced cell death in bristly starbur seedlings

      2017, Pesticide Biochemistry and Physiology
      Citation Excerpt :

      KI can be oxidized by hydrogen peroxide to generate iodine, which turns blue-black with the starch [18]. DAB reacts with hydrogen peroxide and forms reddish-brown polymer [19,20]. The results using the KI-starch method are shown in Fig. 4 A.

    • Salt-induced hydrogen peroxide is involved in modulation of antioxidant enzymes in cotton

      2016, Crop Journal
      Citation Excerpt :

      High accumulation of ROS has been considered for many years to be an undesirable and harmful event in stress metabolism [10]. However, several lines of evidence have suggested that ROS also act as signaling molecules [11–17], especially hydrogen peroxide, which plays an important role in responses to abiotic stress conditions [18–21]. In plants, H2O2 is produced in mitochondria, chloroplasts, peroxisomes, and at the plasma membrane or cell wall [22].

    View all citing articles on Scopus
    View full text