A Peroxidase-Dependent Apoplastic Oxidative Burst in Cultured Arabidopsis Cells Functions in MAMP-Elicited Defense

School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom.
Plant physiology (Impact Factor: 6.84). 02/2012; 158(4):2013-27. DOI: 10.1104/pp.111.190140
Source: PubMed


Perception by plants of so-called microbe-associated molecular patterns (MAMPs) such as bacterial flagellin, referred to as pattern-triggered immunity, triggers a rapid transient accumulation of reactive oxygen species (ROS). We previously identified two cell wall peroxidases, PRX33 and PRX34, involved in apoplastic hydrogen peroxide (H2O2) production in Arabidopsis (Arabidopsis thaliana). Here, we describe the generation of Arabidopsis tissue culture lines in which the expression of PRX33 and PRX34 is knocked down by antisense expression of a heterologous French bean (Phaseolus vulgaris) peroxidase cDNA construct. Using these tissue culture lines and two inhibitors of ROS generation, azide and diphenylene iodonium, we found that perxoxidases generate about half of the H2O2 that accumulated in response to MAMP treatment and that NADPH oxidases and other sources such as mitochondria account for the remainder of the ROS. Knockdown of PRX33/PRX34 resulted in decreased expression of several MAMP-elicited genes, including MYB51, CYP79B2, and CYP81F2. Similarly, proteomic analysis showed that knockdown of PRX33/PRX34 led to the depletion of various MAMP-elicited defense-related proteins, including the two cysteine-rich peptides PDF2.2 and PDF2.3. Knockdown of PRX33/PRX34 also led to changes in the cell wall proteome, including increases in enzymes involved in cell wall remodeling, which may reflect enhanced cell wall expansion as a consequence of reduced H2O2-mediated cell wall cross-linking. Comparative metabolite profiling of a CaCl2 extract of the PRX33/PRX34 knockdown lines showed significant changes in amino acids, aldehydes, and keto acids but not fatty acids and sugars. Overall, these data suggest that PRX33/PRX34-generated ROS production is involved in the orchestration of pattern-triggered immunity in tissue culture cells.

Download full-text


Available from: Julian Philip Whitelegge
  • Source
    • "When Arabidopsis tissue culture lines generated from FBP1 antisense plants are treated with ROS inhibitors (azide and DPI) about half of the MAMP-induced H 2 O 2 can be accounted for by a peroxidase-generated reaction while the rest is likely to depend on NADPH oxidases and other sources. The expression of MAMPelicited genes including MYB51, CYP79B2, and CYP81F2 and the two cysteine-rich defence-related peptides PDF2.2 and PDF2.3 are decreased in the antisense cell lines (O'Brien et al., 2012b). The importance of peroxidase-mediated ROS formation was studied in Arabidopsis T-DNA insertion lines impaired in the expression of the PRX33 or PRX34 mRNAs. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Reactive oxygen species (ROS) have been studied for their role in plant development as well as in plant immunity. ROS were consistently observed to accumulate in the plant after the perception of pathogens and microbes and over the years, ROS were postulated to be an integral part of the defence response of the plant. In this article we will focus on recent findings about ROS involved in the interaction of plants with pathogenic fungi. We will describe the ways to detect ROS, their modes of action and their importance in relation to resistance to fungal pathogens. In addition we include some results from works focussing on the fungal interactor and from studies investigating roots during pathogen attack.
    Full-text · Article · Sep 2014 · Phytochemistry
  • Source
    • "uction in response to a pathogen elicitor , and increased susceptibility to both bacterial and fungal pathogens ( Bindschedler et al . , 2006 ; Daudi et al . , 2012 ) . Therefore , PRX33 / PRX34 are required for the pathogen - elicited oxidative burst and for the expression of a variety of proteins involved in defence and cell wall expansion ( O ' Brien et al . , 2012b ) . Similar experiments could be carried out with plants experiencing wounding , to test , for example , if plants expressing lower levels of peroxidases are more susceptible to pathogens following wounding . Another aspect of plant wounding research is the contribution of peroxidases to cell death during both the hypersensitive respons"
    [Show abstract] [Hide abstract]
    ABSTRACT: Apoplastic class III peroxidases (EC play key roles in the response of plants to pathogen infection and abiotic stresses, including wounding. Wounding is a common stress for plants that can be caused by insect or animal grazing or trampling, or result from agricultural practices. Typically, mechanical damage to a plant immediately induces a rapid release and activation of apoplastic peroxidases, and an oxidative burst of reactive oxygen species (ROS), followed by the upregulation of peroxidase genes. We discuss how plants control the expression of peroxidases genes upon wounding, and also the sparse information on peroxidase-mediated signal transduction pathways. Evidence reviewed here suggests that in many plants production of the ROS that comprise the initial oxidative burst results from a complex interplay of peroxidases with other apoplastic enzymes. Later responses following wounding include various forms of tissue healing, for example through peroxidase-dependent suberinization, or cell death. Limited data suggest that ROS-mediated death signalling during the wound response may involve the peroxidase network, together with other redox molecules. In conclusion, the ability of peroxidases to both generate and scavenge ROS plays a key role in the involvement of these enigmatic enzymes in plant stress tolerance.
    Full-text · Article · Jul 2014 · Phytochemistry
  • Source
    • "Events of plant defense against pathogenic microorganisms, represented by plant cellular perception of microbial molecules contributing to so-called microbe-associated molecular patterns (MAMPs) such as bacterial flagellin, referred to as patterntriggered immunity, reportedly trigger a rapid and transient accumulation of ROS (O'Brien et al., 2012a). In Arabidopsis, molecular evidence for involvement of two identified cell wall POXs, namely, PRX33 and PRX34, in MAMPs-responsive apoplastic ROS generation has been reported (Bindschedler et al., 2006; O'Brien et al., 2012a,b). "
    [Show abstract] [Hide abstract]
    ABSTRACT: When plants are threaten by microbial attacks or treated with elicitors, alkalization of extracellular space is often induced and thus pH-dependent extracellular peroxidase-mediated oxidative burst reportedly takes place, especially at the site of microbial challenge. However, direct stimulus involved in activation of peroxidase-catalyzed oxidative burst has not been identified to date. Here, we would like to propose a likely role for free ferrous ion in reduction of ferric native peroxidase into ferrous enzyme intermediate which readily produces superoxide anion via mechanism involving Compound III, especially under alkaline condition, thus, possibly contributing to the plant defense mechanism. Through spectroscopic and chemiluminescence (CL) analyses of reactions catalyzed by horseradish peroxidase (HRP), the present study proposed that plant peroxidase-catalyzed production of superoxide anion can be stimulated in the absence of conventional peroxidase substrates but in the presence of free ferrous ion.
    Full-text · Article · Jul 2014 · Frontiers in Plant Science
Show more