Ectopic Expression of an <i>Arabidopsis</i> Calmodulin-Like Domain Protein Kinase-Enhanced NADPH Oxidase Activity and Oxidative Burst in Tomato Protoplasts

Xing, Tim; Wang, Xiaojing; Malik, Kamal; Miki, Brian

doi:10.1094/mpmi.2001.14.10.1261

Cited by 96 publications

(47 citation statements)

References 27 publications

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“…We speculate that CDPK1 may be involved in the transient regulation of localized ROS accumulation in root cells at a particular stage of development or in response to specific environmental signals. Consistent with this possibility, CDPKs have been shown to be involved in the defense response and are also involved in the modification of NADPH oxidase activity (Romeis et al, 2000;Xing et al, 2001;Cheng et al, 2002;Ludwig et al, 2004). Furthermore, ROS and Ca 2þ signals can operate in tandem and have been implicated in root hair elongation, the defense response, and cell wall biosynthesis (Foreman et al, 2003;.…”

Section: Discussionmentioning

confidence: 84%

RNA Interference Identifies a Calcium-Dependent Protein Kinase Involved inMedicago truncatulaRoot Development

et al. 2005

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Changes in cellular or subcellular Ca2+ concentrations play essential roles in plant development and in the responses of plants to their environment. However, the mechanisms through which Ca2+ acts, the downstream signaling components, as well as the relationships among the various Ca2+-dependent processes remain largely unknown. Using an RNA interference–based screen for gene function in Medicago truncatula, we identified a gene that is involved in root development. Silencing Ca2+-dependent protein kinase1 (CDPK1), which is predicted to encode a Ca2+-dependent protein kinase, resulted in significantly reduced root hair and root cell lengths. Inactivation of CDPK1 is also associated with significant diminution of both rhizobial and mycorrhizal symbiotic colonization. Additionally, microarray analysis revealed that silencing CDPK1 alters cell wall and defense-related gene expression. We propose that M. truncatula CDPK1 is a key component of one or more signaling pathways that directly or indirectly modulates cell expansion or cell wall synthesis, possibly altering defense gene expression and symbiotic interactions.

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Section: Discussionmentioning

confidence: 84%

RNA Interference Identifies a Calcium-Dependent Protein Kinase Involved inMedicago truncatulaRoot Development

et al. 2005

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“…It has been suggested that CDPKs may mediate this indirect calcium regulation (Mehdy, 1994;Xing et al, 1997;Romeis et al, 2000). Recent data revealing that ectopic expression of AtCPK1 can enhance NADPH oxidase activity in a cell-free system and in tomato protoplasts (Xing et al, 2001) support these studies.…”

Section: Pathogen Defensementioning

confidence: 88%

Calcium Signaling through Protein Kinases. The Arabidopsis Calcium-Dependent Protein Kinase Gene Family

et al. 2002

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In plants, numerous Ca2+-stimulated protein kinase activities occur through calcium-dependent protein kinases (CDPKs). These novel calcium sensors are likely to be crucial mediators of responses to diverse endogenous and environmental cues. However, the precise biological function(s) of most CDPKs remains elusive. The Arabidopsis genome is predicted to encode 34 different CDPKs. In this Update, we analyze the Arabidopsis CDPK gene family and review the expression, regulation, and possible functions of plant CDPKs. By combining emerging cellular and genomic technologies with genetic and biochemical approaches, the characterization of Arabidopsis CDPKs provides a valuable opportunity to understand the plant calcium-signaling network.

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“…Several studies have suggested that this phosphorylation is mediated by calcium-dependent protein kinases (CDPKs). Ectopic expression of an Arabidopsis CDPK enhanced NADPH oxidase activity and stimulated an oxidative burst in tomato protoplasts (44). Recently, Benschop et al (45) showed that seven different residues in AtrbohD were phosphorylated in response to elicitors, using mass spectrometry and quantitative phospho-proteomics.…”

Section: Discussionmentioning

confidence: 99%

Synergistic Activation of the Arabidopsis NADPH Oxidase AtrbohD by Ca2+ and Phosphorylation

Ogasawara

Kaya

Hiraoka

et al. 2008

Journal of Biological Chemistry

427

312

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Plant respiratory burst oxidase homolog (rboh) proteins, which are homologous to the mammalian 91-kDa glycoprotein subunit of the phagocyte oxidase (gp91 phox ) or NADPH oxidase 2 (NOX2), have been implicated in the production of reactive oxygen species (ROS) both in stress responses and during development. Unlike mammalian gp91 phox /NOX2 protein, plant rboh proteins have hydrophilic N-terminal regions containing two EF-hand motifs, suggesting that their activation is dependent on Ca 2؉ . However, the significance of Ca 2؉ binding to the EF-hand motifs on ROS production has been unclear. By employing a heterologous expression system, we showed that ROS production by Arabidopsis thaliana rbohD (AtrbohD) was induced by ionomycin, which is a Ca 2؉ ionophore that induces Ca 2؉ influx into the cell. This activation required a conformational change in the EF-hand region, as a result of Ca 2؉ binding to the EF-hand motifs. We also showed that AtrbohD was directly phosphorylated in vivo, and that this was enhanced by the protein phosphatase inhibitor calyculin A (CA). Moreover, CA itself induced ROS production and dramatically enhanced the ionomycin-induced ROS production of AtrbohD. Our results suggest that Ca 2؉ binding and phosphorylation synergistically activate the ROS-producing enzyme activity of AtrbohD.Photosynthetic plants have developed various mechanisms to cope with oxidative stress, such as the production of antioxidants and enzymes that scavenge reactive oxygen species (ROS).3 Plants are also equipped with mechanisms for producing ROS in response to internal and external stimuli. ROS production is induced during many physiological processes, including stress responses, cell growth, hormonal responses, stomatal closure, and disease resistance (see Refs. 1-4 and references therein).ROS production is induced in plants in response to recognition of pathogenic signals, such as pathogen/microbe-associated molecular patterns (PAMPs/MAMPs) or elicitors. Elicitor-induced ROS production is preceded by a rapid increase in the cytosolic free Ca 2ϩ concentration ([Ca 2ϩ ] cyt ) (5-7) and is inhibited both by Ca 2ϩ chelators such as EGTA and BAPTA, and by Ca 2ϩ channel blockers such as La 3ϩ (6,8). The overexpression of rice two-pore channel 1 (OsTPC1), which is a putative voltage-gated Ca 2ϩ channel, enhanced elicitor-induced ROS production (9). Elicitor-induced ROS production is also inhibited by diphenylene iodonium (DPI), which is known to inhibit NADPH oxidase activity (6, 10). NADPH oxidase activity in the microsomal membrane fraction from tomato and tobacco was activated by adding Ca 2ϩ in vitro (11), suggesting that elicitor-induced ROS production by plant NADPH oxidase might be dependent on Ca 2ϩ . In mammalian phagocytes, ROS production is mediated by the NADPH-dependent phagocytic oxidase (phox) complex, which consists of the catalytic subunit gp91 phox /NADPH oxidase (NOX) 2, together with the regulatory subunits p22 phox , p40 phox , p47 phox , p67 phox , and the small GTP-binding protein Rac (12). In...

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Ectopic Expression of an Arabidopsis Calmodulin-Like Domain Protein Kinase-Enhanced NADPH Oxidase Activity and Oxidative Burst in Tomato Protoplasts

Cited by 96 publications

References 27 publications

RNA Interference Identifies a Calcium-Dependent Protein Kinase Involved inMedicago truncatulaRoot Development

RNA Interference Identifies a Calcium-Dependent Protein Kinase Involved inMedicago truncatulaRoot Development

Calcium Signaling through Protein Kinases. The Arabidopsis Calcium-Dependent Protein Kinase Gene Family

Synergistic Activation of the Arabidopsis NADPH Oxidase AtrbohD by Ca2+ and Phosphorylation

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