Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.6 (NADPH oxidase)
 10,295 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reactive oxygen intermediates (ROI) are closely related to defence reactions of plants against pathogens. A prominent role in the production of ROI has been attributed to the plant respiratory burst oxidase homologues (RBOH) of the human phagocyte GP91(phox). A barley RBOH, which encodes a putative superoxide (O2*-)) producing NADPH oxidase, is described here. Histochemical analysis of the barley-Blumeria graminis f. sp. hordei (Bgh) interaction showed that O(2*-) is produced locally at the site of penetration. In contrast, hydrogen peroxide (H2O2) is produced in non-penetrated cell wall appositions. A barley RBOHA cDNA was isolated and a minor induction of expression of RBOHA was observed during the interactions of barley with Bgh. Transient RNA interference-mediated gene silencing of HvRBOHA during the penetration process of Bgh led to an increase of basal penetration resistance. The results support a potential role of HvRBOHA in cellular accessibility to Blumeria graminis.
J Exp Bot 2006
PMID:Respiratory burst oxidase homologue A of barley contributes to penetration by the powdery mildew fungus Blumeria graminis f. sp. hordei. 1704 82

Plant growth is severely affected by toxic concentrations of heavy metals. On characterizing the heavy metal-induced signalling pathways, the effects of cadmium (CdCl2) and copper (CuCl2) on MBP (myelin basic protein) kinase activities in Oryza sativa L. cv. TNG67 were analysed and it was found that Cd2+-induced 42 kDa MBP kinase has the characteristics of a mitogen-activated protein (MAP) kinase. This study confirmed that the 42 kDa kinase-active band contains, at least, the activities of OsMPK3 and OsMPK6. Then, the heavy metal signal transduction pathways leading to MAP kinase activation in rice roots were examined. Pretreatment with sodium benzoate, a hydroxyl radical scavenger, attenuated Cd2+- or Cu2+-induced MAP kinase activation. The Cd2+-, but not Cu2+-, induced MAP kinase activities were suppressed by diphenylene iodonium (DPI), an NADPH oxidase inhibitor, and Cd2+ induced NADPH oxidase-like activities, suggesting that NADPH oxidases may be involved in Cd2+-induced MAP kinase activation. Using a Ca2+ indicator, it was demonstrated that Cd2+ and Cu2+ induce Ca2+ accumulation in rice roots. The Cd2+- and Cu2+-induced MAP kinase activation required the involvement of Ca2+-dependent protein kinase (CDPK) and phosphatidylinositol 3-kinase (PI3 kinase) as shown by the inhibitory effect of a CDPK antagonist, W7, and a PI3 kinase inhibitor, wortmannin, respectively. Furthermore, bongkrekic acid (BK), a mitochondrial permeability transition pore opening blocker, suppressed Cd2+-, but not Cu2+-, induced MAP kinase activation, indicating that Cd2+-induced MAP kinase activities are dependent on the functional state of mitochondria. Collectively, these findings imply that Cd2+ and Cu2+ may induce MAP kinase activation through distinct signalling pathways. Moreover, it was found that the 42 kDa MAP kinase activities are higher in Cd-tolerant cultivars than in Cd-sensitive cultivars. Therefore, the Cd-induced 42 kDa MAP kinase activation may confer Cd tolerance in rice plants.
J Exp Bot 2007
PMID:Distinct signalling pathways for induction of MAP kinase activities by cadmium and copper in rice roots. 1725 46

Reactive oxygen species (ROS) production by an NADPH oxidase (NOX) encoded by AtrbohC/RHD2 is required for root hair growth in Arabidopsis thaliana. ROP (RHO of plants) GTPases are also required for normal root hair growth and have been proposed to regulate ROS production in plants. Therefore, the role of ROP GTPase in NOX-dependent ROS formation by root hairs was investigated. Plants overexpressing wild-type ROP2 (ROP2 OX), constitutively active (CA-rop2), or dominant negative (DN-rop2) rop2 mutant proteins were used. Superoxide formation by root hairs was detected by superoxide dismutase-sensitive nitroblue tetrazolium reduction, and ROS production in the root hair differentiation zone was detected by dihydrofluorescein diacetate oxidation. Both probes showed that ROS production was increased in ROP2 OX and CA-rop2 plants, and decreased in DN-rop2 plants, relative to wild-type plants. When CA-rop2 was expressed in the NOX loss-of-function rhd2-1 mutant, ROS formation and root hair growth were impaired, suggesting that RHD2 is required for this ROP2-dependent ROS formation.
J Exp Bot 2007
PMID:NADPH oxidase-dependent reactive oxygen species formation required for root hair growth depends on ROP GTPase. 1730 Oct 29

To provide an insight into the mechanism of interspecific interactions mediated by allelochemicals, cucumber and figleaf gourd seedlings were compared on their response to cinnamic acid, an autotoxin from root exudates of cucumber. Reactive oxygen species metabolism and plasma membrane H(+)-ATPase activity were examined in roots upon exposure to cinnamic acid. This exposure resulted in significant increases in activities of NADPH oxidase, superoxide dismutase, guaiacol peroxidase, and catalase, as well as in O(2)(.-) production and H(2)O(2) content, in cucumber roots but not in figleaf gourd roots. Notably, the cucumber roots produced significant amount of reactive oxygen species (ROS) immediately after cinnamic acid treatment, consequently increasing membrane peroxidation, decreasing membrane H(+)-ATPase activity, and losing root viability. By contrast, no such changes were observed in figleaf gourd roots. All these results indicated that there was an interspecies difference in the recognition of allelochemicals, which induced oxidative stress accompanied by root cell death in cucumber, an autotoxic plant, but not in figleaf gourd, a cucumber relative.
J Exp Bot 2007
PMID:Physiological basis of different allelopathic reactions of cucumber and figleaf gourd plants to cinnamic acid. 1796 43

In Arabidopsis thaliana cells, fusicoccin (FC) treatment induced an early and marked increase in the extracellular H(2)O(2) level. It also increased the huge hypo-osmotic stress-induced oxidative wave and, in addition, prevented the H(2)O(2) peak drop. These effects were apparently not linked to changes in either cytoplasmic pH or cytoplasmic free calcium concentration, since they occurred independently of the activity state of the plasma membrane (PM) H(+)-ATPase and neither influx nor efflux of (45)Ca(2+) was modified by FC. In the presence of diphenylene iodonium (DPI), inhibiting the PM NADPH oxidase presumably responsible for reactive oxygen species (ROS) production, no apoplastic H(2)O(2) development was detected either with or without FC. However, no increase in DPI-sensitive ferricyanide reduction, but rather a gradual decrease, occurred with FC. These results suggested that the H(2)O(2) increase observed with FC was not due to a overproduction of ROS but, more probably, to a reduced capability of FC-treated cells to degrade the H(2)O(2) formed. This view, at first supported by the finding that FC-treated cells failed to break down exogenously supplied H(2)O(2), was clearly confirmed by a series of measurements on exogenous catalase activity, tested in cell-free media of FC-treated samples. This assay, in fact, allowed ascertainment and partial characterization of an as yet unidentified factor increasingly accumulating in the incubation medium of FC-treated cells, behaving as a non-competitive catalase inhibitor and able to reduce markedly the cell's capability for H(2)O(2) scavenging.
J Exp Bot 2007
PMID:Inhibition of catalase activity as an early response of Arabidopsis thaliana cultured cells to the phytotoxin fusicoccin. 1803 36

One of the most important functions of blue light (BL) is to induce chloroplast movements in order to reduce the damage to the photosynthetic machinery under excess light. Hydrogen peroxide (H(2)O(2)), which is commonly generated under various environmental stimuli, can act as a signalling molecule that regulates a number of developmental processes and stress responses. To investigate whether H(2)O(2) is involved in high-fluence BL-induced chloroplast avoidance movements, a laser scanning confocal microscope and a luminescence spectrometer were used to observe H(2)O(2) generation in situ with the assistance of the fluorescence probe dichlorofluorescein diacetate (H(2)DCF-DA). After treatment with high-fluence BL, an enhanced accumulation of H(2)O(2), indicated by the fluorescence intensity of DCF, can be observed in leaf cells of Arabidopsis thaliana. Exogenously applied H(2)O(2) promotes the high-fluence BL-induced chloroplast movements in a concentration-dependent manner within the range of 0-10(-4) M, not only increasing the degree of movements but also accelerating the start of migrations. Moreover, the high-fluence BL-induced H(2)O(2) generation and the subsequent chloroplast movements can be largely abolished by the administration of the H(2)O(2)-specific scavenger catalase and other antioxidants. In addition, in-depth subcellular experiments indicated that high-fluence BL-induced H(2)O(2) generation can be partly abolished by the addition of diphenyleneiodonium (DPI), which is an NADPH oxidase inhibitor, and the blocker of electron transport chain dichlorophenyl dimethylurea (DCMU), respectively. The results presented here suggest that high-fluence BL can induce H(2)O(2) generation at both the plasma membrane and the chloroplast, and that the production of H(2)O(2) is involved in high-fluence BL-induced chloroplast avoidance movements.
J Exp Bot 2008
PMID:Hydrogen peroxide is involved in high blue light-induced chloroplast avoidance movements in Arabidopsis. 1855 May 99

Active oxygen species (AOS) are central components of the defence reactions of plants against pathogens. Plant respiratory burst oxidase homologues (RBOH) of gp91(phox), a plasma membrane protein of the neutrophil nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, play a prominent role in AOS production. The role of two RBOH from Nicotiana benthamiana, NbrbohA and NbrbohB that encode plant NADPH oxidase in the process of elicitor-induced stomatal closure and hypersensitive cell death is described here. NbrbohA was constitutively expressed at a low level, whereas NbrbohB was induced when protein elicitors exist (such as boehmerin, harpin, or INF1). The virus-induced gene-silencing (VIGS) method was used to produce single-silenced (NbrbohA or NbrbohB) and double-silenced (NbrbohA and NbrbohB) N. benthamiana plants. The hypersensitive response (HR) of cell death and pathogenesis-related (PR) gene expression of these gene-silenced N. benthamiana plants, induced by various elicitors, are examined. The HR cell death and transcript accumulation of genes related to the defence response (PR1) were slightly affected, suggesting that RBOH are not essential for elicitor-induced HR and activation of these genes. Interestingly, gene-silenced plants impaired elicitor-induced stomatal closure and elicitor-promoted nitric oxide (NO) production, but not elicitor-induced cytosolic calcium ion accumulation and elicitor-triggered AOS production in guard cells. These results indicate that RBOH from N. benthamiana function in elicitor-induced stomatal closure, but not in elicitor-induced HR.
J Exp Bot 2009
PMID:The role of respiratory burst oxidase homologues in elicitor-induced stomatal closure and hypersensitive response in Nicotiana benthamiana. 1945 96

In maize (Zea mays), abscisic acid (ABA)-induced H(2)O(2) production activates a 46 kDa mitogen-activated protein kinase (p46MAPK), and the activation of p46MAPK also regulates the production of H(2)O(2). However, the mechanism for the regulation of H(2)O(2) production by MAPK in ABA signalling remains to be elucidated. In this study, four reactive oxygen species (ROS)-producing NADPH oxidase (rboh) genes (ZmrbohA-D) were isolated and characterized in maize leaves. ABA treatment induced a biphasic response (phase I and phase II) in the expression of ZmrbohA-D and the activity of NADPH oxidase. Phase II induced by ABA was blocked by pretreatments with two MAPK kinase (MPKKK) inhibitors and two H(2)O(2) scavengers, but phase I was not affected by these inhibitors or scavengers. Treatment with H(2)O(2) alone also only induced phase II, and the induction was arrested by the MAPKK inhibitors. Furthermore, the ABA-activated p46MAPK was partially purified. Using primers corresponding to the sequences of internal tryptic peptides, the p46MAPK gene was cloned. Analysis of the tryptic peptides and the p46MAPK sequence indicate it is the known ZmMPK5. Treatments with ABA and H(2)O(2) led to a significant increase in the activity of ZmMPK5, although ABA treatment only induced a slight increase in the expression of ZmMPK5. The data indicate that H(2)O(2)-activated ZmMPK5 is involved in the activation of phase II in ABA signalling, but not in phase I. The results suggest that there is a positive feedback loop involving NADPH oxidase, H(2)O(2), and ZmMPK5 in ABA signalling.
J Exp Bot 2009
PMID:Positive feedback regulation of maize NADPH oxidase by mitogen-activated protein kinase cascade in abscisic acid signalling. 1959 1

A full-length drought-responsive gene Ccrboh, encoding the respiratory burst oxidase homologue (rboh), was cloned in Citrullus colocynthis, a very drought-tolerant cucurbit species. The robh protein, also named NADPH oxidase, is conserved in plants and animals, and functions in the production of reactive oxygen species (ROS). The Ccrboh gene accumulated in a tissue-specific pattern when C. colocynthis was treated with PEG, abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), or NaCl, while the homologous rboh gene did not show any change in C. lanatus var. lanatus, cultivated watermelon, during drought. Grafting experiments were conducted using C. colocynthis or C. lanatus as the rootstock or scion. Results showed that the rootstock significantly affects gene expression in the scion, and some signals might be transported from the root to the shoot. Ccrboh in C. colocynthis was found to function early during plant development, reaching high mRNA transcript levels 3 d after germination. The subcellular location of Ccrboh was investigated by transient expression of the 35S::Ccrboh::GFP fusion construct in protoplasts. The result confirmed that Ccrboh is a transmembrane protein. Our data suggest that Ccrboh might be functionally important during the acclimation of plants to stress and also in plant development. It holds great promise for improving drought tolerance of other cucurbit species.
J Exp Bot 2010 Jun
PMID:Cloning and expression analysis of the Ccrboh gene encoding respiratory burst oxidase in Citrullus colocynthis and grafting onto Citrullus lanatus (watermelon). 2018 64

In higher plants, copper ions, hydrogen peroxide, and cycloheximide have been recognized as very effective inducers of the transcriptional activity of genes encoding the enzymes of the ethylene biosynthesis pathway. In this report, the transcriptional patterns of genes encoding the 1-aminocyclopropane-1-carboxylate synthases (ACSs), 1-aminocyclopropane-1-carboxylate oxidases (ACOs), ETR1, ETR2, and ERS1 ethylene receptors, phospholipase D (PLD)-alpha1, -alpha2, -gamma1, and -delta, and respiratory burst oxidase homologue (Rboh)-NADPH oxidase-D and -F in response to these inducers in Brassica oleracea etiolated seedlings are shown. ACS1, ACO1, ETR2, PLD-gamma1, and RbohD represent genes whose expression was considerably affected by all of the inducers used. The investigations were performed on the seedlings with (i) ethylene insensitivity and (ii) a reduced level of the PLD-derived phosphatidic acid (PA). The general conclusion is that the expression of ACS1, -3, -4, -5, -7, and -11, ACO1, ETR1, ERS1, and ETR2, PLD-gamma 1, and RbohD and F genes is undoubtedly under the reciprocal cross-talk of the ethylene and PA(PLD) signalling routes; both signals affect it in concerted or opposite ways depending on the gene or the type of stimuli. The results of these studies on broccoli seedlings are in agreement with the hypothesis that PA may directly affect the ethylene signal transduction pathway via an inhibitory effect on CTR1 (constitutive triple response 1) activity.
J Exp Bot 2010 Jul
PMID:Exogenously induced expression of ethylene biosynthesis, ethylene perception, phospholipase D, and Rboh-oxidase genes in broccoli seedlings. 2058 Nov 25


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