Phytoglobins can interfere with nitric oxide functions during plant growth and pathogenic responses: a transgenic approach

Seregélyes, Csaba; Barna, B.; Hennig, Jacek; Konopka, D; Pasternak, Taras; Lukàcs, Noèmi; Fehér, Attila; Horváth, Gábor; Dudits, Dénes

doi:10.1016/s0168-9452(03)00213-9

Cited by 59 publications

(49 citation statements)

References 49 publications

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“…In animal tissues, dioxygen-dependent metabolism of NO is likely connected with heme-and flavoprotein (Gardner et al 2001); however, a particular Hb and flavin has not been identified. In plants, class 1 Hbs have been implicated in NO metabolism (Hill 1998;Dordas et al 2003aDordas et al , 2003bSerege´lyes et al 2003). In the present investigation, we report for the first time the presence of NAD(P)H-dependent NO dioxygenase-like activity in plants, and present evidence that it is connected with the function of a plant class 1 Hb.…”

Section: Introductionsupporting

confidence: 66%

NADH-dependent metabolism of nitric oxide in alfalfa root cultures expressing barley hemoglobin

Igamberdiev

Seregélyes

Manac′h

et al. 2004

Planta

139

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Transgenic alfalfa ( Medicago sativa L.) root cultures expressing sense and antisense barley ( Hordeum vulgare L.) hemoglobin were examined for their ability to metabolize NO. Extracts from lines overexpressing hemoglobin had approximately twice the NO conversion rate of either control or antisense lines under normoxic conditions. Only the control line showed a significant increase in the rate of NO degradation when placed under anaerobic conditions. The decline in NO was dependent on the presence of reduced pyridine nucleotide, with the NADH-dependent rate being about 2.5 times faster than the NADPH-dependent rate. Most of the activity was found in the cytosolic fraction of the extracts, while only small amounts were found in the cell wall, mitochondria, and 105,000- g membrane fraction. The NADH-dependent NO conversion exhibited a broad pH optimum in the range 7-8 and a strong affinity to NADH and NADPH ( K(m) 3 microM for both). It was sensitive to diphenylene iodonium, an inhibitor of flavoproteins. The activity was strongly reduced by applying antibodies raised against recombinant barley hemoglobin. Extracts of Escherichia coli overexpressing barley hemoglobin showed a 4-fold higher rate of NO metabolism as compared to non-transformed cells. The NADH/NAD and NADPH/NADP ratios were higher in lines underexpressing hemoglobin, indicating that the presence of hemoglobin has an effect on these ratios. They were increased under hypoxia and antimycin A treatment. Alfalfa root extracts exhibited methemoglobin reductase activity, using either cytochrome c or recombinant barley hemoglobin as substrates. There was a correspondence between NO degradation and nitrate formation. The activity was eluted from a Superose 12 column as a single peak with molecular weight of 35+/-4 kDa, which corresponds to the size of the hemoglobin dimer. The results are consistent with an NO dioxygenase-like activity, with hemoglobin acting in concert with a flavoprotein, to metabolize NO to nitrate utilizing NADH as the electron donor.

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Section: Introductionsupporting

confidence: 66%

NADH-dependent metabolism of nitric oxide in alfalfa root cultures expressing barley hemoglobin

Igamberdiev

Seregélyes

Manac′h

et al. 2004

Planta

139

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“…A regulatory involvement of hemoglobins with some of the NO-dependent processes has been suggested (Crawford and Guo 2005) but has so far only been shown for the hypoxic response Hill 2004, Perazzolli et al 2004) and for pathogen responses (Seregelyes et al 2003, although contradictory results exist regarding pathogen response (Perazzolli et al 2004). In this study, two independent lines silenced in AHb1 show the same mutant phenotype, indicating that hemoglobin apart from a specialized function in hypoxic stress response plays an essential role in scavenging of endotoxic NO during normal development.…”

Section: Discussionmentioning

confidence: 99%

Hemoglobin is essential for normal growth of Arabidopsis organs

Hebelstrup

Hunt

Dennis

et al. 2006

Physiologia Plantarum

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In Arabidopsis thaliana, the class I hemoglobin AHb1 is transiently expressed in the hydathodes of leaves and in floral buds from young inflorescences. Nitric oxide (NO) accumulates to high levels in these organs when AHb1 is silenced, indicating an important role in metabolizing NO. AHb1-silenced lines are viable but show a mutant phenotype affecting the regions where AHb1 is expressed. Arabidopsis lines with an insertional knockout or overexpression of AHb2, a class II 3-on-3 hemoglobin, were generated. Seedlings overexpressing AHb2 show enhanced survival of hypoxic stress. The AHb2 knockout lines develop normally. However, when AHb2 knockout is combined with AHb1 silencing, seedlings die at an early vegetative stage suggesting that the two 3-on-3 hemoglobins, AHb1 and AHb2, together play an essential role for normal development of Arabidopsis seedlings. In conclusion, these results suggests that 3-on-3 hemoglobins apart from a role in hypoxic stress play a general role under non-stressed conditions where they are essential for normal development by controlling the level of NO which tends to accumulate in floral buds and leaf hydathodes of plants.

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“…By contrast, other reports indicate that NO acts as an antioxidant. In transgenic tobacco (Nicotiana tabacum) plants expressing alfalfa (Medicago sativa) hemoglobin (a NO-scavenging enzyme), ROS levels are higher than in control plants during bacterial infection, indicating that NO normally suppresses ROS accumulation (Seregelyes et al, 2003). NO donors counteract photooxidative damage during treatment with methyl viologen herbicides by reducing H 2 O 2 , O 2 ÿ , and ÁOH radical levels and slowing ion leakage, protein and lipid oxidation, loss of chlorophyll, and protein degradation Lamattina, 1999, 2002).…”

Section: Nos1 Attenuates Ros Levels and Oxidative Stressmentioning

confidence: 99%

Arabidopsis Nitric Oxide Synthase1 Is Targeted to Mitochondria and Protects against Oxidative Damage and Dark-Induced Senescence

2005

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The Arabidopsis thaliana protein nitric oxide synthase1 (NOS1) is needed for nitric oxide (NO) synthesis and signaling during defense responses, hormonal signaling, and flowering. The cellular localization of NOS1 was examined because it is predicted to be a mitochondrial protein. NOS1-green fluorescent protein fusions were localized by confocal microscopy to mitochondria in roots. Isolated mitochondria from leaves of wild-type plants supported Arg-stimulated NO synthesis that could be inhibited by NOS inhibitors and quenched by a NO scavenger; this NOS activity is absent in mitochondria isolated from nos1 mutant plants. Because mitochondria are a source of reactive oxygen species (ROS), which participate in senescence and programmed cell death, these parameters were examined in the nos1 mutant. Dark-induced senescence of detached leaves and intact plants progressed more rapidly in the mutant compared with the wild type. Hydrogen peroxide, superoxide anion, oxidized lipid, and oxidized protein levels were all higher in the mutant. These results demonstrate that NOS1 is a mitochondrial NOS that reduces ROS levels, mitigates oxidative damage, and acts as an antisenescence agent.

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Phytoglobins can interfere with nitric oxide functions during plant growth and pathogenic responses: a transgenic approach

Cited by 59 publications

References 49 publications

NADH-dependent metabolism of nitric oxide in alfalfa root cultures expressing barley hemoglobin

NADH-dependent metabolism of nitric oxide in alfalfa root cultures expressing barley hemoglobin

Hemoglobin is essential for normal growth of Arabidopsis organs

Arabidopsis Nitric Oxide Synthase1 Is Targeted to Mitochondria and Protects against Oxidative Damage and Dark-Induced Senescence

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