Ascorbate synthesis and ascorbate peroxidase activity during the early stage of wheat germination

Gara, Laura De; Pinto, Maria Concetta de; Arrigoni, O.

doi:10.1111/j.1399-3054.1997.tb00015.x

Cited by 83 publications

(95 citation statements)

References 27 publications

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“…The high activity of the ASC recycling enzyme MDHAR and the increasing levels of MDHA and DHA in BSO-treated embryos may be a strategy to eYciently regenerate ASC at the onset of germination, prior to the complete reactivation of the de novo ASC biosynthetic pathway. These metabolic alterations, documented during normal embryonic growth in vivo and in vitro (De Gara et al 1997;Stasolla and Yeung 2001), are not observed in control embryos. The potential to quickly regenerate ASC from MDHA in the presence of an oxidized glutathione environment may explain the improved conversion frequency of BSO-treated embryos (Belmonte et al 2006).…”

Section: Antioxidant Responsementioning

confidence: 70%

Buthionine sulfoximine (BSO)-mediated improvement in cultured embryo quality in vitro entails changes in ascorbate metabolism, meristem development and embryo maturation

Stasolla

Belmonte

Tahir

et al. 2008

Planta

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Applications of buthionine sulfoximine (BSO), an inhibitor of GSH (reduced glutathione), which switches the cellular glutathione pool towards the oxidized form GSSG, positively inXuences embryo quality by improving the structure of the shoot apical meristem and promoting embryo maturation, both of which improve the post-embryonic performance of the embryos. To investigate the mechanisms underlying BSO-mediated improvement in embryo quality the transcript proWles of developing Brassica napus microspore-derived embryos cultured in the absence (control) or presence of BSO were analyzed using a 15,000-element B. napus oligo microarray. BSO applications induced major changes in transcript accumulation patterns, especially during the late phases of embryogenesis. BSO aVected the transcription and activities of key enzymes involved in ascorbate metabolism, which resulted in major Xuctuations in cellular ascorbate levels. These changes were related to morphological characteristics of the embryos and their postembryonic performance. BSO applications also activated many genes controlling meristem formation and function, including ZWILLE, SHOOTMERISTEMLESS, and ARG-ONAUTE 1. Increased expression of these genes may contribute to the improved structural quality of the shoot poles observed in the presence of BSO. Compared to their control counterparts, middle-and late-stage BSO-treated embryos also showed increased accumulation of transcripts associated with the maturation phase of zygotic embryo development, including genes encoding ABA-responsive proteins and storage-and late-embryogenic abundant (LEA) proteins. Overall these transcriptional changes support the observation that the BSO-induced oxidized glutathione redox state allows cultured embryos to reach both morphological and physiological maturity, which in turn guarantees successful regeneration and enhanced post-embryonic growth.

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Section: Antioxidant Responsementioning

confidence: 70%

Buthionine sulfoximine (BSO)-mediated improvement in cultured embryo quality in vitro entails changes in ascorbate metabolism, meristem development and embryo maturation

Stasolla

Belmonte

Tahir

et al. 2008

Planta

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“…Soluble proteins were extracted from 2 g of a 3-d-old BY-2 culture with 20 mL of the buffer described in De Gara et al (1997). Native gel electrophoresis and subsequent staining for GSSG reductase activity was performed according to Foyer et al (1991).…”

Section: Native Page Gssg Reductase Assaymentioning

confidence: 99%

Dehydroascorbate Influences the Plant Cell Cycle through a Glutathione-Independent Reduction Mechanism

et al. 2004

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Glutathione is generally accepted as the principal electron donor for dehydroascorbate (DHA) reduction. Moreover, both glutathione and DHA affect cell cycle progression in plant cells. But other mechanisms for DHA reduction have been proposed. To investigate the connection between DHA and glutathione, we have evaluated cellular ascorbate and glutathione concentrations and their redox status after addition of dehydroascorbate to medium of tobacco (Nicotiana tabacum) L. cv Bright Yellow-2 (BY-2) cells. Addition of 1 mM DHA did not change the endogenous glutathione concentration. Total glutathione depletion of BY-2 cells was achieved after 24-h incubation with 1 mM of the glutathione biosynthesis inhibitor L-buthionine sulfoximine. Even in these cells devoid of glutathione, complete uptake and internal reduction of 1 mM DHA was observed within 6 h, although the initial reduction rate was slower. Addition of DHA to a synchronized BY-2 culture, or depleting its glutathione content, had a synergistic effect on cell cycle progression. Moreover, increased intracellular glutathione concentrations did not prevent exogenous DHA from inducing a cell cycle shift. It is therefore concluded that, together with a glutathione-driven DHA reduction, a glutathione-independent pathway for DHA reduction exists in vivo, and that both compounds act independently in growth control.

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“…It has been widely reported that APX plays a key role in removing the toxic H 2 O 2 in plant cells, 35,36,37 the correct temporal expression of APX has to be an important factor for seed germination. 38 APX activity in the two cultivar seeds disappeared at the end of their development and did not show any significant differences during seed maturation (Fig. 5A).…”

Section: Discussionmentioning

confidence: 99%

Hydrogen peroxide scavenging regulates germination ability during wheat (Triticum aestivumL.) seed maturation

Ishibashi¹,

Yamamoto²,

Tawaratsumida

et al. 2008

Plant Signaling & Behavior

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Hydrogen peroxide (H 2 O 2 ) promotes seed germination of cereal plants and ascorbic acid which acts as antioxidant suppresses the germination of wheat seeds, but the role of H 2 O 2 scavenging on germination during seed maturation has not been demonstrated. We investigated relationship of germination, ascorbate, H 2 O 2 scavenging enzymes and sensitivity to ascorbic acid (AsA) maturing seeds of two typical wheat (Triticum aestivum L.) cultivars, cvs. Shirogane-Komugi and Norin61. Shirogane-Komugi had marked high germination ability than Norin61 during seed maturation. Although the H 2 O 2 content had no difference in the two cultivars, sensitivity to AsA of Norin61 seeds was higher than that of Shirogane-Komugi seeds during seed maturation. The sensitivity to AsA closely correlated with germination characteristic in the two cultivars. Especially, at 28 days after pollination (DAP), sensitivity to AsA in Norin61 seeds was remarkably high. At that stage, no significant differences were observed in endogenous AsA level, ascorbate peroxidase (APX, EC 1.11.1.11) and dehydroascorbate reductase (DHAR, EC 1.8.5.1) activities in the two cultivars. However, catalase (CAT, EC 1.11.1.6) activity and CAT mRNA in Norin61 were remarkably higher than in Shirogane-Komugi. Sensitivity to AsA at 35 and 42 DAPs kept high levels in Norin61, and endogenous AsA and CAT activity in the seeds were significantly higher than in Shirogane-Komugi. These results revealed a direct correlation between germination and antioxidant sensitivity during the developmental stages of wheat seeds.

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Ascorbate synthesis and ascorbate peroxidase activity during the early stage of wheat germination

Cited by 83 publications

References 27 publications

Buthionine sulfoximine (BSO)-mediated improvement in cultured embryo quality in vitro entails changes in ascorbate metabolism, meristem development and embryo maturation

Buthionine sulfoximine (BSO)-mediated improvement in cultured embryo quality in vitro entails changes in ascorbate metabolism, meristem development and embryo maturation

Dehydroascorbate Influences the Plant Cell Cycle through a Glutathione-Independent Reduction Mechanism

Hydrogen peroxide scavenging regulates germination ability during wheat (Triticum aestivumL.) seed maturation

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