The onset of cell proliferation is stimulated by ascorbate free radical in onion root primordia

Cabo, Rafael C De; González‐Reyes, José A.; Navas, Plácido

doi:10.1016/s0248-4900(05)80192-3

Cited by 22 publications

(8 citation statements)

References 18 publications

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“…ASC is a common compound in plants that may be physiologically involved in the regulation of cell-wall extensibility. Our group has published a number of observations that indicate that ASC and its free radical stimulate root elongation and accelerate the quiescence-proliferation transit in onion roots (Hidalgo et al, 1991;De Cabo et al, 1993;González-Reyes et al, 1994b), and similar results are shown in this paper. Onions grown in the presence of ASC had significantly longer roots than onions grown in control conditions; however, DHA inhibited cell elongation, supporting our previously reported data (González-Reyes et al, 1994a).…”

Section: Discussionsupporting

confidence: 85%

Role of Apoplastic and Cell-Wall Peroxidases on the Stimulation of Root Elongation by Ascorbate

et al. 1996

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Elongation of onion (Allium cepa L.) roots was highly stimulated by ascorbate (ASC) and its natural precursor I-galactone-y-lactone (CL). When incubation media were supplemented with lycorine (Lyc), an inhibitor of the ASC biosynthesis, root growth was negligible even in the presence of ASC or CL. ASC completely inhibited in vitro guaiacol peroxidase activities that were isolated from both the apoplast and the cell wall. However, ferulic-acid-dependent peroxidase from the cell wall was partially inhibited by ASC, whereas ferulic acid peroxidase activity from the apoplastic fluid was completely inhibited by ASC as long as ASC was present in the assay medium. ASC content in cells was increased by preincubations with ASC or CL, whereas Lyc reduced it. On the other hand, ASC or CL treatments decreased both apoplast and cell-wall-bound peroxidase activities, whereas Lyc had a slight stimulating effect. These results are discussed on the basis of a possible control of root elongation by ASC via its action on peroxidases that are involved in the regulation of cell-wall extensibility.ASC and its free radical AFR stimulate the elongation of onion (Allium cepa L.) roots in parallel to a high vacuolization of meristematic cells (Hidalgo et al., 1989;Navas, 1991;González-Reyes et al., 1994b). ASC is required for the progression of the G1 and G2 phases of the cell cycle (Liso et al., 1984). Current explanations for these observations include (a) the hyperpolarization of the plasma membrane and acidification of the apoplast induced by ASC and AFR (González-Reyes et al., 1992) after the activation of a plasmalemma NADH-AFR oxidoreductase activity that stimulates nutrient intake (Gonzalez-Reyes et al., 1994b), and (b) the maintenance, in a reduced state of Hyp-rich proteins, that is needed for the progression of the cell cycle (Arrigoni et al., 1977;De Gara et al., 1991a). Two recent reviews analyze these hypotheses in detail (Arrigoni, 1994; Cór-doba and González-Reyes, 1994).Root growth and elongation leads to an irreversible increase in cell volume. Thus, the cell-wall architecture is modified in such a way that a relaxation of the crossed bonds that link severa1 components of the cell wall must 95-0560).occur. Cell-wall loosening allows the increase of the cell surface and the intake of water by the protoplast, and changes in the cell-wall architecture during cell elongation have been recently reported (McCann and Roberts, 1994). Cell-wall-bound and/ or apoplastic peroxidases have been involved in the formation of isodityrosine bonds between glycoproteins as extensin, or diferulate bridges between polysaccharide polymers (Biggs and Fry, 1987). These peroxidase-driven cross-linking reactions of cellwall polymers stiffened the cell wall during growth, thus reducing the rate of elongation (Fry, 1986). To comprehend the regulation of cell-wall extensibility during growth, focus must be placed on the biological control of peroxidase activities at the cell wall. This includes the synthesis and secretion of peroxidases, the supp...

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Section: Discussionsupporting

confidence: 85%

Role of Apoplastic and Cell-Wall Peroxidases on the Stimulation of Root Elongation by Ascorbate

et al. 1996

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“…Therefore, the stimulation of root sprouting by ASC seems to depend on the ability of this 55 chemical to be oxidized during the incubation period. Since ASC stimulates neither elongation nor DNA synthesis in detached primordia (de Cabo et al 1993), ASC oxidation may depend on the environment within the basal plate rather than within the primordium itself. However, this possibility has to be investigated further.…”

Section: Discussionmentioning

confidence: 99%

Rooting hastened in onions by ascorbate and ascorbate free radical

Cabo

González-Reyes

Córdoba

et al. 1996

J Plant Growth Regul

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Treatment of onion bulbs with ascorbate or its free radical hastened root emergence on the basal plate in relation to treatments with water or dehydroascorbate. This stimulation was accompanied by a significant increase of DNA synthesis per primordium. After a 24-h imbibition, ascorbate and ascorbate free radical also increased cell length. Ascorbate and ascorbate free radical apparently activated the onset of cell proliferation in root primordia, resulting in a shortening in G1-S transition. The possible action of the ascorbate system at the plasma membrane level is discussed.

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“…; Castillo and Greppin 1988, Polle et al 1990, Luwe et al 1993, Luwe 1996, a role as oxygen radical scavenger has also been attributed to Asc in the extracellular matrix. In addition, extraceltular Asc strongly affects cell division (Cittero et al 1994, Navarro et al 1992, De Cabo et al 1993, celI growth (Gonzalez-Reyes et al 1994, Hidalgo et al 1991, and cell wall regeneration (Takahama and Oniki 1992). It is suggested that the control and regulation of the concentration and the redox status of Asc in the apoplast are important factors determining its physiological activity (Takahama and Oniki 1992).…”

Section: Introductionmentioning

confidence: 99%

Transport of ascorbate into protoplasts ofNicotiana tabacum Bright Yellow-2 cell line

et al. 1998

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Summary. The uptake of ascorbate into protoptasts isolated from aNicotiana tabacum Bright Yellow-2 (BY-2) cell suspension culture was investigated. Addition of ~4C-labelled ascorbate to freshly isolated protoplasts resulted in a time-and substrate-dependent association of radioactive molecules with the protoplasts. The kinetic characterisation of this presumptive uptake revealed kinetics of Michaelis-Menten type with an apparent maximal uptake activity of 24 pmol/min 9 106 protoplasts and an apparent affinity' constant of 139 gM. The amount of ascorbate molecules transported into N. tabacum protoplasts decreased when nonlabelled dehydroascorbate or iso-ascorbate were added but was not affected by addition of 5,6-o-cyctohexylidene ascorbate oi ascorbate-2-sulfate. These data indicate a carrier-mediated uptake of ascorbate into the protoplasts that shows a high structural specificity. To investigate which redox status of ascorbate is preferentially taken up by the N. tabacum protoplasts, transport was tested in the presence of various compounds that can affect the redox status of ascorbate. Testing uptake in the presence of a reductant, dithiothreitol, resulted in a signific3nt and concentration-dependent inhibition of the amount of ascorbate molecules transported into the protoplasts. On the other hand, ascorbate uptake was significantly stimulated in the presence of the enzyme ascorbate oxidase. Ferricyanide did not affect ascorbate transport. Inhibition studies revealed that ascorbate uptake in the protoplasts is sensitive to addition of sulflaydryl reagents N-ethyl maleimide and p-chloromercuribenzenesulfonic acid and to a disruption of the proton gradient by the protonophore carbonylcyanide-3-chlorophenylhydrazone. The uptake of ascorbate was also inhibited by addition of cyt0cha-Iasin B but not sensitive to addition of phtoretin or suIfinpyrazone. Taken together these data indicate the presence of an ascorbate transport system in the plasma membrane of N. tabacum protoplasts and suggest dehydroascorbate as the preferentially transported redox species. The putative presence of different carriers for reduced and oxidised ascorbate in the plasma membrane is discussed.

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The onset of cell proliferation is stimulated by ascorbate free radical in onion root primordia

Cited by 22 publications

References 18 publications

Role of Apoplastic and Cell-Wall Peroxidases on the Stimulation of Root Elongation by Ascorbate

Role of Apoplastic and Cell-Wall Peroxidases on the Stimulation of Root Elongation by Ascorbate

Rooting hastened in onions by ascorbate and ascorbate free radical

Transport of ascorbate into protoplasts ofNicotiana tabacum Bright Yellow-2 cell line

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