De-etiolation causes a phytochrome-mediated increase of polyamine oxidase expression in outer tissues of the maize mesocotyl: a role in the photomodulation of growth and cell wall differentiation

Abstract

The photomodulation of polyamine oxidase (PAO) expression during de-etiolation of the maize (Zea mays L.) mesocotyl was used as the experimental model to investigate a possible correlation with the photomodulation of growth and with wall dierentiation and stiening. The accumulation of PAO transcript and enzyme activity were enhanced by light treatment in cortical and epidermal (outer) tissues of the mesocotyl. Histochemical analysis revealed that this phenomenon is mostly due to the increased level of PAO activity in epidermal and sub-epidermal tissues. The photomodulation of PAO activity upon de-etiolation in outer tissues is mediated by phytochrome. A close correlation was found between the time course of red-light-elicited increase of PAO activity and that of growth inhibition in the outer tissues of the apical, growing zone of the mesocotyl. Light exposure of etiolated, sub-apical mesocotyl segments resulted in a higher production of hydrogen peroxide (H 2 O 2 ) in the incubation medium compared with segments incubated in the dark. The latter phenomenon was inhibited by the speci®c PAO inhibitor guazatine. A short pre-treatment of mesocotyl and coleoptile segments with 1 mM spermidine inhibited IAA-induced elongation growth, this phenomenon being reversed by catalase. Pre-treatment with catalase alone resulted in a higher extent of IAA-induced elongation. Moreover, pre-incubation with 1,3-diaminopropane, a product of spermidine oxidation catalysed by PAO, had no eect on IAA-induced elongation growth of either coleoptile or mesocotyl segments, while H 2 O 2 pre-treatment was eective. These results indicate that PAO activity is important in producing H 2 O 2 in vivo for peroxidase-catalysed wall-stiening reactions and may be involved in the modulation of growth and cell wall dierentiation in the maize mesocotyl.Key words: Cell wall stiening ± Hydrogen peroxide ± Mesocotyl growth and phytochrome ± Peroxidase ± Polyamine oxidase ± Programmed cell death ± Zea (cell wall stiening)Abbreviations: AAP = 4-aminoantipyrine; DCHBS = 3,5-dichloro-2-hydroxybenzene sulfonic acid; PAO = polyamine oxidase; PCD = programmed cell death

Heterologous Expression and Characterization of Mouse Spermine Oxidase

“…As compared with large and detailed investigations on plant PAOs (1,(13)(14)(15)(16)(17)(18)(19)(20)(21)(22), only little attention has been devoted to the animal counterpart (2,(23)(24)(25)(26)(27)(28). Recently, Wang et al (29) and Vujcic et al (30) have reported the cloning and characterization of novel mammalian PAO enzymes capable of oxidizing preferentially Spm and for this reason named spermine oxidase (SMO) (30).…”

Sites and Regulation of Polyamine Catabolism in the Tobacco Plant. Correlations with Cell Division/Expansion, Cell Cycle Progression, and Vascular Development

“…We have thoroughly studied intra-and extracellular H 2 O 2 and O 2 .2 generation, accumulation, and scavenging in plant protoplasts (Siminis et al, 1994;de Marco and Roubelakis-Angelakis, 1996;Roubelakis-Angelakis, 1999, 2005;Papadakis et al, 2001). H 2 O 2 generation in the apoplast can be ascribed to oxalate oxidases, O 2 .2 dismutation (Papadakis et al, 2001), peroxidases (POXs; de Marco and Roubelakis- Angelakis, 1996), or amine oxidases (Laurenzi et al, 1999;Sebela et al, 2001;Rea et al, 2002;Papadakis and Roubelakis-Angelakis, 2005). H 2 O 2 produced by the action of diamine oxidases (DAOs) and PA oxidases (PAOs) can be utilized by POX enzymes in wallstiffening reactions during cell growth and differentiation (Wisniewski et al, 2000).…”

“…Investigations on PA physiological functions have been focused mainly on changes in their levels and spectra, leaving the biological significance to be determined. Although genetic analyses have been conducted at the gene level (Laurenzi et al, 1999;Sebela et al, 2001;Rea et al, 2002;Papadakis and Roubelakis-Angelakis, 2005). H 2 O 2 produced by the action of diamine oxidases (DAOs) and PA oxidases (PAOs) can be utilized by POX enzymes in wallstiffening reactions during cell growth and differentiation (Wisniewski et al, 2000).…”

Dimethylthiourea, a hydrogen peroxide trap, partially prevents stress effects and ascorbate peroxidase increase in spermidine-treated maize roots

“…This appears consistent with findings of several authors on the involvement of hydrogen peroxide in the cell wall stiffening processes and in lignin biosynthesis as a substrate for peroxidases present in the apoplast (Federico & Angelini 1986 + RNA were loaded per lane, transferred onto a Hybond N + membrane (Amersham), hybridized with 32 Plabelled cDNA cytosolic APX probe and autoradiographed as described in 'Materials and Methods'. (b), Densitometric analysis of expression levels observed in section A, with respect to SPD 3 h designated 100% (1, control 3 h; 2, spermidine 3 h; 3, controlRobertsen 1993; Laurenzi et al 1999) and with the early differentiation of the cells in the elongation zone revealed in maize roots by both histological observation and cell-shape analysis along the root growth axis (de Agazio et al 1995a). The incomplete reduction of the spermidine-inhibiting effect of maize root growth by DMTU, reported in Table 1, can be ascribed to an incomplete removal of H 2 O 2 by DMTU.…”

“…The reactive oxygen species (ROS), including H 2 O, are responsible for the oxidative stress. As hydrogen peroxide is a product of polyamine catabolism, earlier authors correlated phenomenon such as programmed cell death in animal cells (Ha et al 1997) or cell wall differentiation in maize mesocotyl (Laurenzi et al 1999) to an increase of PAO activity. On the other hand generation of ROS, particularly H 2 O 2 , during abiotic stresses, has also been proposed as part of the signalling cascade leading to protection from these stresses (Prasad et al 1994;Foyer et al 1997).…”