Involvement of polyamine oxidase in wound healing.
Hydrogen peroxide (H(2)O(2)) is involved in plant defense responses that follow mechanical damage, such as those that occur during herbivore or insect attacks, as well as pathogen attack. H(2)O(2) accumulation is induced during wound healing processes as well as by treatment with the wound signal jasmonic acid. Plant polyamine oxidases (PAOs) are H(2)O(2) producing enzymes supposedly involved in cell wall differentiation processes and defense responses. Maize (Zea mays) PAO (ZmPAO) is a developmentally regulated flavoprotein abundant in primary and secondary cell walls of several tissues. In this study, we investigated the effect of wounding on ZmPAO gene expression in the outer tissues of the maize mesocotyl and provide evidence that ZmPAO enzyme activity, protein, and mRNA levels increased in response to wounding as well as jasmonic acid treatment. Histochemically detected ZmPAO activity especially intensified in the epidermis and in the wound periderm, suggesting a tissue-specific involvement of ZmPAO in wound healing. The role played by ZmPAO-derived H(2)O(2) production in peroxidase-mediated wall stiffening events was further investigated by exploiting the in vivo use of N-prenylagmatine (G3), a selective and powerful ZmPAO inhibitor, representing a reliable diagnostic tool in discriminating ZmPAO-mediated H(2)O(2) production from that generated by peroxidase, oxalate oxidase, or by NADPH oxidase activity. Here, we demonstrate that G3 inhibits wound-induced H(2)O(2) production and strongly reduces lignin and suberin polyphenolic domain deposition along the wound, while it is ineffective in inhibiting the deposition of suberin aliphatic domain. Moreover, ZmPAO ectopic expression in the cell wall of transgenic tobacco (Nicotiana tabacum) plants strongly enhanced lignosuberization along the wound periderm, providing evidence for a causal relationship between PAO and peroxidase-mediated events during wound healing.
Angelini
Riccardo
R
Dipartimento di Biologia, Università Roma Tre, Viale G Marconi 446, 00146, Rome, Italy.
Tisi
Alessandra
A
Rea
Giuseppina
G
Chen
Martha M
MM
Botta
Maurizio
M
Federico
Rodolfo
R
Cona
Alessandra
A
D000376:Agmatine / Q000031:analogs & derivatives / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology*; D006861:Hydrogen Peroxide; D008031:Lignin / Q000096:biosynthesis; D008055:Lipids / Q000235:genetics; D019255:NADPH Oxidases / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics / Q000378:metabolism*; D054883:Oxylipins / Q000494:pharmacology; D009195:Peroxidase / Q000378:metabolism; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified; D017434:Protein Structure, Tertiary; D017382:Reactive Oxygen Species / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects / Q000201:enzymology*; D000097667:Polyamine Oxidase
D000376:Agmatine; D003517:Cyclopentanes; D006861:Hydrogen Peroxide; D008031:Lignin; D008055:Lipids; D019255:NADPH Oxidases; D010088:Oxidoreductases; D000587:Oxidoreductases Acting on CH-NH Group Donors; D054883:Oxylipins; D009195:Peroxidase; D017382:Reactive Oxygen Species; D020156:Salicylic Acid; D000097667:Polyamine Oxidase; C514183:N-prenylagmatine; C011006:jasmonic acid; C065875:suberin; C020598:oxalate oxidase