Polyamines (PAs), low molecular mass polycations, are ubiquitous cell components that are essential for normal growth of both eukaryotic and prokaryotic cells. Most of the biological functions of PAs can be explained by their polycationic nature, which facilitates interactions with anionic macromolecules (such as DNA and RNA) and negatively charged groups of membranes. They are implicated in a wide range of biological processes including cell division and growth, morphogenesis and differentiation and responses to biotic and abiotic stresses. The most abundant PAs in plants are putrescine (Put), spermidine (Spd) and spermine (Spm).
Put is formed either by direct decarboxylation of ornithine by the enzyme ornithine decarboxylase (ODC) or by decarboxylation of arginine by arginine decarboxylase (ADC) via agmatine and N-carbomoyl-putrescine intermediates. S-adenosylmethionine decarboxylase (SAMDC) is essential for the production of the aminopropyl group used in the biosynthesis of Spd and Spm. Apart from PA biosynthesis, the intracellular concentrations of free PAs could be maintained by conjugation with hydroxycinnamic acids (HCAA) and by PA degradation through oxidative deamination (CuAO, PAO).
Our lab study the role of polyamine and their metabolism during process of somatic embryogenesis, in connection with biotic and abiotic stresses and in autophagy.
ADC, arginine decarboxylase; AIH, agmatine imino hydroxylase; AtPAO1, Arabidopsis thaliana polyamine oxidase 1; Cad, cadaverine; CuAO, copper amine oxidase; CPA, N-carbamoylputrescine amidohydrolase; dcSAM, decarboxylated S-adenosyl-l-methionine; GABA, γ-aminobutyric acid; HCAA, hydroxycinnamic acid amide; HCT, hydroxycinnamoyl transferase; LDC, lysine decarboxylase MPO, N-methyl-putrescine oxidase; ODC, ornithine decarboxylase; PAO, polyamine oxidase (per, peroxisomal; ex, extracellular); SAM, S-adenosyl-l-methionine; Spd, spermidine; Spm, spermine; PMT, putrescine N-methyl transferase; Put, putrescine; SAMDC, S-adenosyl-l-methionine decarboxylase; SPDS, spermidine synthase; SPMS, spermine synthase; T-Spm, thermospermine; TSPMS, thermospermine synthase.