High flexibility in growth and polyamine composition of the crucifer Pringlea antiscorbutica in relation to environmental conditions

Abstract

Although polyamine (PA) metabolism in plants responds to abiotic stresses, few studies have investigated this response in plants under natural conditions. Using high-performance liquid chromatography, we studied the amine composition of the subantarctic crucifer Pringlea antiscorbutica R. Br. both in the field (Crozet and Kerguelen Islands) and under controlled temperatures in the laboratory. Plants collected from different sites showed a large variability of amine composition and contents. The aliphatic and acetylated amine composition of leaves allowed to statistically identify two groups. The first group, composed of Kerguelen coastal plants, was characterized by high levels of acetylspermidine and acetylspermine, showing the presence in P. antiscorbutica of this uncommon regulation pathway. PA acetylation may be induced in P. antiscorbutica under conditions of low water availability. The second group, composed of plants from Kerguelen altitude sites and plants from Crozet sites, showed high levels of free spermidine (Spd). In these plants, the ratio Spd/putrescine did not positively correlate with plant size as was found in developmental studies, suggesting that free Spd may be devoted to other aims, such as cold tolerance. Some differences between Crozet and Kerguelen plant responses suggested the possibility that different regulations of amine metabolism could take place in plants from these two islands. Agmatine accumulation pattern was diverse and suggested this amine to be sensitive to combinations of environmental factors. Studies on amine variation patterns in P. antiscorbutica provide insights into the roles of rarely reported amines, such as acetylated amines, in plant metabolic adaptation to abiotic stresses. Copyright © Physiologia Plantarum 2006.