Connecting sulfur metabolism and salt tolerance mechanisms in the halophytes Aster tripolium and Sesuvium portulacastrum

Our aim of research is to investigate the role of sulfolipids and enzymes involved in sulfur metabolism in salt tolerance. Sulfolipids occur in the plastid membrane and are probably necessary for proper function of the plastidic ATPase. Two halophytes were chosen for a detailed analysis: Aster tripolium L. and Sesuvium portulacastrum L. Plants were watered for up to 10 days with solutions containing different NaCl concentrations. Plant extracts were analysed for sulfolipid contents and enzyme activity. The sulfolipid contents analysed by thin layer chromatography were always enhanced in Aster leaves when watered with NaCl solutions whereas in Sesuvium leaves the sulfolipid contents were only slightly increased at higher salt concentrations. After salt treatment for 10 days the enzymatic formation of L-cysteine and of β-cyanoalanine was drastically reduced in Aster leaves and roots. In diverse species the sulfolipid synthesis is expressed in different ways following different salt tolerance mechanisms.