title: Desiccation tolerance of the resurrection plant Ramonda serbica is associated with dehydration-dependent changes in levels of proteolytic activities.
abstract: The unique response of desiccation-tolerant, or resurrection plants, to extreme drought is accompanied by major changes in the protein pool, raising the possibility of the involvement of proteases. We detected and characterized proteases present in their active state in leaf extracts of desiccated Ramonda serbica Panč., a resurrection plant from the Balkan Peninsula. Plants desiccated under laboratory conditions and maintained in anhydrobiosis for 4 and 14 months revived upon rehydration. Protease activities were determined spectrophotometrically in solution and by zymography on gels. Several endo- and aminopeptidases were detected and characterized by their pH profiles. Their enzyme class was determined using specific inhibitors. Those with higher activities were a serine endopeptidase active against Bz-Arg-pNA with a pH optimum around 9, and aminopeptidases optimally active at pHs from 7 to 9 against Leu-pNA, Met-pNA, Phe-pNA, Pro-pNA and Ala-pNA. The levels of their activities in leaf extracts from desiccated plants were significantly higher than those from rehydrated plants and from regularly watered plants, implying their involvement in the recovery of vegetative tissues from desiccation.
authors: Department of Biotechnology, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia. Electronic address: marjetka.kidric@ijs.si.
authors: Marjetka
authors: M
authors: Kidrič
authors: Department of Biotechnology, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia.
authors: Jerica
authors: J
authors: Sabotič
authors: Institute of Botany and Botanical Garden, Department of Plant Ecology and Phytogeography, Faculty of Biology, University of Belgrade, Takovska 43, 11000 Belgrade, Serbia.
authors: Branka
authors: B
authors: Stevanović
mesh_terms: D000222:Adaptation, Physiological; D000626:Aminopeptidases / Q000378:metabolism; D032181:Craterostigma / Q000201:enzymology / Q000502:physiology*; D003890:Desiccation; D010936:Plant Extracts / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000502:physiology; D059748:Proteolysis
chemical_list: D010936:Plant Extracts; D000626:Aminopeptidases
keywords: Aminopeptidase; Desiccation tolerance; Ramonda serbica; Resurrection plants; Serine endopeptidase