title: Identification of a homolog of Arabidopsis DSP4 (SEX4) in chestnut: its induction and accumulation in stem amyloplasts during winter or in response to the cold.
abstract: Oligosaccharide synthesis is an important cryoprotection strategy used by woody plants during winter dormancy. At the onset of autumn, starch stored in the stem and buds is broken down in response to the shorter days and lower temperatures resulting in the buildup of oligosaccharides. Given that the enzyme DSP4 is necessary for diurnal starch degradation in Arabidopsis leaves, this study was designed to address the role of DSP4 in this seasonal process in Castanea sativa Mill. The expression pattern of the CsDSP4 gene in cells of the chestnut stem was found to parallel starch catabolism. In this organ, DSP4 protein levels started to rise at the start of autumn and elevated levels persisted until the onset of spring. In addition, exposure of chestnut plantlets to 4 °C induced the expression of the CsDSP4 gene. In dormant trees or cold-stressed plantlets, the CsDSP4 protein was immunolocalized both in the amyloplast stroma and nucleus of stem cells, whereas in the conditions of vegetative growth, immunofluorescence was only detected in the nucleus. The studies indicate a potential role for DSP4 in starch degradation and cold acclimation following low temperature exposure during activity-dormancy transition.
authors.affiliation: Centro de Biotecnología y Genómica de Plantas UPM/INIA, Departamento de Biotecnología, E. T. S. Ingenieros de Montes, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, E-28223 Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Berrocal-Lobo
authors.forename: Cristian
authors.initials: C
authors.lastname: Ibañez
authors.forename: Paloma
authors.initials: P
authors.lastname: Acebo
authors.forename: Alberto
authors.initials: A
authors.lastname: Ramos
authors.forename: Estefania
authors.initials: E
authors.lastname: Perez-Solis
authors.forename: Carmen
authors.initials: C
authors.lastname: Collada
authors.forename: Rosa
authors.initials: R
authors.lastname: Casado
authors.forename: Cipriano
authors.initials: C
authors.lastname: Aragoncillo
authors.forename: Isabel
authors.initials: I
authors.lastname: Allona
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D003080:Cold Temperature; D018076:DNA, Complementary / Q000235:genetics; D054637:Dual-Specificity Phosphatases / Q000235:genetics / Q000378:metabolism; D029962:Fagaceae / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D018613:Microscopy, Confocal; D009844:Oligosaccharides / Q000378:metabolism; D017440:Photoperiod; D018515:Plant Leaves / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018547:Plant Stems / Q000201:enzymology / Q000235:genetics; D018087:Plastids / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics; D012621:Seasons; D036226:Seedlings / Q000235:genetics; D013213:Starch / Q000378:metabolism*; D013312:Stress, Physiological; D013997:Time Factors; D014197:Trees / Q000201:enzymology / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure
chemical_list: D018076:DNA, Complementary; D009844:Oligosaccharides; D010940:Plant Proteins; D018749:RNA, Plant; D013213:Starch; D054637:Dual-Specificity Phosphatases