title: Functional characterization of an acidic SK(3) dehydrin isolated from an Opuntia                      streptacantha cDNA library.
abstract: Cactus pears are succulent plants of the Cactaceae family adapted to extremely arid, hot and cold environments, making them excellent models for the study of molecular mechanisms underlying abiotic stress tolerance. Herein, we report a directional cDNA library from 12-month-old cladodes of Opuntia streptacantha plants subjected to abiotic stresses. A total of 442 clones were sequenced, representing 329 cactus pear unigenes, classified into eleven functional categories. The most abundant EST (unigen 33) was characterized under abiotic stress. This cDNA of 905 bp encodes a SK(3)-type acidic dehydrin of 248 amino acids. The OpsDHN1 gene contains an intron inserted within the sequence encoding the S-motif. qRT-PCR analysis shows that the OpsDHN1 transcript is specifically accumulated in response to cold stress, and induced by abscisic acid. Over-expression of the OpsDHN1 gene in Arabidopsis thaliana leads to enhanced tolerance to freezing treatment, suggesting that OpsDHN1 participates in freezing stress responsiveness. Generation of the first EST collection for the characterization of cactus pear genes constitutes a useful platform for the understanding of molecular mechanisms of stress tolerance in Opuntia and other CAM plants.
authors: Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa de San Jose 2055, Apartado Postal 3-74 Tangamanga, CP 78216 San Luis Potosi, SLP, Mexico.
authors: A E
authors: AE
authors: Ochoa-Alfaro
authors: M
authors: M
authors: Rodríguez-Kessler
authors: M B
authors: MB
authors: Pérez-Morales
authors: P
authors: P
authors: Delgado-Sánchez
authors: C L
authors: CL
authors: Cuevas-Velazquez
authors: G
authors: G
authors: Gómez-Anduro
authors: J F
authors: JF
authors: Jiménez-Bremont
mesh_terms: D003080:Cold Temperature; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D015723:Gene Library; D029747:Opuntia / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins