Functional characterization of an acidic SK3 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.

The Importance of Size and Disorder in the Cryoprotective Effects of Dehydrins

“…Because of this, the insertion process could be repeated to create the K 6 , K 8 , and K 10 protein constructs. The expression and purification of the K n proteins was performed identically to that described for K 2 (Livernois et al, 2009 [Wisniewski et al, 1999]; Thellungiella salsuginea dehydrin (TsDHN-2) from G. Harauz, University of Guelph [Rahman et al, 2010]; barley (Hordeum vulgare) dehydrin (Dhn5) from T.J. Close, University of California, Riverside [Bravo et al, 1999]; and Opuntia streptacantha dehydrin (OpsDHN-1) from J.-F. Jiménez Bremont, Instituto Potosino de Investigación Científica y Tecnológica, San Luis Potosi, Mexico [Ochoa-Alfaro et al, 2012]) and were expressed and purified as described for K 2 . The expression and purification of Vitis riparia YSK 2 has been described previously (Livernois et al, 2009).…”

Protein Profiles and Dehydrin Accumulation in Some Soybean Varieties (<i>Glycine max</i> L. Merr) in Drought Stress Conditions

“…This indicates that tolerance to drought stress was among others, controlled by the amount of dehydrin accumulated during the stress as has been reported in some experiment in plants [4,7,33]. Several transgenic plants shows overexpression of the gene codes dehydrin synthesis [34][35][36][37].…”

The Opuntia streptacantha OpsHSP18 Gene Confers Salt and Osmotic Stress Tolerance in Arabidopsis thaliana

“…HO058719) encoding a small heat shock protein (OpsHSP18) from Opuntia streptacantha was isolated from a cDNA library previously generated under stress conditions [24]. The cDNA sequence comprises a 5′-UTR region of 95 bp, a 3′-UTR region of 221 bp, and an open reading frame (ORF) of 486 bp encoding a polypeptide of 161 amino acids with a predicted molecular mass of 18.34 kDa and an isoelectric point (pI) of 5.85 (Figure S1).…”

“…Recently, our research group generated a cDNA library from Opuntia streptacantha plants under abiotic stress conditions [24]. Among 329 unigenes of this cDNA library, 9% (29 unigenes) were involved in stress responsiveness, such as the heat shock proteins: HSP90, HSP70, HSP40, and sHSP.…”

“…Recently, our group reported a cDNA library of Opuntia streptacantha cladodes containing a collection of ESTs accumulated under abiotic stress [24]. Among the genes involved in stress response obtained in this library, a small heat shock protein (sHSP) was identified.…”