An osmotin-like cryoprotective protein from the bittersweet nightshade Solanum dulcamara
- 144 Downloads
Cold acclimation in plants is a polygenic phenomenon involving increased expression of several genes. The gene products participate either directly or indirectly towards increasing cold tolerance. Evidence of proteins having a direct effect on cold tolerance is emerging but limited. With isolated protoplasts from warm-grown kale (Brassica oleracea) as a model system, we tested protein fractions from winter bittersweet nightshade, Solanum dulcamara, stems for the presence of proteins that have a cryoprotective effect. Purification of one such fraction resulted in isolation of a 25 kDa protein. N-terminal Edman degradation amino acid sequence analysis showed that it has high homology to osmotin and osmotin-like proteins. When added to warm-grown protoplasts, it increased the cryosurvival of frozen-thawed protoplasts by 24% over untreated or BSA-treated controls at −8 °C. A cDNA library which was made in November from stems and leaves of S. dulcamara was successfully screened for the corresponding cDNA clone. The deduced amino acid sequence indicated that the protein consists of 206 amino acid residues including a N-terminal signal sequence and a putative C-terminal propeptide. The mature protein, without the N-terminal signal sequence, was expressed in Escherichia coli. The partially purified protein in the supernatant fraction of the culture medium had cryoprotective activity.
Unable to display preview. Download preview PDF.
- Hincha, D.K., Heber, U. and Schmitt, J.M. 1989. Freezing ruptures thylakoid membranes in leaves, and rupture can be prevented in vitro by cryoprotective proteins. Plant Physiol. Biochem. 27: 795–801.Google Scholar
- Hincha, D.K., Heber, U. and Schmitt, J.M. 1990. Proteins from frost-hardy leaves protect thylakoids against mechanical freezethaw damage in vitro. Planta 180: 416–419.Google Scholar
- Marentes, E., Griffith, M., Mlynarz, A. and Brush, R.A. 1993. Proteins accumulate in the apoplast of winter rye leaves during cold acclimation. Plant Physiol. 87: 499–507.Google Scholar
- Melchers, L.S., Sela-Buurlage, M.B., Vloemans, S.A., Woloshuk, C.P., van Roekel, J.S., Pen, J., van den Elzen, P.J. and Cornelissen, B.J. 1993. Extracellular targeting of the vacuolar tobacco proteins AP24, chitinase and β-1,3-glucanase in transgenic plants. Plant Mol. Biol. 21: 583–593.PubMedGoogle Scholar
- Rosas, A., Alberdi, M., Delseny, M. and Meza-Basso, L. 1986. A cryoprotective polypeptide isolated from Northofagus dombeyi seedlings. Phytochemistry 25: 2497–2500.Google Scholar
- Singh, N.K., Bracker, C.A., Hasegawa, P.A., Handa, A.K., Buckel, S., Hermodson, M.A., Pfankoch, E., Regnier, F.E. and Bressan, R.A. 1987. Characterization of osmotin. Plant Physiol 85: 529–536.Google Scholar
- Thomashow, M.F. 1990. Molecular genetics of cold acclimation in higher plants. Adv. Genet. 67: 478–483.Google Scholar
- Thomashow, M.F., Gilmour, S.J. and Lin, C. 1993. Cold-regulated genes of Arabidopsis thaliana. In: P.H. Li and L. Christersson (Eds.) Advances in Plant Cold Hardiness, CRC Press, Boca Raton, FL, pp. 31–44.Google Scholar
- Weist, S.C. and Steponkus, P.L. 1978. Freeze-thaw injury to isolated spinach protoplasts and its simulation at above freezing temperatures. Plant Physiol. 62: 699–705.Google Scholar
- Yun, D.J., Bressan, R.A. and Hasegawa, P.M. 1997. Plant antifungal proteins. In: J. Janick (Ed.) Plant Breeding Reviews, Wiley, New York, pp. 39–88.Google Scholar