Abiotic stress adversely affects the growth of grapevine plants. In order to study the early expression changes of genes particularly involved in signal transduction upon salt and drought stresses in grapevines, ESTs derived from a suppressive subtractive hybridization approach (SSH) were selected for expression studies. We were particularly interested in the expression behaviour of the MAP kinase cDNA clone identified by differential screening of the salt-stressed SSH libraries. Interestingly, VvMAP kinase transcript showed a differential expression towards salt and drought treatment in the salt tolerant cultivar Razegui. The upregulation of this transcript was confirmed by RNA blot analysis. Our results revealed that the VvMAP kinase gene could be classified as an osmotic stress responsive gene as its expression was induced by salinity and drought. Furthermore, our study provides the basis for future research on the diverse signaling pathways mediated by MAPKs in grapevine. 1. Introduction Salt and drought stresses are a severe constraint to crop production, and plants that undergo water deficit manifest a wide range of behaviors, ranging from high sensitivity to tolerance. Grapevine (V. vinifera L.) is economically important for Tunisian agriculture but, due to climate variability and environmental changes, yield and quality of the commonly grown grapevine varieties are impaired. Although the responses of plants to osmotic stress have been extensively studied at the physiological and biochemical levels, the perception and intracellular transmission mechanisms remain largely unknown. Due to their sessile habit, plants are exposed to a variety of environmental stresses. Thus, their responses and adaptation to environmental constraints must be communicated in a specific manner from outside of the cell to the inside, and ultimately to the nucleus, where changes in gene expression may occur. Therefore, plant adaptation to salinity requires the regulation of the expression of various genes which could encode for protein kinases and phospholipases, or transcription factors. Mitogen-activated protein kinases (MAPKs) are one of the important proteins involved in the signal transduction of extracellular information to intracellular targets and play a crucial role in the response to biotic and abiotic stresses [1]. Several plant protein kinases were found to be activated by osmotic stress [2]. It was shown that only one specific MAPK is activated by cold and drought stress in alfalfa plants (N6). Several MAP kinases were identified from different plant species
References
[1]
S. J. Neill and E. C. Burnett, “Regulation of gene expression during water deficit stress,” Plant Growth Regulation, vol. 29, no. 1-2, pp. 23–33, 1999.
[2]
J. K. Zhu, “Salt and drought stress signal transduction in plants,” Annual Review of Plant Biology, vol. 53, pp. 247–273, 2002.
[3]
K. Gomi, D. Ogawa, S. Katou et al., “A mitogen-activated protein kinase NtMPK4 activated by SIPKK is required for jasmonic acid signaling and involved in ozone tolerance via stomatal movement in tobacco,” Plant and Cell Physiology, vol. 46, no. 12, pp. 1902–1914, 2005.
[4]
M. Mayrose, A. Bonshtien, and G. Sessa, “LeMPK3 is a mitogen-activated protein kinase with dual specificity induced during tomato defense and wounding responses,” The Journal of Biological Chemistry, vol. 279, no. 15, pp. 14819–14827, 2004.
[5]
L. B？gre, W. Ligterink, I. Meskiene et al., “Wounding induces the rapid and transient activation of a specific MAP kinase pathway,” Plant Cell, vol. 9, no. 1, pp. 75–83, 1997.
[6]
M. Lalle, S. Visconti, M. Marra, L. Camoni, R. Velasco, and P. Aducci, “ZmMPK6, a novel maize MAP kinase that interacts with 14-3-3 proteins,” Plant Molecular Biology, vol. 59, no. 5, pp. 713–722, 2005.
[7]
D. Takezawa, “Elicitor- and A23187-induced expression of WCK-1, a gene encoding mitogen-activated protein kinase in wheat,” Plant Molecular Biology, vol. 40, no. 6, pp. 921–933, 1999.
[8]
M. L. W. Knetsch, M. Wang, B. Ewa Snaar-Jagalska, and S. Heimovaara-Dijkstra, “Abscisic acid induces mitogen-activated protein kinase activation in barley aleurone protoplasts,” Plant Cell, vol. 8, no. 6, pp. 1061–1067, 1996.
[9]
T. K. Hyun, J. S. Kim, S. Y. Kwon, and S. H. Kim, “Comparative genomic analysis of mitogen activated protein kinase gene family in grapevine,” Genes and Genomics, vol. 32, no. 3, pp. 275–281, 2010.
[10]
G. P. Chen, W. S. Ma, Z. J. Huang, T. Xu, Y. B. Xue, and Y. Z. Shen, “Isolation and characterization of TaGSK1 involved in wheat salt tolerance,” Plant Science, vol. 165, no. 6, pp. 1369–1375, 2003.
[11]
F. Cellier, G. Conéjéro, J. C. Breitler, and F. Casse, “Molecular and physiological responses to water deficit in drought-tolerant and drought-sensitive lines of sunflower,” Plant Physiology, vol. 116, no. 1, pp. 319–328, 1998.
[12]
L. Hamrouni, F. Ben Abdallah, C. Abdelly, and A. Ghorbel, “Evaluation de la tolérance au sel chez les vignes tunisiennes cultivées in vitro,” in Poceedings du XXVIIème Congrès Mondial de la Vigne et du Vin, pp. 102–112, Bratislava, Slovakia, June 2002.
[13]
I. Toumi, M. Gargouri, I. Nouairi et al., “Water stress induced changes in the leaf lipid composition of four grapevine genotypes with different drought tolerance,” Biologia Plantarum, vol. 52, no. 1, pp. 161–164, 2008.
[14]
I. Toumi, P. N. Moschou, K. A. Paschalidis et al., “Abscisic acid signals reorientation of polyamine metabolism to orchestrate stress responses via the polyamine exodus pathway in grapevine,” Journal of Plant Physiology, vol. 167, no. 7, pp. 519–525, 2010.
[15]
S. Daldoul, S. Chenenanoui, A. Mliki, and M. H？fer, “Improvement of an RNA purification method for grapevine (Vitis vinifera L.) suitable for cDNA library construction,” Acta Physiologiae Plantarum, vol. 31, no. 4, pp. 871–875, 2009.
[16]
S. Daldoul, S. Guillaumie, G. M. Reustle et al., “Isolation and expression analysis of salt induced genes from contrasting grapevine (Vitis vinifera L.) cultivars,” Plant Science, vol. 179, no. 5, pp. 489–498, 2010.
[17]
S. F. Altschul, W. Gish, W. Miller, E. W. Myers, and D. J. Lipman, “Basic local alignment search tool,” Journal of Molecular Biology, vol. 215, no. 3, pp. 403–410, 1990.
[18]
H. J. Bohnert and J. C. Cushman, “Plant and environmental stress adaptation strategies,” in Plant Biotechnology and Transgenic Plants, K.-M. Oksman-Caldentey and W. H. Barz, Eds., pp. 635–664, Marcel Dekker, New York, NY, USA, 2002.
[19]
R. Munns, “Comparative physiology of salt and water stress,” Plant, Cell and Environment, vol. 25, no. 2, pp. 239–250, 2002.
[20]
L. Xiong and Y. Yang, “Disease resistance and abiotic stress tolerance in rice are inversely modulated by an abscisic acid-inducible mitogen-activated protein kinase,” Plant Cell, vol. 15, no. 3, pp. 745–759, 2003.
[21]
C. Jonak, S. Kiegerl, W. Ligterink, P. J. Barker, N. S. Huskisson, and H. Hirt, “Stress signaling in plants: a mitogen-activated protein kinase pathway is activated by cold and drought,” Proceedings of the National Academy of Sciences of the United States of America, vol. 93, no. 20, pp. 11274–11279, 1996.
[22]
B. P？pping, T. Gibbons, and M. D. Watson, “The Pisum sativum MAP kinase homologue (PsMAPK) rescues the Saccharomyces cerevisiae hog1 deletion mutant under conditions of high osmotic stress,” Plant Molecular Biology, vol. 31, no. 2, pp. 355–363, 1996.
