Isolation and Characterization of Expansin Genes in a Halophyte, Suaeda japonica

칠면초(Suaeda japonica) expansin 유전자의 분리 및 특성 분석

  • 황숭택 (국립군산대학교 자연과학대학 생물학과) ;
  • 김석규 (국립군산대학교 자연과학대학 생물학과) ;
  • 나종길 (국립군산대학교 자연과학대학 생물학과) ;
  • 이점숙 (국립군산대학교 자연과학대학 생물학과) ;
  • 최동수 (국립군산대학교 자연과학대학 생물학과)
  • Received : 2012.11.30
  • Accepted : 2012.12.17
  • Published : 2013.02.28


Halophytes are unique land plants that are capable of thriving in a high-salt environment. They are attracting public attention due to their ability to synthesize bioactive substances such as UV protectants or antioxidizing agents. To achieve unaffected growth under high salinity, halophytes may take advantage of the activities of cell growth factors such as expansins. Expansins are well-known cell wall proteins that are responsible for cell enlargement. They loosen cell walls, thereby contributing to actual plant growth. This study aimed to identify positive roles of expansins in the growth of halophytes. Three expansin cDNA clones were isolated from seedlings of Suaeda japonica. Comparing the deduced amino acid sequences of the expansin genes of S. japonica with those of other plant species suggested that the cDNA clones isolated from S. japonica belong to the EXPA (${\alpha}$-expansin) gene family. A phylogenetic tree based on the deduced amino acid sequences revealed that the expansins of S. japonica share a close evolutionary relationship with those of strawberry (Fragaria ananassa) and jujube (Ziziphus jujuba), both of which are woody dicots. SjEXPAs did not show any remarkable change in the gene expression level in different NaCl concentrations, providing a clue to the unaffected seedling growth of S. japonica in a high-salt environment. In conclusion, the present study presents the first report of expansin genes from halophytes and suggests a putative role for these genes in plant growth under high salinity.


Supported by : 한국연구재단


  1. Anjanasree, K. N. and Bansal, K. C. 2003. Isolation and characterization of ripening-related expansin cDNA from tomato. J Plant Biochem Biotechnol 12, 31-35.
  2. Cho, H. T. and Cosgrove, D. J. 2002. Regulation of root hair initiation and expansin gene expression in Arabidopsis. Plant Cell 14, 3237-3253.
  3. Cho, H. T. and Cosgrove, D. J. 2004. Expansins as agents in hormone action. pp. 262-281. In Davies, P. J. (ed.), Plant Hormones 3rd edn. Kluwer Academic, Dordrecht.
  4. Cho, H. T. and Kende, H. 1997a. Expansins in deepwater rice inter-nodes. Plant Physiol 113, 1137-1143.
  5. Cho, H. T. and Kende, H. 1997b. Expansins and internodal growth of deepwater rice. Plant Physiol 113, 1145-1151.
  6. Cho, H. T. and Kende, H. 1997c. Expression of expansin genes is correlated with growth in deepwater rice. Plant Cell 9, 1661-1671.
  7. Choi, D., Cho, H. T. and Lee, Y. 2006. Expansins: expanding importance in plant growth and development. Plant Physiol 126, 511-518.
  8. Choi, D. 2007. Ethylen-induced stem growth of deepwater rice is correlated with expression of gibberellin- and abscisic acid-biosynthetic genes. J Plant Biol 50, 595-599.
  9. Choi, J. I., Kim, Y. J., Kim, J. H., Song, B. S., Yoon, Y., Byun, M. W., Kwon, J. H., Chun, S. S. and Lee, J. W. 2009. Antioxidant activities of the extract fractions from Suaeda japonica. J Korean Soc Food Sci Nutr 38, 131-135.
  10. Cosgrove, D. J. 1998. Cell wall loosening by expansins. Plant Physiol 118, 333-339.
  11. Cosgrove, D. J. 2000. Loosening of plant cell walls by expansins. Nature 407, 321-326.
  12. Gao, X., Liu, K. and Lu, Y. T. 2010. Specific roles of AtEXPA1 in plant growth and stress adaptation. Russ. J Plant Physiol 57, 241-246.
  13. Hiwasa, K., Rose, J. K. C., Nakano, R., Inaba, A. and Kubo, Y. 2003. Differential expression of seven alpha-expansin genes during growth and ripening of pear fruit. Plant Physiol 117, 564-572.
  14. Kende, H., Bradford, K., Brummell, D., Cho, H. T., Cosgrove, D. J., Fleming, A., Gehring, C., Lee, Y., McQueen-Mason, S. M., Rose, J. K. C. and Voesenek, L. A. 2004. Nomenclature for members of the expansin superfamily of genes and proteins. Plant Mol Biol 55, 311-314.
  15. Kim, J. H., Cho, H. T. and Kende, H. 2000. ${\alpha}$-Expansins in the semiaquatic ferns Marsilea Quadrifolia and Regnellidium diphyllum: evolutionary aspects and physiological role in rachis elongation. Planta 212, 85-92.
  16. Kim, Y. A., Um, Y. R., Lee, J. I., Kim, H. J., Lim, S. Y., Nam, T. J. and Seo, Y. W. 2009. Comparative studies on the fatty acid compositions of the korean salt marsh plants in the west sea. Korean J Biotechnol Bioeng 24, 521-526.
  17. Lee, D. K., Ahn, J. H., Song, S. K., Choi, Y. D. and Lee, J. S. 2003. Expression of an expansin gene is correlated with root elongation in soybean. Plant Physiol 131, 985-997.
  18. Lee, H. J., Kim, Y. A., Ahn, J. W., Lee, B. J., Moon, S. G. and Seo, Y. 2004. Screening of peroxynitrite and DPPH radical scavenging activities from salt marsh plants. Korean J Biotechnol Bioeng 19, 57-61.
  19. Lee, Y., Choi, D. and Kende, H. 2001. Expansins: ever-expanding numbers and functions. Curr Opin Plant Biol 2001 4, 527-532.
  20. Lee, Y. and Kende, H. 2002. Expression of alpha-expansin and expansin-like genes in deepwater rice. Plant Physiol 130, 1396-1405.
  21. Min, B. M. 1998. Vegetation on the west coast of Korea. Ocean Polar Res 20, 167-178.
  22. Mim, B. M. 2005. Seed distribution and burial properties of Suaeda japonica in tidal-flat. J Ecol Field Biol 28, 141-147.
  23. Mühling, K. H. and Lauchli, A. 2002. Effect of salt sterss on growth and cation compartmentation in leaves of two plant species differing in salt tolerance. Plant Physiol 159, 137-146.
  24. Pitann, B., Zorb, C. and Mühling, K. H. 2009. Comparetive proteome analysis of maize (Zea mays L.) expansins under salinity. J Plant Nutr Soil Sci 172, 75-77.
  25. Rose, J. K. C., Lee, H. H. and Bennett, A. B. 1997. Expression of a divergent expansin gene is fruit-specific and ripening- regulated. Proc Natl Acad Sci USA 94, 5955-5960.