Journal of Plant Biotechnology

The Korean Society of Plant Biotechnology (한국식물생명공학회)
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Metabolic Study on C29-Brassinosteroids in Young Rice Plants

벼 유식물을 이용한 C29-Brassinosteroids의 대사

  • Won, So-Yun (Department of Life Science, Chung-Ang University) ;
  • Joo, Se-Hwan (Department of Life Science, Chung-Ang University) ;
  • Kim, Seong-Ki (Department of Life Science, Chung-Ang University)
  • Published : 2007.09.29
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Abstract

It has been recently demonstrated the presence of not only $C_{28}-BRs$ biosysnthesis, but also $C_{27}-$ and $C_{29}-BRs$ biosynthesis in plants, suggesting that BRs biosynthesis are complicatedly connected to produce biologically active BR (s). This prompted us to investigation of metabolism of a $C_{29}-BR$, 28-homoCS in seedlings of rice from which $C_{29}-BRs$ such as 28-homoTE and 28-homoTY have been identified. In vitro enzyme conversion study using a crude enzyme solution prepared from rice seedlings revealed that 28-homoCS is converted into both CS and 26-nor-28-homoCS, but their reversed reaction did not occur. This indicated that 28-homoCS is biosynthetically converted into more biologically active $C_{28}-BR$, CS by C-28 demethylation and biodegraded into 26-nor-28-homoCS by C-26 demethylation. Next, bio-conversion of 28-homoCS to 28-homoBL was examined by the same enzyme solution. No 28-homoBL as a metabolite of 28-homoCS was detected, meaning that biosynthetic reaction for 28-homoCS to 28-homoBL is not contained, and main connection of $C_{28}-BRs$ and $C_{29}-BRs$ biosynthesis is between CS and 28-homoCS in the rice seedling. This study is the first demonstrated that $C_{29}-BRs$ and $C_{28}-BRs$ bionsynthetic pathways are connected, and that $C_{29}-BRs$ biosynthetic pathway is an alternative biosynthetic pathway to produce more biologically active $C_{28}-BR$, CS in plant.

BRs의 생합성 경로는 $C_{28}-BRs$ 생합성 경로 외에 $C_{27}-BRs$ 생합성 경로가 존재함이 확인되었고, 최근 $C_{29}-BRs$의 생합성 경로가 존재함이 보고되어 BRs의 생합성 과정이 복잡하게 연결되어 있을 가능성이 예상되었다. 이에 $C_{29}-BRs$인 28-homoTE와 28-homoTY 등이 동정된 벼의 유식물을 대상으로 하여 $C_{29}-BR$인 25-homoCS의 대사 과정을 조사하였다. 그 결과 in vitro 효소변환 연구를 통해 28-homoCS은 CS와 26-nor-28-homoCS으로 전환됨을 확인 할 수 있었으며, 그 역반응인 CS에서 28-homoCS로 또는 26-nor-28-homoCS에서 28-homoCS로의 전환은 일어나지 않음을 알 수 있었다. 이는 $C_{29}-BRs$인 28-homoCS은 C-28위치의 demethylation에 의해 보다 강한 활성의 $C_{28}-BRs$인 CS로 생합성 되는 과정과 C-26 위치의 demethylation에 의해 26-nor-28-homoCS으로 생분해 되는 과정이 존재함을 최초로 확인하였다. 한편, $C_{28}-BRs$인 CS에서 BL로의 전환과 동일한 반응이 $C_{29}-BRs$에서도 일어나는지 확인하고자 하였으나 벼 유식물에서는 28-homoCS에서 28-homoBL로 전환되지 않음을 확인 할 수 있었다. 이는 $C_{29}-BRs$와 $C_{28}-BRs$의 생합성과정의 연결이 28-homoCS에서 CS를 통하고 있음을 알 수 있었다. 따라서 28-homoCS에서 CS로 전환되는 과정을 통하여 $C_{29}-BRs$ 또한 $C_{28}-BRs$ 와 동일한 과정을 거쳐 활성형의 CS로 전환됨을 확인 할 수 있었으며, BRs의 생합성은 $C_{27}-BRs$과 $C_{28}-BRs$의 생합성과정이 연결된 것처럼 $C_{29}-BRs$ 또한 $C_{28}-BRs$ 생합성 과정과 연결되어 있음을 확인 할 수 있었다. 즉, 활성형 BR인 CS은 $C_{27}-BRs$, $C_{28}-BRs$의 생합성 과정뿐만 아니라 $C_{29}-BRs$의 생합성 과정을 통하여 생성되는 과정이 식물체내에 존재함을 확인 할 수 있었다.

Keywords

References

  1. Abe H (1991) Rice-lamina inclination, endogenous levels in plant tissues and accumulation during pollen development of brassinosteroids. In: Cutler HG, Yokota T, Adam G eds., Brassinosteroids: Chemistry, Bioactivity and Applications. American Chemical Society, Washington, DC, pp. 200-207
  2. Abe H, Nakamura K, Morishita T, Uchiyama M, Takatsuto S, Ikekawa N (1984) Endogenous brassinosteroids of the rice plant: Castasterone and dolichosterone. Agric Biol Chem 48: 11 03-11 04
  3. Abe H, Takatsuto S, Nakayama M, Yokota T (1995) 28-homotyphasterol, a new natural brassinosteroid from rice (Oryza sativa L.) bran. Biosci Biotech Biochem 59: 176-178 https://doi.org/10.1271/bbb.59.176
  4. Bishop GJ, Harrison K, Jones J (1996) The tomato Dwarf gene isolated by heterologous transposon tagging encodes the first member of a new cytochrome P450 family. Plant Cell 8: 959-969 https://doi.org/10.1105/tpc.8.6.959
  5. Bishop GJ, Nomura T, Yokota T, Harrison K, Noguchi T, Fujioka S, Takatsuto S, Jones JD, Kamiya Y (1999) The tomato DWARF enzyme catalyzes C-6 oxidation in brassinosteroid biosynthesis. Proc Natl Acad Sci USA 96: 1761-1766
  6. Bishop GJ, Yokota T (2001) Plants Steroid Hormones, Brassinosteroids: Current Highlights of Molecular Aspects on their Synthesis/Metabolism, Transport, Perception and Response. Plant Cell Physiol 42: 114-120 https://doi.org/10.1093/pcp/pce018
  7. Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72: 248-254 https://doi.org/10.1016/0003-2697(76)90527-3
  8. Fujioka S (1999) Natural occurrence of brassinosteroids in the plant kingdom. In A Sakurai, T Yokota, SD Clouse, eds, Brassinosteroids: Steroidal Plant Hormones. Springer-Verlag, Tokyo, pp. 21-45
  9. Hong Z, Ueguchi-Tanaka M, Shimizu-Sato S, lnukai Y, Fujioka S, Shimada Y, Takatsuto S, Agetsuma M, Yoshida S, Watanabe Y, Uozu S, Kitano H, Ashikari M, Matsuoka M (2002) Loss-of-function of a rice brassinosteroid biosynthetic enzyme, C-6 oxidase, prevents the organized arrangement and polar elongation of cells in the leaves and stem. Plant J 32: 495-508 https://doi.org/10.1046/j.1365-313X.2002.01438.x
  10. Kim TW, Chang SC, Lee JS, Takatsuto S, Yokota T, Kim SK (2004) Novel biosyntheic pathway of castasterone from cholesreol in tomato. Plant Physiol 135: 1231-1242 https://doi.org/10.1104/pp.104.043588
  11. Kim YS, Joo SH, Hwang JY, Park CH, Kim SK (2006). Characterization of $C_{29}$-Brassinosteroids and Their Biosynthetic Precursors in Immature Seeds of Phaseolus vulgaris. Bull Korean Chem Soc 27. 1117-1118 https://doi.org/10.5012/bkcs.2006.27.8.1117
  12. Li J and Chory J (1999). Review article. Brassinosteroid actions in plants. J Exp Bot 50; 275-282 https://doi.org/10.1093/jexbot/50.332.275
  13. Sakurai A (1999) Biosynthesis. In A Sakurai, T Yokota, SD Clouse, eds, Brassinosteroids: Steroidal Plant Hormones. Springer-Verlag, Tokyo, pp. 137-161
  14. Yokota T (1997) The structure, biosynthesis and function of brassinosteroids. Trends Plant Sci 2: 137-143 https://doi.org/10.1016/S1360-1385(97)01017-0
  15. Yokota T (2000) Brassiniosteroids. In BB Buchanan, W Gruissem, RL Jones, eds, Biochemistry and molecular biology of plants. Amer Soc Plant Physiol, Maryland, pp. 901-911
  16. Yokota T, Nomura T, Nakayama M (1997) Identification of brassinosteroids that appear to be derived from campesterol and cholesterol in tomato shoots. Plant Cell Physiol 38: 1291-1294 https://doi.org/10.1093/oxfordjournals.pcp.a029119
  17. Yokota T, Sato T, Takeuchi Y, Nomura T, Uno K, Watanabe T, Takatsuto S (2001) Roots and shoots of tomato produce 6-deoxo-28-norcathasterone, 6-deoxo-28-nortyphasterol and 6-deoxo-28-norcastasterone, possible precursors of 28norcastasterone. Phytochemistry 58: 233-238 https://doi.org/10.1016/S0031-9422(01)00237-0