EC 4.2.3.35     
Accepted name: syn-pimara-7,15-diene synthase
Reaction: 9α-copalyl diphosphate = 9β-pimara-7,15-diene + diphosphate
Glossary: syn-copalyl diphosphate = 9α-copalyl diphosphate
syn-pimara-7,15-diene = 9β-pimara-7,15-diene
Other name(s): 9β-pimara-7,15-diene synthase; OsDTS2; OsKS4
Systematic name: 9α-copalyl-diphosphate diphosphate-lyase (9β-pimara-7,15-diene-forming)
Comments: This enzyme is a class I terpene synthase [1]. 9β-Pimara-7,15-diene is a precursor of momilactones A and B, rice diterpenoid phytoalexins that are produced in response to attack (by a pathogen, elicitor or UV irradiation) and are involved in the defense mechanism of the plant. Momilactone B can also act as an allochemical, being constitutively produced in the root of the plant and secreted to the rhizosphere where it suppresses the growth of neighbouring plants and soil microorganisms [1].
References:
1.  Wilderman, P.R., Xu, M., Jin, Y., Coates, R.M. and Peters, R.J. Identification of syn-pimara-7,15-diene synthase reveals functional clustering of terpene synthases involved in rice phytoalexin/allelochemical biosynthesis. Plant Physiol. 135 (2004) 2098–2105. [PMID: 15299118]
2.  Otomo, K., Kanno, Y., Motegi, A., Kenmoku, H., Yamane, H., Mitsuhashi, W., Oikawa, H., Toshima, H., Itoh, H., Matsuoka, M., Sassa, T. and Toyomasu, T. Diterpene cyclases responsible for the biosynthesis of phytoalexins, momilactones A, B, and oryzalexins A-F in rice. Biosci. Biotechnol. Biochem. 68 (2004) 2001–2006. [PMID: 15388982]
[EC 4.2.3.35 created 2008]
 
 


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