Momilactone biosynthesis (WP2209)

Oryza sativa

Phytoalexins Momilactone A and B accumulate in rice husks. Both compounds act in multiple ways such as (1) growth inhibitors involved in seed dormancy, (2) play an important role in the rice plant defense system against pathogens and insects and (3) contribute to allelopathy where they inhibit the growth of weeds. They are also known to be induced by the jasmonic acid plant growth hormone.


Pankaj Jaiswal , Daniela Digles , Egon Willighagen , Finterly Hu , and Eric Weitz


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Oryza sativa



Pathway Ontology

diterpenoid biosynthetic pathway momilactone biosynthetic pathway


Label Type Compact URI Comment
Momilactone B Metabolite pubchem.compound:3084979
Momilactone A Metabolite chebi:49191
Geranylgeranyl Diphosphate Metabolite chebi:57533
LOC_Os04g54474 (OsTGAP1) GeneProduct :LOC_Os04g54474
LOC_Os04g09900.1 GeneProduct :LOC_Os04g09900.1 ent-kaurene synthase, chloroplast precursor, putative, expressed//diterpene phytoalexin precursor biosynthetic process pathway//metabolic process//gibberellin metabolic process//ent-copalyl diphosphate synthase
LOC_Os04g09920 GeneProduct :LOC_Os04g09920 CYP99A3, cytochrome P450 monooxygenase
LOC_Os04g10060.1 GeneProduct :LOC_Os04g10060.1 ent-kaurene synthase, chloroplast precursor, putative, expressed//metabolic process//diterpene phytoalexin metabolic process//syn-pimara-7,15-diene synthase activity//ent-kaurene synthase
LOC_Os04g10160 GeneProduct :LOC_Os04g10160 cytochrome P450, putative, expressed
LOC_OS04G10010.1 GeneProduct :LOC_OS04G10010.1 sex determination protein tasselseed-2, putative, expressed//diterpene phytoalexin precursor biosynthetic process pathway//metabolic process//oxidoreductase activity


  1. Biosynthesis of rice phytoalexins: identification of putative diterpene hydrocarbon precursors. Wickham KA, West CA. Arch Biochem Biophys. 1992 Mar;293(2):320–32. PubMed Europe PMC Scholia
  2. Biosynthesis of cyclic diterpene hydrocarbons in rice cell suspensions: conversion of 9,10-syn-labda-8(17),13-dienyl diphosphate to 9beta-pimara-7,15-diene and stemar-13-ene. Mohan RS, Yee NK, Coates RM, Ren YY, Stamenkovic P, Mendez I, et al. Arch Biochem Biophys. 1996 Jun 1;330(1):33–47. PubMed Europe PMC Scholia
  3. Biosynthesis of rice phytoalexin: enzymatic conversion of 3beta-hydroxy-9beta-pimara-7,15-dien-19,6beta-olide to momilactone A. Atawong A, Hasegawa M, Kodama O. Biosci Biotechnol Biochem. 2002 Mar;66(3):566–70. PubMed Europe PMC Scholia
  4. Identification of syn-pimara-7,15-diene synthase reveals functional clustering of terpene synthases involved in rice phytoalexin/allelochemical biosynthesis. Wilderman PR, Xu M, Jin Y, Coates RM, Peters RJ. Plant Physiol. 2004 Aug;135(4):2098–105. PubMed Europe PMC Scholia
  5. Diterpene cyclases responsible for the biosynthesis of phytoalexins, momilactones A, B, and oryzalexins A-F in rice. Otomo K, Kanno Y, Motegi A, Kenmoku H, Yamane H, Mitsuhashi W, et al. Biosci Biotechnol Biochem. 2004 Sep;68(9):2001–6. PubMed Europe PMC Scholia
  6. Characterization of a rice gene family encoding type-A diterpene cyclases. Kanno Y, Otomo K, Kenmoku H, Mitsuhashi W, Yamane H, Oikawa H, et al. Biosci Biotechnol Biochem. 2006 Jul;70(7):1702–10. PubMed Europe PMC Scholia
  7. Cytotoxic and antitumor activity of momilactone B from rice hulls. Kim SJ, Park HR, Park E, Lee SC. J Agric Food Chem. 2007 Mar 7;55(5):1702–6. PubMed Europe PMC Scholia
  8. Identification of a biosynthetic gene cluster in rice for momilactones. Shimura K, Okada A, Okada K, Jikumaru Y, Ko KW, Toyomasu T, et al. J Biol Chem. 2007 Nov 23;282(47):34013–8. PubMed Europe PMC Scholia
  9. Secretion of momilactone A from rice roots to the rhizosphere. Kato-Noguchi H, Ino T, Ota K. J Plant Physiol. 2008 May 5;165(7):691–6. PubMed Europe PMC Scholia
  10. Diterpene phytoalexins are biosynthesized in and exuded from the roots of rice seedlings. Toyomasu T, Kagahara T, Okada K, Koga J, Hasegawa M, Mitsuhashi W, et al. Biosci Biotechnol Biochem. 2008 Feb;72(2):562–7. PubMed Europe PMC Scholia
  11. Momilactone B, an allelochemical of rice hulls, induces apoptosis on human lymphoma cells (Jurkat) in a micromolar concentration. Lee SC, Chung IM, Jin YJ, Song YS, Seo SY, Park BS, et al. Nutr Cancer. 2008;60(4):542–51. PubMed Europe PMC Scholia
  12. Silicon enhances the accumulation of diterpenoid phytoalexins in rice: a potential mechanism for blast resistance. Rodrigues FA, McNally DJ, Datnoff LE, Jones JB, Labbé C, Benhamou N, et al. Phytopathology. 2004 Feb;94(2):177–83. PubMed Europe PMC Scholia
  13. OsTGAP1, a bZIP transcription factor, coordinately regulates the inductive production of diterpenoid phytoalexins in rice. Okada A, Okada K, Miyamoto K, Koga J, Shibuya N, Nojiri H, et al. J Biol Chem. 2009 Sep 25;284(39):26510–8. PubMed Europe PMC Scholia
  14. Contribution of momilactone A and B to rice allelopathy. Kato-Noguchi H, Hasegawa M, Ino T, Ota K, Kujime H. J Plant Physiol. 2010 Jul 1;167(10):787–91. PubMed Europe PMC Scholia
  15. Phytoalexin accumulation in the interaction between rice and the blast fungus. Hasegawa M, Mitsuhara I, Seo S, Imai T, Koga J, Okada K, et al. Mol Plant Microbe Interact. 2010 Aug;23(8):1000–11. PubMed Europe PMC Scholia
  16. CYP99A3: functional identification of a diterpene oxidase from the momilactone biosynthetic gene cluster in rice. Wang Q, Hillwig ML, Peters RJ. Plant J. 2011 Jan;65(1):87–95. PubMed Europe PMC Scholia
  17. Convergent or parallel molecular evolution of momilactone A and B: potent allelochemicals, momilactones have been found only in rice and the moss Hypnum plumaeforme. Kato-Noguchi H. J Plant Physiol. 2011 Sep 1;168(13):1511–6. PubMed Europe PMC Scholia
  18. The chemical cross talk between rice and barnyardgrass. Kato-Noguchi H. Plant Signal Behav. 2011 Aug;6(8):1207–9. PubMed Europe PMC Scholia
  19. Momilactione B inhibits protein kinase A signaling and reduces tyrosinase-related proteins 1 and 2 expression in melanocytes. Lee JH, Cho B, Jun H jin, Seo WD, Kim DW, Cho KJ, et al. Biotechnol Lett. 2012 May;34(5):805–12. PubMed Europe PMC Scholia
  20. Identification of a degradation intermediate of the momilactone A rice phytoalexin by the rice blast fungus. Imai T, Ohashi Y, Mitsuhara I, Seo S, Toshima H, Hasegawa M. Biosci Biotechnol Biochem. 2012;76(2):414–6. PubMed Europe PMC Scholia