Oryzalexin S structure: a new stemarane-type rice plant phytoalexin and its biogenesis.

Tamogani, Shigeru; Mitani, Masahiro; Kodama, Osamu; Akatsuka, Tadami

doi:10.1016/s0040-4020(01)86302-x

Cited by 67 publications

(44 citation statements)

References 9 publications

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“…24) These compounds are transiently generated in response to signal molecules called elicitors, which are usually derived from pathogens, such as the rice blast fungus Magnaporthe oryzae. Phytoalexins have been classified into four structurally distinct types of polycyclic diterpenoids based on the structures of their diterpene hydrocarbon precursors: phytocassanes A to E, oryzalexins A to F, momilactones A and B, and oryzalexin S. [25][26][27][28][29][30][31][32][33] Upon synthesis of these phytoalexins, the common substrate GGPP is converted into diterpene hydrocarbon precursors via two-step sequential cyclization. Toyomasu and our group identified and characterized all six diterpene cyclases involved in phytoalexins biosynthesis.…”

Section: Inductive Biosynthetic Gene Clusters For Diterpene Phytomentioning

confidence: 99%

The Biosynthesis of Isoprenoids and the Mechanisms Regulating It in Plants

Okada

2011

Bioscience, Biotechnology, and Biochemistry

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Section: Inductive Biosynthetic Gene Clusters For Diterpene Phytomentioning

confidence: 99%

The Biosynthesis of Isoprenoids and the Mechanisms Regulating It in Plants

Okada

2011

Bioscience, Biotechnology, and Biochemistry

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“…[3][4][5][6][7][8][9][10] Except for the flavonoid sakuranetin, they are all diterpenoids. The rice diterpenoid phytoalexins are classified into four groups based on their basic carbon frameworks: phytocassanes A-E, 8,9,11) oryzalexins A-F, [4][5][6]12) momilactones A and B, 3,13) and oryzalexin S, 7) the major ones being phytocassanes and momilactones.…”

Section: Introductionmentioning

confidence: 99%

Effects of cytokinin on production of diterpenoid phytoalexins in rice

Okada

Koga³

et al. 2010

J. Pestic. Sci.

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IntroductionHigher plants that are attacked by pathogenic microorganisms respond with a variety of defense reactions, including the production of secondary metabolites called phytoalexins, which serve as plant antibiotics.In rice, 15 compounds have been identified as phytoalexins in suspension-cultured cells treated with a biotic elicitor such as a chitin oligosaccharide or a cerebroside [1][2] and/or in leaves either infected with the blast fungus Magnaporthe oryzae or irradiated with UV light. [3][4][5][6][7][8][9][10] Except for the flavonoid sakuranetin, they are all diterpenoids. The rice diterpenoid phytoalexins are classified into four groups based on their basic carbon frameworks: phytocassanes A-E, 8,9,11) oryzalexins A-F, [4][5][6]12) momilactones A and B, 3,13) and oryzalexin S, 7) the major ones being phytocassanes and momilactones.As shown in Fig. 1, the common precursor geranylgeranyl diphosphate (GGDP) is cyclized to ent-copalyl diphosphate (ent-CDP) and then to ent-cassa-12,15-diene and ent-sandaracopimaradiene, leading to phytocassanes A to E and oryzalexins A to F, respectively. GGDP is also cyclized to syn-CDP and then to 9b H-pimara-7,15-diene and stemar-13-ene, leading to momilactones A and B and oryzalexin S, respectively. By utilizing the information from the rice genome database that recently opened to the public, six diterpene cyclases have been demonstrated to be involved in the conversion of GGDP to the four diterpene hydrocarbon precursors via ent-or syn-CDP. ent-CDP synthase (OsCPS2) and syn-CDP synthase (OsCPS4) catalyze the conversion of GGDP to ent-CDP and syn-CDP (14), and ent-cassa-12,15-diene synthase (OsKSL7), ent-sandaracopimaradien synthase (OsKSL10), 9b H-pimara-7,15-diene synthase (OsKSL4), and stemar-13-ene synthase (OsKSL8) catalyze the conversion of ent-CDP or syn-CDP to the four diterpene hydrocarbons ent-cassa-12,15-diene, entsandaracopimaradiene, 9b H-pimara-7,15-diene, and stemar-13-ene, respectively. [15][16][17] The methylerythritol phosphate (MEP) pathway genes have been shown to be responsible for chitin oligosaccharide elicitor-inducible production of diterpenoid phytoalexins in suspension-cultured rice cells, 18) and microsomal P450s and a dehydrogenase have also been shown to be involved in the downstream oxidation of diterpene hydrocarbons. 19) On the other hand, secondary signaling molecules, including plant hormones, have been indicated to be involved in the defense responses caused by pathogen attacks. For example, salicylic acid, jasmonic acid (JA), and ethylene have been investigated extensively and shown to play crucial roles as sec- Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan (Received November 18, 2009; Accepted May 13, 2010) The production of phytoalexins is a well-documented defense response against pathogen infection in rice. Although jasmonic acid has been suggested to be involved in the production of phytoalexins in both suspensioncultured rice cells and rice leaves, there has been almost no information on other secondary signaling mole...

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“…A large number of phytotoxic substances (allelochemicals) including diterpene and flavanone phytoalexins, which are involved in the defense mechanism of the rice plant have been isolated as phytoalexins such as M A and M B (Figure 1), oryzalexin A-F, phytocassanes A to D and the flavonoid phytoalexin sakuranetin (Cartwright et al 1977, Kodama et al 1992, Kato et al 1993, Tamogani et al 1993, Koga et al 1997, Chung et al 2005. The diterpenoids (M A and M B ) were first isolated by Japanese scientists from rice husks (Kato et al 1973) and indicated by them as potential plant growth inhibitors.…”

Section: Introductionmentioning

confidence: 99%

Comparative efficaciesin vitroof antibacterial, fungicidal, antioxidant, and herbicidal activities of momilatones A and B

Fukuta¹,

Xuan²,

Deba³

et al. 2007

Journal of Plant Interactions

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Momilactones A (M A ) and B (M B ) are phytoalexins derived from rice plant (Oryza sativa) and were considered to be a part of the mechanism of rice self-defense system. The present study was to evaluate the comparative efficacies in vitro of antibacterial, fungicidal, antioxidant, and herbicidal activities of M A and M B . In general, M B shows higher antifungal, antibacterial, and herbicidal action than M A , although its antioxidant property was less than M A . In herbicidal trial, the IC 50 values of M B against germination, shoot and root elongation of barnyardgrass and monochoria were 40.9, 45.5, and 27.5, and 27.1, 17.3, and 0.9 mg, respectively. For M A , these values were 40.3, 35.6, and 55.1, and 43.9, 24.3, and 0.5 mg, respectively. For antifungal activity, momilactone B (IC 50 : 1.2, 123.9, and 53.4 mg) exerted significantly greater inhibition than M A (IC 50 : 78.1, 198.1, and 95.3 mg) against Botrytis cinerea, Fusarium solani, Colletrotrichum gloeosporioides, respectively, except for Fusarium oxysporum that both M A and M B showed no marked difference. In addition, M B exhibited significantly stronger antibacterial activity than M A against Pseudomonus ovalis, Bacillus cereus, and Bacillus pumilus, whereas the inhibitory activity of the two compounds was similar against Escherichia coli. Both M A and M B exerted rather weak antioxidant activity (EC 50 was 783.9 and 790.7 mg, respectively), of which M A showed a slightly stronger antioxidant activity than M B . This study is the first to examine antifungal, antibacterial, and antioxidant activities of two phytoalexins, as well as their comparative efficacies against growth of the noxious weeds barnyardgrass and monochoria.

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Oryzalexin S structure: a new stemarane-type rice plant phytoalexin and its biogenesis.

Cited by 67 publications

References 9 publications

The Biosynthesis of Isoprenoids and the Mechanisms Regulating It in Plants

The Biosynthesis of Isoprenoids and the Mechanisms Regulating It in Plants

Effects of cytokinin on production of diterpenoid phytoalexins in rice

Comparative efficaciesin vitroof antibacterial, fungicidal, antioxidant, and herbicidal activities of momilatones A and B

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