Biosynthetic enzymes gene suppression

Suzuki Y, Toshiya A, Yukie M, Hirofumi T and Masaya K. 2005. Suppression of the expression of genes encoding ethylene biosynthetic enzymes in harvested broccoli with high temperature treatment. Postharv... 

The cytochrome P450 responsible for the oxidation of (S)-N-methylcoclaurine to (S)-3 -hydroxy-N-methylcocluarine has been overexpressed in opium poppy plants, and morphinan alkaloid production in the latex is increased subsequently to 4.5 times the level in wild-type plants (58). Additionally, suppression of this enzyme resulted in a decrease in morphinan alkaloids to 16% of the wild-type level. Notably, analysis of a variety of biosynthetic gene transcript levels in these experiments supports the hypothesis that this P450 enzyme plays a regulatory role in the biosynthesis of benzylisoquinoline alkaloids. Collectively, these studies highlight that the complex metabolic networks found in plants are not redirected easily or predictably in all cases. 

Kempe K, Higashi Y, Frick S, Sabama K, Kutchan TM (2009) RNAi suppression of the mruphine biosynthetic gene salAT and evidence of association of pathway enzymes. Phyto-cheirustry 70 579—589... 

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