CYANOGENESIS IN CASSAVA (MANIHOT-ESCULENTA CRANTZ)

Cassava is the most agronomically important of the cyanogenic crops, Linamarin, the predominant cyanogenic glycoside in cassava, can accumulate to concentrations as high as 500 mg kg(-1) fresh weight in roots and to higher levels in leaves, Recently, the pathway of linamarin synthesis and the cellular site of linamarin storage have been determined, In addition, the cyanogenic enzymes, linamarase and hydroxynitrile lyase, have been characterized and their genes cloned. These results, as well as studies on the organ- and tissue-specific localization of linamarase and hydroxynitrile lyase, allow us to propose models for the regulation of cyanogenesis in cassava, There remain, however, many unanswered questions regarding the tissue-specific synthesis, transport, and accumulation of cyanogenic glycosides. The resolution of these questions will facilitate the development of food processing, biochemical and transgenic plant approaches to reducing the cyanogen content of cassava foods.