Transgenic sugar beets as industrial plants.
Kuhn, E.;
Zuckerindustrie Year: 1998 Vol: 123 Issue: 1 Pages: 28-34 Ref: 47 ref.
1998
บทคัดย่อ
Development of new industrial plants is one of the main purposes of modern biotechnology. Whereas transgenic oilseed crops are now exploited agroindustrially, modification of plant carbohydrate metabolism is still limited. Despite being one of the world's most important crops - with its high potential for sugar and sugar derivatives as food ingredients and precursors of economically valuable substances - sugarbeet has become amenable to metabolic engineering only slowly. The most serious problems have been caused by inefficient and poorly reproducible regeneration protocols and an almost complete lack of cloned genes known to be expressed specifically in the storage root. The current state of transformation technology suggests that many metabolic alterations of sugarbeet root metabolism can be introduced into the plant, if a cloned gene providing the enzyme function needed is available to catalyse the required modification step. Examples of this category are (1) elimination of undesired constitu
ents, e.g. raffinose, invert sugar and dextran, (2) direct synthesis of carotenoids and/or simple sugar derivatives such as ketosugars, and (3) production of ethanol and other microbial fermentation products by postharvest induction of the necessary enzymes. Among the more distant breeding objectives are the synthesis of better pectins and lignin-free cellulose in sufficient amounts and quality to allow technical applications. This will be feasible only when most or all of the genes involved in the biosynthesis of these biopolymers become known. Transformation and regeneration of sugarbeet has now been improved significantly, and effective molecular methods are available for isolation of developmentally regulated genes. Hence molecular breeding of a first generation of metabolically engineered sugarbeet cultivars should take no longer and be no more difficult than in other transgenic crops (e.g. oilseed rape) that are now used commercially.