Bottlenecks for metabolic engineering of isoflavone glycoconjugates in Arabidopsis.
نویسندگان
چکیده
In view of their perceived chemopreventive activities against hormone-dependent cancers, cardiovascular disease, and postmenopausal ailments, there is considerable interest in engineering plants to contain isoflavone phytoestrogens. However, attempts to date have only resulted in low levels of isoflavone accumulation in non-legumes. Introducing soybean isoflavone synthase (IFS) into Arabidopsis thaliana leads to accumulation of low levels of genistein glycosides. Leaves of wild-type A. thaliana contain high levels of similar conjugates of the flavonols quercetin and kaempferol, which could be increased by threefold on introduction of an alfalfa chalcone isomerase transgene. Levels of genistein were not increased by expressing both IFS and alfalfa chalcone isomerase, but levels of flavonol conjugates were reduced to a greater extent than could be accounted for by flux into isoflavone. Introduction of IFS into the tt6/tt3 double mutant blocked in flavonol, and anthocyanin synthesis resulted in high levels of genistein. The bottleneck for constitutive isoflavone production in Arabidopsis is, therefore, competition for flavanone between IFS and endogenous flavonol synthesis, and the flavonol pathway is reciprocally but disproportionately affected by IFS.
منابع مشابه
Production of the isoflavones genistein and daidzein in non-legume dicot and monocot tissues.
Metabolic engineering for production of isoflavones in non-legume plants may provide the health benefits of these phytoestrogens from consumption of more widely used grains. In legumes, isoflavones function in both the symbiotic relationship with rhizobial bacteria and the plant defense response. Expression of a soybean isoflavone synthase (IFS) gene in Arabidopsis plants was previously shown t...
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ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 99 22 شماره
صفحات -
تاریخ انتشار 2002