Peel, Gregory , Dixon, R. A. , Pang, Yongzhen .
Transcription factors for metabolic engineering of health- and environmentally-beneficial proanthocyanidins in legumes.
Pasture bloat is a potentially lethal condition for ruminant animals that arises when excessive methane is produced as a result of in-rumen fermentation of protein-rich forages such as alfalfa. Proanthocyanidins, a class of flavonoid-derived polymers, reduce pasture boat and improve nitrogen nutrition for ruminant animals when present in forage, but are absent from the leaves of alfalfa, the world’s major forage legume. For introducing PAs into tissues in which they do not naturally occur, it is necessary to express the anthocyanin pathway from which the flavan-3-ol precursors of PAs are derived. A new class of MYB transcription factors, encoded by the LAP (legume anthocyanin production) genes, was identified from the genome of the model legume Medicago truncatula. When expressed in transgenic alfalfa, M. truncatula or clover, LAP1 induced massive accumulation of anthocyanin pigments comprised of multiple glycosidic conjugates of cyanidin. Over 100 genes were up-regulated in M. truncatula leaves in response to constitutive expression of LAP1, most of which were involved in anthocyanin biosynthesis. By co-expressing LAP1 with anthocyanidin reductase, it was possible to produce alfalfa foliage containing levels of oligomeric proanthocyanidins previously shown to be sufficient for pasture bloat prevention.
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1 - Samuel Roberts Noble Foundation, Plant Biology, 2510 Sam Noble Pky, Ardmore, OK, 73401, USA
2 - Samuel Roberts Noble Foundation, Plant Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM