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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Cotton Structure and Quality Research » Research » Publications at this Location » Publication #184104
Title: FUNCTIONAL ANALYSIS OF A PUTATIVE RYEGRASS LEUCOANTHOCYANIDIN REDUCTASE

Author
item WHITAKER, D - VIALACTIA, AUCKLAND NZ
item Triplett, Barbara
item RINTELMANN, A - VIALACTIA, AUCKLAND NZ
item CARTER, C - VIALACTIA, AUCKLAND NZ
item BRYANT, C - VIALACTIA, AUCKLAND NZ
item PUTHIGAE, S - VIALACTIA, AUCKLAND NZ
item PHILLIPS, J - VIALACTIA, AUCKLAND NZ
item SMITH-ESPINOZA, C - VIALACTIA, AUCKLAND NZ
item ELBOROUGH, K - VIALACTIA, AUCKLAND NZ

Submitted to: Plant Biology
Publication Type: Abstract Only
Publication Acceptance Date: 11/10/2004
Publication Date: 1/4/2005
Citation: Whittaker, D. Triplett B.A., Rintelmann A., Carter C., Bryant C., Puthigae S., Phillips, J., Smith-Espinoza, C., Elborough, K. 2005. Functional analysis of a putative ryegrass leucoanthocyanidin reductase. Plant Biology 2005, Seattle, WA, abstract 607, http://abstracts.aspb.org/pb2005/public/P57/7368.html

Interpretive Summary:

Technical Abstract: Proanthocyanidins, also known as condensed tannins, are polymeric flavonoids that occur widely in plants and interact strongly with proteins. The presence of condensed tannins in the leaves of forage plants can protect ruminant animals against pasture bloat and improve nitrogen nutrition. However certain forage crops, including perennial ryegrass (Lolium perenne L.) and alfalfa (Medicago sativa L.) contain very low levels of tannins. Manipulation of flavonoid metabolism is therefore of great interest to the pastoral industries. Leucoanthocyanidin reductase (LAR) catalyses the conversion of 3,4-cis-leucocyanidin to catechin, which is thought to act as a monomeric ‘starter unit’ for tannin condensation. We cloned and sequenced a putative leucoanthocyanidin reductase (LAR) cDNA from the fibers of a high-proanthocyanidin line of cotton (Gossypium hirsutum L.). A putative ryegrass orthologue was identified in our Genethresher® genomic sequence database, based on similarity to the cotton gene and the publicly available Desmodium uncinatum LAR gene. Using an Agrobacterium-based protocol, ryegrass was transformed with a construct comprising the full-length ryegrass gene under the control of a CAMV 35S promoter. Elevated levels of a low molecular weight flavonoid compound in the leaves of primary transformants indicated increased LAR activity. Overall proanthocyanidin levels remained low, consistent with a low rate of flux through the proanthocyanidin branch of the flavonoid pathway, and limiting levels of the leucocyanidin substrate.