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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #123837
Title: TUNING LIGNIN STRUCTURE THROUGH GENETICALLY SILENCING, RESTORING OR INCREASING CAFFEIC ACID 0-METHYLTRANSFERASE ACTIVITY:EVALUATION WITH POPLAR AND ARABIDOPSIS THALIANA MODELS

Author
item JOUANIN, LISE - INRA-VERSAILLES,FRANCE
item GOUJON, THOMAS - INRA-VERSAILLES,FRANCE
item SIBOUT, RICHARD - INRA-VERSAILLES,FRANCE
item POLLET, BRIGITTE - INRA-GRIGNON,FRANCE
item MILA, ISABELLE - INRA-GRIGNON,FRANCE
item Ralph, John
item PETIT-CONIL, MICHEL - CTP,GRENOBLE,FRANCE
item LAPIERRE, CATHERINE - INRA-GRIGNON,FRANCE

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 6/11/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Caffeic acid O-methyltransferase (COMT) is involved in the biosynthesis of lignin syringyl units (S). In order to delineate the impact of COMT activity on lignin structure, transgenic poplars with a COMT activity level close to zero were obtained and their lignin profile was compared to that of the control line. Dramatic lignin alterations were evidenced, including an almost complete lack of S units, the incorporation of 5-hydroxyguaiacyl units into novel benzodioxane lignin structures and an enrichment in carbon-carbon interunit linkages. In spite of a 20% lower lignin content relative to the control, these transgenic poplars displayed markedly lower kraft pulping performances, which emphasizes the importance of lignin structure on kraft efficiency.A COMT null mutant line of Aradidopsis thaliana was identified in the T-DNA insertion library. This DLM6 mutant line displayed the same lignin alteration as the COMT-deficient poplar line. In order to restore both normal COMT activity level and lignin profile, the poplar COMT cDNA was introduced into this Arabidopsis mutant. In addition, it was introduced in Arabidopsis wild-type plants in an attempt to overexpress COMT activity and to examine the corresponding lignin structural alteration. Our results further demonstrate the applicability of the A. thaliana model plant not only to study the lignin biosynthesis pathway, but also to evaluate the possibility of genetically modulating the proportion of S units in plants for improved kraft pulping performance.