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Lignin studies of transgenic Norway spruce

Wadenbäck, Johan (2006). Lignin studies of transgenic Norway spruce. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2006:64
ISBN 91-576-7113-3
[Doctoral thesis]

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An attractive objective in tree breeding is to reduce the content of lignin, or increase its extractability, to favor delignification during pulping. This study investigates the potential for lignin alterations in Norway spruce (Picea abies [L.] Karst) using genetic engineering. Young plants from seven lines transformed with an antisense construct of a gene encoding cinnamoyl CoA reductase (CCR), an important enzyme of lignin biosynthesis, have been compared with control plants. Transgene copy-number varied from 1-8 and the transcript abundance of CCR was reduced by up to 50%. The transcript abundances of lignin biosynthetic genes were positively correlated, especially for those at the end of the pathway. The lignin content and the non-condensed p-hydroxyphenyl (H) lignin fraction was reduced 5% and 23%, respectively. No increase in delignification from pulps from the most down-regulated lines was observed, suggesting an increased proportion of condensed bonds in the lignin. Lignin characters were compared in one-year-old plants and nine-year-old trees of full-sib families. The lignin did not vary within or among the families at the same age. However, the lignin content and the non-condensed H-lignin fraction were increased 15% and 75%, respectively, in the trees, indicating compression wood. In addition, the concentration of C9-units and the ratio of erythro- and threo stereoisomers varied among the families with age. Possibilities for early selection among asCCR embryogenic cultures were evaluated by microarray analysis. Down-regulation of CCR does not affect the transcript abundance of genes regulating lignin biosynthesis. However, several genes in pathways associated with lignin biosynthesis were affected. Functional assignment by Gene Ontology terms showed that transformation with asCCR especially affects processes in the cell wall, chromatin, DNA and the chromosome. The desire to monitor transcript abundance with microarray starting from small amounts of mRNA has led to several protocols for amplification. We compared two amplification methods, PCR and T7-transcription. Amplification by T7-transcription better reflects the variation of the unamplified transcriptome, and gives transcripts with a greater range of lengths, greater estimated mean length, and greater variation of expression levels, but lower average GC content, than those from PCR.

Authors/Creators:Wadenbäck, Johan
Title:Lignin studies of transgenic Norway spruce
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2006
Number of Pages:48
ALLI. Wadenbäck, J., Clapham, D., Gellerstedt, G., von Arnold, S. 2004. Variation in content and composition of lignin in young wood of Norway spruce. Holzforschung, 58, 107–115. II. Wadenbäck, J., von Arnold, S., Egertsdotter, U., Walter, M., Grima-Pettenati, J., Gellerstedt, G., Gullion, T., Clapham, D. Lignin biosynthesis in transgenic Norway spruce harboring antisense constructs of cinnamoyl CoA reductase (CCR). (Submitted). III. Wadenbäck, U., Egertsdotter, U., von Arnold, S., Göransson, H., Ameur A., Clapham, D. Down-regulation of the gene encoding cinnamoyl CoA reductase affects several genes associated with cell wall function in embryogenic cultures of Norway spruce. (Manuscript). IV. Wadenbäck, J., Clapham, D.H., Craig, D., Sederoff, R., Peter, G.F., von Arnold, S., Egertsdotter, U., 2005. Comparison of standard exponential and linear techniques to amplify small cDNA samples for microarrays. BMC Genomics, 6:61 doi:10.1186/1471-2164-6-61.
Place of Publication:Uppsala
ISBN for printed version:91-576-7113-3
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:picea abies, transgenic plants, lignins, wood, genetic engineering, gene expression, pcr
Keywords:acetyl bromide method, Cinnamoyl CoA reductase (CCR), Gene Ontology (GO), lignin, microarray, Picea abies [L.] Karst, real-time PCR, thioacidolysis, transgenic, wood
Permanent URL:
ID Code:1237
Department:(NL, NJ) > Dept. of Plant Biology and Forest Genetics (until 131231)
Deposited By: Johan Wadenbäck
Deposited On:18 Oct 2006 00:00
Metadata Last Modified:02 Dec 2014 10:10

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