J Integr Plant Biol ›› 2015, Vol. 57 ›› Issue (4): 341-348.DOI: 10.1111/jipb.12333

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Norway spruce (Picea abies) laccases: Characterization of a laccase in a lignin-forming tissue culture

Sanna Koutaniemi1, Heli A. Malmberg1†, Liisa K. Simola2‡, Teemu H. Teeri1 and Anna Kärkönen1*   

  • 收稿日期:2014-11-05 接受日期:2015-01-14 出版日期:2015-04-01 发布日期:2015-01-27

Norway spruce (Picea abies) laccases: Characterization of a laccase in a lignin-forming tissue culture

Sanna Koutaniemi1, Heli A. Malmberg1†, Liisa K. Simola2‡, Teemu H. Teeri1 and Anna Kärkönen1*   

  1. 1Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
    2Department of Biosciences, University of Helsinki, Helsinki, Finland
  • Received:2014-11-05 Accepted:2015-01-14 Online:2015-04-01 Published:2015-01-27
  • About author:†These authors contributed equally to this work.
    ‡Present address: Ritarikatu 9 B, Helsinki 00170, Finland.
    *Correspondence: E-mail: anna.karkonen@helsinki.fi

摘要： In order to resolve how lignin, an important cell wall component is synthesized in Norway spruce, we have studied laccases with biochemical, molecular biological and bioinformatic means. Laccases are enzymes that participate in the final stages of lignin biosynthesis in many species. Spruce contains numerous laccase genes in the genome.

Abstract:

Secondarily thickened cell walls of water-conducting vessels and tracheids and support-giving sclerenchyma cells contain lignin that makes the cell walls water impermeable and strong. To what extent laccases and peroxidases contribute to lignin biosynthesis in muro is under active evaluation. We performed an in silico study of Norway spruce (Picea abies (L.) Karst.) laccases utilizing available genomic data. As many as 292 laccase encoding sequences (genes, gene fragments, and pseudogenes) were detected in the spruce genome. Out of the 112 genes annotated as laccases, 79 are expressed at some level. We isolated five full-length laccase cDNAs from developing xylem and an extracellular lignin-forming cell culture of spruce. In addition, we purified and biochemically characterized one culture medium laccase from the lignin-forming cell culture. This laccase has an acidic pH optimum (pH 3.8–4.2) for coniferyl alcohol oxidation. It has a high affinity to coniferyl alcohol with an apparent Km value of 3.5 μM; however, the laccase has a lower catalytic efficiency (Vmax/Km) for coniferyl alcohol oxidation compared with some purified culture medium peroxidases. The properties are discussed in the context of the information already known about laccases/coniferyl alcohol oxidases of coniferous plants.

 

Koutaniemi S, Malmberg HA, Simola LK, Teeri TH, Kärkönen A (2015) Norway spruce (Picea abies) laccases: Characterization of a laccase in a lignin-forming tissue culture. J Integr Plant Biol 57: 341–348 doi: 10.1111/jipb.12333

Key words: Coniferyl alcohol oxidase, developing xylem, laccase, lignin biosynthesis, Norway spruce, Picea abies, tissue culture

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