Breeding with rare defective alleles (BRDA): a natural Populus nigra HCT mutant with modified lignin as a case study

Authors

  • Bartel Vanholme,

    1. Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Gent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • Igor Cesarino,

    1. Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Gent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • Geert Goeminne,

    1. Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Gent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • Hoon Kim,

    1. Department of Biochemistry, and the DOE Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI, USA
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  • Fabio Marroni,

    1. Istituto di Genomica Applicata, Udine, Italy
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  • Rebecca Van Acker,

    1. Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Gent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • Ruben Vanholme,

    1. Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Gent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • Kris Morreel,

    1. Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Gent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • Bart Ivens,

    1. Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Gent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
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  • Sara Pinosio,

    1. Istituto di Genomica Applicata, Udine, Italy
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  • Michele Morgante,

    1. Istituto di Genomica Applicata, Udine, Italy
    2. Dipartimento di Scienze Agrarie e Ambientali, Università di Udine, Udine, Italy
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  • John Ralph,

    1. Department of Biochemistry, and the DOE Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI, USA
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  • Catherine Bastien,

    1. INRA – Unité Amélioration, Génétique et Physiologie forestières, Olivet, France
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  • Wout Boerjan

    Corresponding author
    1. Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
    • Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Gent, Belgium
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Author for correspondence:

Wout Boerjan

Tel: +32 (0)9 33 13 881

Email: wout.boerjan@psb.vib-ugent.be

Summary

  • Next-generation (NG) sequencing in a natural population of Populus nigra revealed a mutant with a premature stop codon in the gene encoding hydroxycinnamoyl-CoA : shikimate hydroxycinnamoyl transferase1 (HCT1), an essential enzyme in lignin biosynthesis.
  • The lignin composition of P. nigra trees homozygous for the defective allele was compared with that of heterozygous trees and trees without the defective allele. The lignin was characterized by phenolic profiling, lignin oligomer sequencing, thioacidolysis and NMR. In addition, HCT1 was heterologously expressed for activity assays and crosses were made to introduce the mutation in different genetic backgrounds.
  • HCT1 converts p-coumaroyl-CoA into p-coumaroyl shikimate. The mutant allele, PnHCT1-Δ73, encodes a truncated protein, and trees homozygous for this recessive allele have a modified lignin composition characterized by a 17-fold increase in p-hydroxyphenyl units.
  • Using the lignin pathway as proof of concept, we illustrated that the capture of rare defective alleles is a straightforward approach to initiate reverse genetics and accelerate tree breeding. The proposed breeding strategy, called ‘breeding with rare defective alleles’ (BRDA), should be widely applicable, independent of the target gene or the species.

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