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

Article first published online: 25 FEB 2013
DOI: 10.1111/nph.12179
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
Additional Information
How to Cite
Vanholme, B., Cesarino, I., Goeminne, G., Kim, H., Marroni, F., Van Acker, R., Vanholme, R., Morreel, K., Ivens, B., Pinosio, S., Morgante, M., Ralph, J., Bastien, C. and Boerjan, W. (2013), Breeding with rare defective alleles (BRDA): a natural Populus nigra HCT mutant with modified lignin as a case study. New Phytologist, 198: 765–776. doi: 10.1111/nph.12179
Publication History
- Issue published online: 12 APR 2013
- Article first published online: 25 FEB 2013
- Manuscript Accepted: 2 JAN 2013
- Manuscript Received: 15 NOV 2012
Funded by
- European Commission within the Seventh Framework Programme for Research. Grant Number: FP7
- ENERGYPOPLAR. Grant Number: FP7-211917
- NOVELTREE. Grant Number: 211868
- Bijzonder Onderzoeksfonds-Zware Apparatuur of the Ghent University. Grant Number: 174PZA05
- Hercules Foundation. Grant Number: AUGE/014
- U.S. Department of Energy's Great Lakes Bioenergy Research Center. Grant Number: BER DE–FC02–07ER64494
- Multidisciplinary Research Partnership Ghent Bio-Economy
Keywords:
- Breeding with rare defective alleles (BRDA);
- EcoTILLING;
- lignin;
- natural population;
- p-hydroxyphenyl;
- poplar;
- shikimate
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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