Tailoring poplar lignin without yield penalty by combining a null and haploinsufficient CINNAMOYL-CoA REDUCTASE2 allele

Nat Commun. 2020 Oct 6;11(1):5020. doi: 10.1038/s41467-020-18822-w.

Abstract

Lignin causes lignocellulosic biomass recalcitrance to enzymatic hydrolysis. Engineered low-lignin plants have reduced recalcitrance but often exhibit yield penalties, offsetting their gains in fermentable sugar yield. Here, CRISPR/Cas9-generated CCR2(-/*) line 12 poplars have one knockout CCR2 allele while the other contains a 3-bp deletion, resulting in a 114I115A-to-114T conversion in the corresponding protein. Despite having 10% less lignin, CCR2(-/*) line 12 grows normally. On a plant basis, the saccharification efficiency of CCR2(-/*) line 12 is increased by 25-41%, depending on the pretreatment. Analysis of monoallelic CCR2 knockout lines shows that the reduced lignin amount in CCR2(-/*) line 12 is due to the combination of a null and the specific haploinsufficient CCR2 allele. Analysis of another CCR2(-/*) line shows that depending on the specific CCR2 amino-acid change, lignin amount and growth can be affected to different extents. Our findings open up new possibilities for stably fine-tuning residual gene function in planta.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aldehyde Oxidoreductases / genetics*
  • Aldehyde Oxidoreductases / metabolism
  • Alleles
  • Gene Knockout Techniques
  • Haploinsufficiency
  • Lignin / genetics
  • Lignin / metabolism*
  • Mutation
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plants, Genetically Modified
  • Populus / genetics*
  • Populus / growth & development
  • Populus / metabolism*
  • Xylem / metabolism
  • Xylem / ultrastructure

Substances

  • Plant Proteins
  • Lignin
  • Aldehyde Oxidoreductases
  • cinnamoyl CoA reductase