A gene-editing/complementation strategy for tissue-specific lignin reduction while preserving biomass yield

Area of Science:

• Plant Biotechnology
• Biomass Deconstruction
• Gene Editing

Background:

• Lignocellulosic biomass recalcitrance is a key challenge for biofuel and chemical production.
• Genetic modification to reduce lignin often leads to growth penalties.
• A novel CRISPR-Cas9 gene editing strategy was developed to address this.

Purpose of the Study:

• To develop a method for reducing lignin content in plants without compromising biomass yield.
• To enhance the efficiency of lignocellulosic biomass deconstruction.
• To overcome growth penalties associated with reduced lignin.

Main Methods:

• Utilized a single DNA construct for CRISPR-Cas9 gene editing.
• Knocked out endogenous lignin biosynthesis genes while expressing a modified, Cas9-resistant complementary gene.
• Employed tissue-specific promoters for precise gene expression.

Main Results:

• Generated Arabidopsis plants with reduced lignin content and wild-type biomass yield.
• Achieved up to a fourfold enhancement in cell wall sugar yield per plant.
• Observed stable phenotypes across multiple generations in homozygous and heterozygous lines.

Conclusions:

• The method enables rapid generation of reduced lignin trees and crops via single transformation events.
• This strategy offers a general approach for optimizing loss-of-function traits with associated growth penalties.
• Applicable to various plant species with feasible transformation and available tissue-specific promoters.