PubMed · 2026-07-04
Scientists identified the gene behind barley's 'orange lemma' mutation, a long-mysterious color change in husks. The culprit is CAD, an enzyme that helps build lignin; when it's broken, husks turn orange and lignin drops, making the grain and straw easier to digest and convert to biofuel.
The CAD gene on chromosome 6H is the sole cause of the orange lemma phenotype in barley, confirmed across naturally occurring mutants, EMS-induced lines, and CRISPR knockout plants.
CRISPR/Cas9 knockout of CAD in the 'Golden Promise' cultivar reproduced the orange husk color and produced significantly lower lignin content than wild-type plants.
All orange lemma mutants carried nucleotide changes in CAD resulting in amino acid substitutions or premature stop codons, explaining decades of observed phenotypic variation.
