A pendant awn phenotype linked to the EMBRYONIC FLOWER 1 LIKE (EMF1L) gene in barley

HvEMF1L mutants display pleiotropic defects in spike morphology, especially awn development in barley. The study integrates mutagenesis, genetic mapping and sequencing technologies for trait dissection Awns are apical extensions of the lemma that are prevalent in many wild and cultivated grass species. In cultivated cereals they are relevant, given their influence on grain yield through contributions to photosynthesis, transpiration, carbohydrate accumulation and drought stress mitigation. While several genetic factors controlling barley awn traits have been identified, their complex network and interactions are not fully understood. This study characterizes a "pendant awn" mutant derived from an ethyl methanesulfonate (EMS)-mutagenized population of the two-rowed winter barley cultivar 'Igri' which is marked by shorter, thinner, and less upright awns. Segregation analyses in an F₂ population of 149 individuals indicated a monogenic recessive inheritance of the mutant trait. Molecular genetic mapping identified a 356.8 Mbp region on chromosome 3H associated with the pendant awn mutant trait. Whole-genome re-sequencing of mutant and wild-type individuals led to the discovery of a premature stop codon mutation specific to the pendant awn mutant in the EMBRYONIC FLOWER 1 LIKE (HvEMF1L) gene, predicted to truncate the protein by 62.3%. Pan-genomic and -transcriptomic analyses revealed a high level of sequence conservation of HvEMF1L in global barley germplasm and an inflorescence-specific gene expression profile. The study highlights HvEMF1L as a putative regulator of barley awn development and underscores the scope of combining mutagenesis, genetic mapping, and genome sequencing for trait dissection.