• barley
• laccase
• laccasi
• orzo
• sommersione
• submergence

Environmental stresses have a strong impact on crop productivity. Barley is one of the most important cereal crops, widely used for animal feeding, beer production and human diet. It is particularly susceptible to waterlogging and unable to germinate under a prolonged period of submergence. However, some barley accessions can germinate after a short period of submergence followed by a period of recovery in air. A genome-wide association study (GWAS) using high density exome markers was previously performed on a large panel of barley wild, landraces and cultivar accessions, selected in a broad range of different environments. Among the loci identified, a laccase was suggested to be a candidate gene involved in barley germination in recovery after short a period of submergence.
In this study, we selected subgroups of varieties that are tolerant and sensitive to this stress, and we performed experiments to have a better comprehension of laccase function in determining differences in germination. Our results demonstrated that, while the CDS of sensitive and tolerant accessions is similar, promoter regions show a deletion only in sensitive accessions. This promoter region on tolerant varieties is enriched in cis-regulatory elements that are mainly implicated in drought response and ABA-dependent regulation. In parallel, laccase gene expression is higher in sensitive accessions during the last phase of seed development. This is likely due to a lower permeability and capacity to absorb O2 in sensitive accessions.
This work provides new insights on laccase role in germination under submergence followed by post-submergence and lays the basis for further studies aimed at determining laccase function and its expression under different environmental conditions.
Our findings will help to implement barley genetic improvement thereby increasing the capacity of seeds to germinate after a period of submergence stress.