Deciphering barley's stress response: metabolomic strategies and phenotypic implications under multiple abiotic...

Plants are mainly influenced by abiotic stresses acting in combination rather than a single stress acting alone. In the present study leaf metabolomic profiles as well as changes in phenome and yield of four barley (Hordeum vulgare L.) genotypes of different origin under single and combined abiotic stresses were investigated.

The aim of the study was to understand the response of barley to single and combined abiotic stresses and to identify metabolic pathways associated with yield components under stress conditions.

We found that Syrian genotype can be a donor of early resistance caused by rapid increase of amino acids (e.g. proline) under stress, constituting a valuable genetic source in barley breeding. We demonstrated that impact of combined stresses was generally based on the unique response in terms of the metabolomic alterations. However, there were also metabolites that increased their content regardless of the genotype. Methionine sulfoxide has accumulated under long-term drought, salinity and their combination; on the other hand, accumulation of other metabolites such as leucrose increased in drought, but not under its combination with salinity.

Accumulation of most of analysed metabolites significantly depended on the genotype, type of stress as well as their interaction. We indicate that several of identified metabolites might serve as a stress biomarkers (e.g. aspartic acid). We observed that greater phenotypic changes are most visible under the influence of combined stresses being mostly synergistic/additive when compared to single ones as well as considerable relationship between accumulation of specific metabolites and some phenotypic traits.