BACKGROUND

Dehydrin (DHN) proteins, belong to subfamily members of late embryogenesis abundant (LEA) proteins, are widely recognized as key determinants in plant abiotic stress tolerance.

RESULTS

In this study, we identified eleven DHN genes in Zea mays and systematically analyzed their evolutionary relationships, structural features, cis-acting elements, expression patterns, protein interaction relation, and function validation in drought resistance. All ZmDHN proteins contained K-segment, and were classified into three subgroups, i.e., KnS-, SKn-, and YnSKn-type. Promoter analysis results showed abundant stress-responsive cis-elements were identified in ZmDHN promoter regions, especially MBS and ABRE elements. Consistently, the most ZmDHNs were induced by cold, heat, salt, and drought stresses, except ZmDHN7 to ZmDHN11. Protein interaction and transcriptome data analysis suggested that ZmDHN1 might interact with cell division protein, ZmDHN3 interacted with nucleic acid binding protein, ZmDHN4 interacted with alpha/beta-hydrolases, ZmDHN5 interacted with ATP synthase, ZmDHN6 interacted with glycine-rich RNA-binding protein, ZmDHN8 and ZmDHN9 interacted with late embryogenesis abundant protein Lea14-A under drought stress. Functional validation results demonstrated that ZmDHN3 was located in the cytoplasm, and overexpression of ZmDHN3 in maize enhanced drought tolerance, with higher relative water content and lower relative electrolyte leakage compared with wild-type maize plants.

CONCLUSIONS

This study increases our understanding of DHN proteins, demonstrates that ZmDHN3 improves drought tolerance in maize, and provides candidate genes for further molecular breeding to improve maize drought stress tolerance.