Isolation and characterization of a dehydration responsive element binding factor MsDREBA5 in Malus sieversii Roem.

A dehydration responsive element binding (DREB) protein homologous gene, designated MsDREBA5 (GenBank ID: JQ655768), was isolated from Malus sieversii Roem. Based on similarity with AP2 domains, MsDREBA5 was cladeded into the A-5 subgroup in DREB subfamily in AP2/ERF family. Subcellular localization analyses revealed that MsDREBA5 was subcellularly localized into the nucleus when transiently expressed in onion epidermis cells. The MsDREBA5 protein might show no transcriptional activation ability. The 1624-bp-long promoter contained putative cis-acting elements and transcription factor binding motifs, including elements predicted to respond to abiotic stresses. MsDREBA5 was expressed in almost all the tissues and organs examined under normal conditions. Additionally, expression of MsDREBA5 was induced by cold, drought and exogenously applied abscisic acid, but down-regulated by salt stress. Transgenic Arabidopsis plants overexpressing MsDREBA5 appeared to down-regulate the expression levels of the stress-induced effecter genes under drought stress. Our findings may provide an important basis for further studies of the acclimation and tolerance of M. sieversii to abiotic stresses.

► Malus sieversii (Ledeb.) Roem. is believed to be progenitor of modern cultivated apple and one of the most drought tolerant apple rootstocks in China. ► MsDREBA5 was targeted to the nucleus and showed no transcriptional activation ability. ► Expression of MsDREBA5 was induced by several abiotic stresses. ► Our findings may provide a novel basis for further studies on tolerance of M. sieversii to abiotic stresses.