Isolation and characterization of MbWRKY1, a WRKY transcription factor gene from Malus baccata (L.) Borkh involved in drought tolerance

WRKY transcription factors are involved in stress responses in plants. However, their roles in abiotic stresses are still not well known in Malus plants. In the present study, a WRKY gene was isolated from Malus baccata (L.) Borkh and designated as MbWRKY1. Subcellular localization revealed that MbWRKY1 was localized in nucleus. The expression levels of MbWRKY1 were up-regulated by dehydration, salinity, and ABA treatments in M. baccata seedlings. When MbWRKY1 was introduced into tobacco, it improved drought stress tolerance in transgenic plants. When dealt with drought treatment, the transgenic plants had the higher contents of chlorophyll, proline, relative water content, AsA and GSH than WT. Compared to WT plants, the over-expression of MbWRKY1 in transgenic tobacco also led to decreased levels of H2O2, MDA, and elecrolyte leakage when dealt with drought stress. There were increased activities of POD, CAT, SOD and APX in transgenic tobaccos, especially when dealt with drought treatment. Moreover, the M...