Molecular cloning and functional analysis of MbWRKY3 involved in improved drought tolerance in transformed tobacco

摘要

Plant-specific WRKY transcription factors were involved in stress responses and ABA signaling. In the present study, a WRKY gene is isolated from Malus baccata (L.) Borkh and designated as MbWRKY3 . Subcellular localization revealed that MbWRKY3 was localized onto nucleus. The MbWRKY3 expression levels were up-regulated by salinity, drought, and ABA treatments in M.?baccata . When MbWRKY3 was introduced into tobaccos, it improved drought stress tolerance in transgenic plants . Compared to WT, the transgenic tobaccos had the higher levels of relative water content, and proline and chlorophyll contents, decreased levels of electrolyte leakage, MDA, and H 2 O 2 , increased activities of the reactive oxygen species-related enzymes (SOD, CAT, and POD), and greater up-regulations of the corresponding genes ( NtSOD , NtCAT , and NtPOD ), especially when dealt with drought stress. These results suggest that MbWRKY3 gene plays a positive regulatory role in drought stress response.