Abstract
ABSTRACTPlant-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 H2O2, 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.
Highlights
As sessile organisms, plants are frequently exposed to variable environmental stresses, such as drought, salt, heat, chilling, pathogen attack, and nutrient deprivation, which adversely affect plant growth, development, and productivity (Gong & Liu 2013)
Isolation of MbWRKY3 gene from M. baccata Sequence analysis showed that the MbWRKY3 cDNA has a complete ORF of 1059 bp, the predicted MbWRKY3 comprises
Comparing the amino acid sequences of MbWRKY3 with other WRKY TFs, we found that MbWRKY3 has a high identity to the WRKY TFs
Summary
Plants are frequently exposed to variable environmental stresses, such as drought, salt, heat, chilling, pathogen attack, and nutrient deprivation, which adversely affect plant growth, development, and productivity (Gong & Liu 2013). Environmental stresses are perceived and transduced through a chain of signaling molecules that affect regulatory element of stress-inducible genes to initiate the synthesis of different classes of protein including transcription factors, enzymes, molecular chaperons, ion channels, and transporters or alter their activities (Mukhopadhyay et al 2004). To avoid such deficiencies, plants have developed adaptable mechanisms to perceive external signaling networks and to manifest adaptive responses with appropriate physiological, cellular, and molecular changes (Liu et al 2014). Plants have evolved complex strategies to reduce potential damage of drought stress (Wang et al 2009)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
