WRKY transcription factors play important roles in regulating biotic and abiotic stresses. University of Chinese Academy of Sciences' Wenqi Bao, along with colleagues, recently found a WRKY gene from Japanese knotweed (Polygonum cuspidatum), PcWRKY33, that encodes a nucleoprotein, which specifically binds to the promoter of target genes to regulate their expression.
Analysis shows that expression of PcWRKY33 is induced by various abiotic stresses, including salt stress and plant hormones. Overexpression of PcWRKY33 in Arabidopsis thaliana reduced its tolerance to salt stress. Specifically, a number of physiological parameters in the transgenic lines were significantly lower under salt stress.
The transgenic plants also exhibited decreased expression of stress-related genes, increased accumulation of reactive oxygen species (ROS), and decreased activities of ROS-scavenging enzymes. These suggest that PcWRKY33 negatively regulates salt tolerance by downregulating stress-related genes and increasing the level of ROS.
These results indicate that PcWRKY33 is involved in abiotic stress regulation.

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