IDENTIFICATION AND CHARACTERIZATION OF PSWRKY1 INVOLVED IN THE ABIOTIC STRESS RESPONSES OF POLYGONATUM SIBIRICUM (SOLOMON’S SEAL).

WRKY protein is an important transcription factor in response to abiotic stress in plants. However, a systematic identification and characterization of WRKY genes has not been carried out for the medicinal plant Polygonatum sibiricum that has a strong ability to resist various abiotic stresses. In this study, we isolated a novel WRKY gene from P. sibiricum and compared its sequence structure with other plants. PsWRKY1 possesses two typical WRKY domains and two C₂H₂ zinc-finger motifs. Evolutionary analysis indicated that PsWRKY1 is most closely related to the WRKY protein from Eucalyptus grandis. Expression analysis showed that expression levels of PsWRKY1 were induced by cold and drought stresses but not salt stress. Overexpression of PsWRKY1 in Arabidopsis improved the seed germination and growth conditions of transgenic plants under drought and cold stresses. Furthermore, SOD activity and proline content in transgenic plants were higher than those in WT under cold and drought stresses, whereas MDA levels and relative electrolyte leakage in transgenic plants were lower than those in WT under same stresses. These results indicated that PsWRKY1 improved the tolerance to cold and drought stresses. This study is significant for understanding the molecular mechanism behind P. sibiricum cold and drought stresses tolerance. [ABSTRACT FROM AUTHOR]