Isolation and Functional Analysis of VvWRKY28, a Vitis vinifera WRKY Transcription Factor Gene, with Functions in Tolerance to Cold and Salt Stress in Transgenic Arabidopsis thaliana

Abstract

The grape (<i>Vitis vinifera</i> L.) not only has a long history of cultivation, but also has rich nutritional value and high economic value. However, grapes often face many threats in the growth process. For example, low temperature and salt stress restrict the growth status, yield, and geographical distribution of grapes. WRKY, as one of the largest transcription factor (TF) families in plants, participates in the response of plants to stress. <i>VvWRKY28</i>, a new zinc finger type transcriptional regulator gene, was isolated from Beichun (<i>V. vinifera</i> × <i>V.amurensis</i>) in this study. From the subcellular localization results, it can be concluded that <i>VvWRKY28</i> was localized in the nucleus. The expression of <i>VvWRKY28</i> was enriched in leaves (young and mature leaves), and cold and high salt conditions can induce high expression of <i>VvWRKY28</i>. After being transferred into <i>Arabidopsis</i>, <i>VvWRKY28</i> greatly improved the tolerance of <i>Arabidopsis</i> to low temperature and high salt and also changed many physiological and biochemical indicators of transgenic <i>Arabidopsis</i> to cope with cold and high salt stimulation. The content of malondialdehyde (MDA) was decreased, but for chlorophyll and proline, their content increased, and the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were improved. In addition, under cold stress, binding with cis-acting elements promotes the expression of downstream genes related to cold stress (<i>RAB18</i>, <i>COR15A</i>, <i>ERD10</i>, <i>PIF4</i>, <i>COR47</i>, and <i>ICS1</i>). Moreover, it also plays an active role in regulating the expression of genes related to salt stress (<i>NCED3</i>, <i>SnRK2.4</i>, <i>CAT2</i>, <i>SOD1</i>, <i>SOS2</i>, and <i>P5CS1</i>) under salt stress. Therefore, these results provide evidence that <i>VvWRKY28</i> may play a role in the process of plant cold and salt stress tolerance.