The role of WRKY 15 in xylem development and salt response in Arabidopsis thaliana

Sammanfattning: Xylem is a water-conducting tissue in vascular plants, that absorbs water from the roots and distributes it throughout the compartments, providing the plant with essential water and nutrients for its cellular processes. The xylem, divided into protoxylem and metaxylem, develops differently according to the various abiotic circumstances, in which transcription factors have a crucial role. The transcription factor WRKY15 plays a part in the negative regulation of protoxylem differentiation and studies have shown that WRKY15 indirectly suppresses the master transcriptional regulator VND7 (VASCULAR RELATED NAC DOMAIN7), which has been observed to promote protoxylem differentiation. The transcription factor VND6 (VASCULAR RELATED NAC DOMAIN6) also plays a role in xylem differentiation, but instead as a master regulator in the metaxylem vessels. The aim of this study is to investigate the role of WRKY15 transcription factor in xylem development and salt response in the model plant Arabidopsis thaliana. In this thesis, I am looking at the expression of VND6, VND7, and WRKY15 in plants subjected to high salinity and water deficiency, and the connection between them. In order to investigate this aspect, analysis was done using qPCR and GUS staining. Results from the experiments suggested that the increased expression of WRKY15 is an early response to salinity, and occurs in different locations in the root based on the environment.