High Salinity Induces Changes in the Leaf Transcriptome of Withania somnifera

Abstract Withania somnifera , commonly referred to as Indian Ginseng, is a medicinally important plant that can be found in many regions of the world, such as South Africa and India. Withanolides are key secondary metabolites responsible for conferring the plant its unique medicinal properties. The reaction of W. somnifera to salt stress, in particular the possible effects on its withanolide production, has yet to be explored. Under salt stress, germination efficiency dropped by 17.8% and caused physiological damage to emerging roots. A transcriptome analysis of salt-stressed leaves revealed the differential regulation of 3048 transcripts, with gene ontology analysis indicating an increased transcript abundance associated with phenylpropanoid, plant hormone signaling, detoxification response, concomitant with reduced growth, energy metabolism, and protein modification. Most withanolide pathway genes were significantly downregulated. Notably, 26 transcription factor families, particularly AP2/ERF, NAC, GRAS, and HB-WOX members, as well as 10 Late Embryogenesis-Abundant members, predominantly dehydrins, were significantly differentially regulated, suggesting their potential involvement in the salt stress response of W. somnifera . This study provides valuable insights into the molecular responses of W. somnifera to salt stress, highlighting potential targets for future research and subsequently for withanolide production, which has vast potential in the pharmaceutical industry.