Ulrike Bechtoldوردة عبدالعزيز الحقيل2022-05-292022-05-29https://drepo.sdl.edu.sa/handle/20.500.14154/44154Abstract Sugars play a key role as signalling molecules to regulate metabolism and development of plants but also play a critical role in response to abiotic stresses such as drought and high salinity . This study was conducted to investigate the role of DUF2358 in sugar signalling pathways under stress conditions which affect primary metabolism. For that, we investigated the role of DUF2358 in stress signaling pathways using knockout and overexpress mutants. Drought and prolonged dark treatments were carried out followed by analysis of gene expression, metabolites and plant phenotypes. Co-IP and a yeast-two-hybrid screens were performed to identify putative interacting proteins. We demonstrated that DUF258 is localised in the chloroplast likely attached to the thylakoid membrane. Changing DUF2358 expression had no effect on plant phenotype under optimal condition. However, under starvation conditions photosynthetic electron transport was affected. At the molecular level, ABA signalling pathways are induced in the knockout plants, which may be modulated through the interaction with CLPC1 and downstream induction of ABF4 and ABF1 expression. We suggest that DUF2358 may be involved in sensing the energy status of plants, triggering signaling pathways, such as dark-induced senescence. Many of the key components altered at the transcriptional level were kinases, and therefore future studies need to focus on the activity of the key kinases and their downstream targets to assess whether DUF2358 is truly involved in the communication between chloroplast energy status and well known sugar signaling pathways.en