Executive Summary : | Plant cells sense and respond to mechanical stimuli via mechanotransduction processes, which are driven by mechanosensitive (MS) ion channels. One of the most extensively characterized MS ion channels is MscS, which are non-selective ion channels activated by membrane tension. The homologs of MS channels, also known as MSLs (Mechanosensitive Ion Channel-Like proteins), have been found in all plant lineages, with 10 identified in A. thaliana. These MSLs are mostly involved in regulation of osmotic and oxidative stresses. To explore the functional conservation and regulatory mechanism during land plant evolution, an investigation into the sister lineage of angiosperms, namely bryophytes, is essential. Physcomitrium patens (moss) has been studied as a model system due to its short life cycle, easy culture conditions, and high amenability to genetic manipulations. In a preliminary Insilco analysis, 16 MSL genes (PpMSLs) were identified in the fully annotated P. patens genome using A. thaliana MSL gene sequences. The analysis revealed that 10 of these MSLs are differentially regulated when the gametophores were subjected to dehydration stress. Two P. patens MSL genes (PpMSL3, and PpMSL15) have distinctive expression patterns specific to the dehydration and rehydration conditions. The promoter of PpMSL3, and PpMSL15, house key dehydration and cold stress-related regulatory elements. This study aims to analyze the physiological function of these key motifs through promoter-reporter fusion assays coupled with sequential deletion of binding sites of the regulatory motifs in drought-subjected moss. |