Remodeling of membrane lipids associated with ABA-induced desiccation tolerance in Physcomitrium patens.

Pretreatment of Physcomitrium patens with abscisic acid (ABA) has been shown to induce desiccation tolerance. While previous research suggests that ABA-induced production of proteins and soluble sugars contributes to desiccation stress tolerance, additional mechanisms underlying this tolerance remain unclear. In this study, we found that ABA pretreatment led to increased levels of digalactosyl diacylglycerol (DGDG), phosphatidylcholine (PC), and phosphatidylinositol (PI), along with a decrease in monogalactosyl diacylglycerol (MGDG). These changes elevated the MGDG/DGDG and PC/phosphatidylethanolamine (PE) ratios, potentially stabilizing membranes and enhancing desiccation tolerance. Furthermore, ABA pretreatment effectively prevented membrane lipid degradation during desiccation and subsequent rehydration. These findings highlight ABA's role in desiccation tolerance through membrane lipid modulation, providing new insights into stress tolerance mechanisms in bryophytes.