Oeosporangium elegans Adapts to Desiccated State Upon Reprogramming Metabolism Through Redox Balance, Membrane Dynamics, and Protective Mechanisms

<title>Abstract</title> <p> Desiccation tolerance (DT) in plants involves complex metabolic reprogramming that enables survival under severe water deficit conditions. In this study, a comparative metabolomic analysis was conducted to investigate metabolic shift between hydrated and desiccated states of <italic>Oeosporangium elegans</italic> . A total of 798 metabolites were identified, out of which 268 (33.6%) were unique to the hydrated state, 298 (37.3%) were specific to the desiccated state, and 232 (29.1%) were common to both conditions with differential abundance. Pathway enrichment analysis revealed that metabolites of the hydrated stage participate in biosynthetic and growth-associated pathways, including carbohydrate metabolism, nucleotide biosynthesis, and flavonoid biosynthesis. In the desiccated stage, the profile shifted toward stress-responsive metabolism, with enrichment of riboflavin metabolism, pyrimidine metabolism, and biosynthesis of unsaturated fatty acids. Pathways supporting redox homeostasis, membrane stabilization, and molecular repair under water deficit accompanied this shift. Although metabolite detected only in the desiccated stage, pheophorbide a, an intermediate of chlorophyll degradation, is proposed as a candidate biomarker of desiccation stress. Considering both stages together, the findings indicate that DT in <italic>Oeosporangium elegans</italic> depends on coordinated metabolic networks spanning redox balance, membrane dynamics, and protective mechanisms. </p>