FATIMA TUZ ZAHRA (Kyungpook national univeristy)

Sunghwan Kim (Kyungpook national univeristy)

FATIMA TUZ ZAHRA (Kyungpook national univeristy)

Syahril Sulaiman (Korea Polar Research Institute)

Kyungwon Min (Korea Polar Research Institute)

Hyounseok Lee (Korea Polar Research Institute)

Sunghwan Kim (Kyungpook national univeristy)

Antarctic mosses tolerate prolonged freezing and dehydration, yet as regional drying intensifies, the metabolic basis of species-specific drought tolerance and recovery remains poorly understood. Here, we utilize a high-resolution mass spectrometry technique to establish spatial metabolomic baseline across the apical, intermediate, and basal shoot zones of three Antarctic moss species, Chorisodontium aciphyllum, Polytrichastrum alpinum (PA), and Sanionia uncinata (SU). Our findings reveal that apical tissues were enriched in AMP, tricarboxylic acid-cycle intermediates, zeaxanthin, and antheraxanthin, reflecting active energy metabolism and photoprotection. Intermediate tissues contained increased stress-associated flavonoids, whereas basal tissues accumulated raffinose-family oligosaccharides as osmoprotectants. Controlled drought–rehydration experiments were then conducted on PA and SU to assess whether this spatial metabolite organization was associated with species-specific drought responses and recovery. The PA moss appeared to be more drought-tolerant as it maintained relatively stable central metabolism, accumulated protective carbohydrates including raffinose, trehalose, and melezitose, and restored metabolic homeostasis following rehydration. In contrast, SU accumulated AMP, UMP, and inosine during drought and retained elevated abscisic acid and carbohydrate imbalances after rehydration, indicating greater energetic stress and incomplete recovery. The enrichment of osmoprotectants in basal tissues under field conditions, together with their sustained accumulation in drought-tolerant PA, suggests that basal tissues may serve as protective carbohydrate reservoirs that buffer metabolic disruption and promote recovery. In the absence of xylem and phloem, vertical metabolic gradients may contribute to resource storage and coordinated stress protection. These findings link shoot-zone metabolic profiling with species-specific drought resilience and provide a metabolomic baseline for monitoring climate-driven changes in Antarctic moss communities

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