“Photosynthetic and Genetic Adaptations Underpinning the Resilience ofCistanthe longiscapain the Atacama Desert”

Abstract

SummaryThe Atacama Desert is one of the most hostile environments for life. However, the plant speciesCistanthe longiscapa(C. longiscapa) completes its life cycle in the Atacama Desert after sporadic rainfall.Physiological analyses under controlled environmental conditions revealed superior photosynthetic performance, better light acclimation mechanisms, and larger accumulation of photosystem II inC. longiscapacompared to its mesophilic sister species.C. longiscapashows evolutionary expansions in gene families related to DNA repair, photosynthesis, and protein homeostasis. In addition, we observed substantial gene duplication and polymorphic variations between coastal and inland populations in the Atacama Desert. Finally, our assembled mitochondrial genome provides genetic information for all DNA-containing compartments ofC. longiscapa.Diurnal oscillations of malic acid and time-resolved transcriptome analyses of plants harvested in the Atacama Desert indicate thatC. longiscapaengages in CAM metabolism. We observed significant differences in transcripts encoding plastid-localized proteins, including those involved in carbon metabolism, light harvesting, and photoprotection, highlighting the critical role of chloroplasts in the adaptation ofC. longiscapato the Atacama Desert.Our study provides physiological and genetic evidence for the adaptations ofC. longiscapaand advances our understanding of how plants can cope with extreme environmental conditions.