[SS14] Monitoring, Modelling and Predicting Biological Oscillations: From Genes to Ecosystems

[SS14-04] Evolution of coordinated gene expression in seasonal and tropical ecosystems

*Akiko Satake¹ (1. Kyushu University (Japan))

Keywords:

Phenology,Biological rhythm,Forest ecosystems,Transcriptomics,Environmental responses,Climate change

Understanding how plants respond to environmental change is essential for assessing forest vulnerability to climate change. Tropical species may be especially sensitive due to their narrower thermal tolerance, yet molecular studies on their responses remain limited. Using a molecular phenology approach, we examined the tropical tree Rubroshorea leprosula through biweekly transcriptome analysis in Malaysia (2017–2018). Gene expression clustering revealed strong responses to small temperature changes, particularly a decrease in photosynthetic genes and an increase in metabolic genes under lower minimum temperatures (~21°C). This response resembled that of two temperate species (Quercus glauca and Lithocarpus edulis) under winter conditions (~4.7°C), highlighting the heightened sensitivity of tropical species to minor temperature drops. Beyond individual responses, our research also addresses large-scale, synchronized flowering events observed in tropical and temperate forests—phenomena occurring at multi-year intervals across species. While such synchrony has been theorized to result from internal nutrient cycles and external water-stress signals, its molecular basis remains poorly understood. By generating genome-wide transcriptomic data from field samples, we revealed hierarchical synchrony in gene expression across tissues, individuals, and species. Distinct profiles were observed in leaves versus reproductive organs, with cross-species coherence in expression patterns during seasonal transitions. When gene expression synchrony aligns at the population level, it may drive feedback effects on local climate and reproductive success, illustrating a dynamic interaction between plant physiology and the broader ecosystem. These findings underscore the power of molecular phenology in uncovering both individual vulnerabilities and ecosystem-level synchrony.