De Novo Transcriptome Assembly and Differential Gene Expression Analysis of the Global Invader Thunbergia alata Under Varying Light Conditions

Abstract

Biological invasions threaten tropical biodiversity, yet the molecular mechanisms underlying successful invaders remain poorly understood. Thunbergia alata (Black-eyed Susan) is an aggressive “genomic orphan” invader in Andean forests, causing significant ecological disruption. This study contributes as one of the few transcriptomic profiles of light vs. shade responses in T. alata, providing a foundational molecular resource for this species. We performed differential expression analysis under varying light conditions, revealing a massive transcriptomic shift involving over 4000 differentially expressed genes. Our findings suggest a robust and stable homeostatic adaptation mechanism, characterized by the up-regulation of SnRK1 subunits for energy sensing and strategic management of Reactive Oxygen Species (ROS) within the thylakoid membrane. Furthermore, the fine-tuning of PIF/Auxin modules and the condition-specific induction of NAC and WRKY transcription factors facilitate shade avoidance and rapid vertical growth. The identification of a substantial reservoir of species-specific “not classified” genes suggests that novel genetic elements contribute to T. alata’s adaptive success. By elucidating these key regulatory networks, this research provides an important genomic baseline for future studies on adaptive evolution and the development of molecularly informed strategies for managing and controlling this invasive species in new environments.