Convergent Isobilateral Leaves Increase the Risk for Mangroves Facing Human-Induced Rapid Environmental Changes.

Understanding plant adaptations in extreme environments is crucial, as these adaptations often confer advantages for survival. However, a significant gap exists regarding the genetic mechanisms underlying these adaptations and their responses to human-induced rapid environmental change (HIREC). This study addresses the question of whether genetic convergence occurs among plants with similar adaptive features, specifically focusing on isobilateral leaves in mangrove species. Here, we analyse the genetic convergence of isobilateral leaves in mangroves that have independently adapted to coastal intertidal zones. Our findings reveal that genetic convergence is evident in gene families involved in leaf abaxial and adaxial development, with strong selection pressures identified in photosynthesis and leaf polarity pathways. Despite these adaptations, mangrove species with isobilateral leaves occupy narrower ecological niches and face diminishing suitable habitat areas projected under various HIREC scenarios. These results indicate that while convergent traits enhance local adaptation, they may also increase vulnerability to ongoing environmental changes. This research provides valuable insight into the interplay between genetic adaptation and environmental resilience, underscoring the necessity for targeted biodiversity conservation strategies that safeguard specific adaptive traits amid rapid environmental shifts.