Metabolomic indicators for low-light stress in seagrass

摘要

Monitoring of seagrass meadows is essential to inform adaptive management and address widespread declines in seagrass ecosystems. Effective monitoring techniques require sensitive indicators that are capable of detecting sub-lethal stressors and differentiating stress responses from background environmental variation. Here we explore untargeted metabolomics as a means to measure multi-parameter molecular responses of seagrass to low-light stress. We subjected Zostera muelleri to reduced light scenarios ( 10% natural light) in a six-week field experiment. Biomass loss was quantified over time and leaf samples were analysed by Nuclear Magnetic Resonance (NMR) spectroscopy to explore the effect of low-light exposure on metabolic activity. We identified several potential bioindicators of low-light stress: a reduction of soluble sugars and their derivatives, glucose, fructose, sucrose and myo-inositol, N-methylnicotinamide, organic acids and various phenolic compounds, and an increase in some amino acids. These signals were evident even amongst a noisy background of environmental variation and are consistent with inhibition of photosynthesis. Metabolite profiles showed a more consistent response to low-light stress than to biomass loss. These results suggest that metabolomics measurements may be useful bio-indicators of low-light stress in seagrass and that molecular indicators could inform on management of seagrass ecosystems.