UV exposure drives biochemical and proteomic profile remodeling in Coffea canephora

UV radiation drives adaptation and acclimation via biochemical and physiological mechanisms. UV is a relevant environmental signal that modulates plant physiology, while excessive UV acts as a stress factor. To test the ability of Coffea canephora to acclimate to UV levels, young coffee plants were cultivated for six months in a mini greenhouse under either near ambient (UVam) or reduced (UVre) UV conditions. Afterwards, analyses of the changes in metabolic reprogramming and in UV-response proteins from leaf proteome profile were performed, including antioxidant enzymes (e.g., ascorbate peroxidase, APX;, Cu,Zn-superoxide dismutase, Cu,Zn-SOD; glutathione reductase, GR; catalase, CAT), and proteins involved in repair, folding, and detoxification. UVam exposure induced the highest CAT and GR activities, but lower APX activity, suggesting a shift in ROS detoxification strategies, while Cu,Zn-SOD activity remained unchanged. The 817 proteins identified by proteomic analysis were categorized into: (1) accumulation patterns of the isoforms of the analyzed antioxidant enzymes, and (2) proteins involved in critical responses. Specific antioxidant isoforms reinforced the suggested mitigation of oxidative damage at UVam exposure, even though several isoforms remained unchanged. Comparative analysis identified 61 accumulated proteins, of which 31 were up-accumulated and 30 were down-accumulated between UVam/UVre comparison. These findings indicated that UVre conditions favored cellular homeostasis and energy conservation, whereas UVam induced proteomic shifts that support UV acclimation responses. Overall, the study revealed how C. canephora fine-tunes its antioxidant and proteostatic systems in response to UV variation, offering new insights into the molecular basis of acclimation in tropical crops.