Elevated CO2 and temperature influence key proteins and metabolites associated with photosynthesis, antioxidant and carbon metabolism in Picrorhiza kurroa.

Global warming is currently one of the most serious issues in ecology. Rising CO₂ level and temperature have begun to impact life cycles, distribution and yield of various plants yet, how medicinal plants will respond to changing environment is largely unknown. Picrorhiza kurroa Royle ex Benth. (Plantaginaceae) is a medicinal plant species that has been used for treatment of various diseases, particularly hepatic disease. Here, we have performed leaf and rhizome specific proteomic and metabolomic analysis to investigate the effect of elevated CO₂ and temperature on adaptive responses of P. kurroa. We observed differentially abundant proteins related to photosynthesis and carbon metabolism under free air carbon dioxide enhancement, whereas cytoskeleton proteins in free air temperature increase besides signaling, antioxidant, stress-responsive and chromatin remodeling proteins in both conditions. We also found an increased accumulation of metabolites, particularly picroside-I and picroside-II, sugars and sugar alcohol in rhizomes, whereas, decrease in picroside-I and increase in picroside-II content in leaves at FACE condition. Biochemical indices like total protein, phenolics, flavonoids and antioxidant activity were altered in a tissue-specific manner to elevated CO₂ and temperature. The results would provide new insights into possible adaptive mechanism, particularly in P. kurroa and medicinal plants in general. SIGNIFICANCE: Picrorhiza kurroa is an endangered medicinal plant of Himalayan region having immense medicinal values due to the presence of iridoid glycosides. This endangered plant species is particularly, more vulnerable to climate change. P. kurroa provides an opportunity to investigate the interaction between high altitude plant and their environment. Therefore, it will be essential to elucidate the adaptation mechanism at molecular level under e[CO₂] and e[t] conditions.The e[CO₂] and e[t] will likely alter the proteome and metabolite composition of plant and thereby, enhance plant adaptation. Proteomic and metabolomic studies would facilitate to explore the adaptive mechanism of P. kurroa which is poorly understood. Collectively, the findings will be helpful for better understanding of plant response to future CO₂ and temperature enriched environment and are of key importance to agriculture and ecosystem.