Ecophysiolomic analysis of stress tolerant Himalayan shrub Hipppophae rhamnoides shows multifactorial acclimation strategies induced by diverse environmental conditions.

Climatic fluctuations are a major global concern, affecting the agronomic productivity of plants. Hippophae rhamnoides a naturally growing stress tolerant Himalayan shrub was chosen to understand its stress hardiness mechanism. Comparative proteomic and biochemical analysis were done for pooled berry populations (HrB13 and HrB14) growing in two different environmental conditions. HrB13, growing under sub-optimal environmental conditions exhibited differential abundance of stress responsive proteins, which were the rate limiting enzymes associated with stress-responsive metabolic pathways, including Xanthine dehydrogenase (reactive oxygen species [ROS] signaling), Farnesyl diphosphate synthase (phenylpropanoid pathway), endosomal BRO-1 domain protein (ultraviolet [UV]-light stress), Phosphofructokinase (sugar metabolism) and Ubiquitin thioesterase (protein alterations). Biochemical investigations showed a positive correlation between proteomic plasticity (HrB13) and 1.6 to 15-fold accumulation of downstream adaptive metabolic signatures like enzymes and antioxidants involved in ROS scavenging pathways (Catalase, Ascorbate peroxidase, Glutathione reductase, ascorbate and glutathione content), secondary metabolites (phenolics, flavonoids, carotenoids) and polyunsaturated fatty acids (∝ - linolenic acid and linoleic acid). Interactome and KEGG pathway analysis also supported interactions of differentially accumulated proteins with stress-responsive signaling components involved in physiological pathways associated with stress tolerance. This is the first 'ecophysiolomics' study, showing the response of seabuckthorn to multiple stress conditions via activation of multifactorial acclimation strategies leading to morphological, metabolic and physiological modifications, resulting in dark orange berries in HrB13. Higher accumulation of omega-6 fatty acids, carotenoids and ascorbate during suboptimal growth conditions, provides exciting prospects for enhancing pharmaceutical properties of seabuckthorn berries, emphasizing need to analyze diversity of plant signaling mechanisms under changing climate conditions.