Metabolic signatures provide novel insights to Picrorhiza kurroa adaptation along the altitude in Himalayan region

Abstract

Introduction: Along the altitude, environmental conditions vary significantly that might influence plant performance and distribution. Adaptation to these changing conditions is a complex biological process that involves reprogramming of genes, proteins and metabolites. The metabolic response of medicinal plants along the altitude has been less explored yet.

Objectives: In the present study, we investigated the adaptation strategies of Picrorhiza kurroa Royle ex Benth. along the altitude in organ specific manner using metabolomic approach.

Methods: Picrorhiza kurroa plants at flowering stage were randomly sampled from three altitudes viz. 3400, 3800 and 4100 masl in the Himalayan region. Leaf, root and rhizome were used for LC-MS based non-targeted metabolite profiling and targeted analysis of sugars, amino acids, picrosides and their corresponding phenolic acids.

Results: A total of 220, primary and secondary metabolites (SMs) were identified (p < 0.05) representing an extensive inventory of metabolites and their spatial distribution in P. kurroa. Differential accumulation of metabolites suggests source-sink carbon partitioning, occurrence of partial TCA cycle, ascorbate metabolism, purine catabolism and salvage route, pyrimidine synthesis, lipid alteration besides gibberellins and cytokinin inhibition might be an adaptive strategy to alpine environmental stress along the altitude. Further, marked differences of organ and altitude specific SMs reflect alteration in secondary metabolic pathways. Significant accumulation of picrosides suggests their probable role in P. kurroa adaptation.

Conclusion: This study provides a platform that would be useful in deciphering the role of metabolites considered to be involved in plant adaptation.

Keywords: Adaptation; Altitude gradient; Metabolomics; Picrorhiza kurroa; Picrosides; Secondary metabolites.