The Role of Polyamines on the Production of Volatile Secondary Metabolite in Coriandrum sativum L.

Abstract

Polyamines are small organic cationic compounds with two or more amines. Common polyamines include putrescine (PUT), spermidine (SPD), and spermine (SPM). Polyamines are crucial for plants growth and development, as they significantly impact various physiological processes and stress responses. Their influence on the synthesis of secondary metabolites is vital for plant defense and adaptation. Methylglyoxal-bis (guanylhydrazone) (MGBG) is an inhibitor that blocks the synthesis of SPD and SPM polyamines, affecting plant growth by modulating polyamine levels. Scientists have studied the role of polyamines and MGBG in plant growth and secondary metabolite production, but their role in the production of volatile secondary metabolites in Coriandrum sativum L. remains critically unexplored. Aim: The present study investigates the role of polyamines (PUT, SPD, SPM) and MGBG in secondary metabolite production. The untargeted metabolomic analysis was used to study metabolites produced in different treatments. Method: Coriandrum sativum L. was selected as an experimental model to study the effect of polyamines. It was first cultured using a royal bliss variety of seeds in basal MS medium; the in vitro grown coriander was cultured in seven different treatments (Basal MS (control), Putrescine, Spermidine, Spermine, MGBG, MGBG + Spermidine, MGBG + Spermine), each treatment has 100μM of concentration, and later the plantlets were collected and metabolomic study was done. Untargeted metabolomics was done using the GC-MS technique, and metabolites were identified for each treatment. Later, metabolites were mapped using the PubChem database. Subclass enrichment analysis, biosynthetic metabolic pathway and one-factor statistical analysis were evaluated using the MetaboAnalysyt (6.0) tool. 2 Results: Spermidine gives a significant increase in no. of branches, all three PAs enhanced the length of branches, and MGBG-treated three treatments (MGBG, MGBG+SPD, MGBG+SPM) significantly decreased the root length. MGBG+SPD treatment enhanced the metabolites and their abundance and significantly enriched the retinoids class of metabolites. The PUT, SPD, and MGBG treatments showed an increased enrichment ratio of different alkaloids. Fatty acids biosynthesis pathway is significantly impacted in all treatments; Phenylalanine, tyrosine, and tryptophan biosynthesis pathways were impacted in PUT and SPM treatment, betalain biosynthesis was highly impacted in MGBG, MGBG+SPM treatment and isoquinoline alkaloid biosynthesis pathway was highly impacted in MGBG + SPD treatment. Conclusion: Polyamine treatment significantly improves plant growth, while MGBG, MGBG+SPD and MGBG+SPM enhance the secondary metabolite production and the major metabolic pathways involved in metabolite synthesis, including alkaloids, carotenoids, and betalain. This study helps to understand the role of PAs in plant growth and secondary metabolite production.