Unraveling Molecular Biology of Aconites Biosynthesis in a Value Medicinal Herbs Aconitum Heterophyllum Wall

Abstract

Aconitum heterophyllum Wall Ranunculaceae popularly known as Atis is a biennial herb native to North Western and Eastern Himalayas of India. Its tuberous roots are commonly used as therapeutic ingredient in the Traditional Indian Medicinal System for curing dyspepsia abdominal pain diabetes and diarrhoea. Non toxic active components like atisine hetisine and heteratisine accumulating in tuberous roots of A. heterophyllum have wide pharmacological effects on immune digestive and nervous systems. Extensive harvesting for pharmaceutical purposes lack of organized cultivation and unorganized methods of uprooting has put this herb in the category of critically endangered species. No information exists as of today on molecular aspects of aconites biosynthesis, thereby, limiting genetic interventions towards genetic improvement of A. heterophyllum. Moreover the molecular components contributing to the formation of tuberous roots herbal biomass of A. heterophyllum are also lacking. The current study, therefore investigated 1 Identification of high aconites content accessions of A. heterophyllum. 2 Cloning and expression analysis of MVA MEP pathways genes vis-a-vis aconites content in A. heterophyllum. 3 Dissecting biosynthetic machinery of tuberous roots the herbal biomass of A. heterophyllum. newlineAtisine content ranged from 0.14-0.37 percent and total alkaloids aconites from 0.20-2.49 percent among 14 accessions of A. heterophyllum. Two accessions contained the highest atisine content with 0.30 percent and 0.37 percent as well as the highest alkaloids content with 2.22 percent and 2.49 percent respectively. No atisine was detected in leaves and shoots of A. heterophyllum, thereby, suggesting that the biosynthesis and accumulation of aconite alkaloids occur exclusively in roots. Quantitative expression analysis of 15 genes of MVA/MEP pathways in roots versus shoots, differing for atisine content 0-2.2 folds) showed 11-100 folds increase in transcript amounts of 4 genes of MVA pathway; HMGS, HMGR, PMK, IPPI, and 4 genes