Executive Summary : | The presence of heavy metals (HM) in medicinal herbs is a critical issue for the phytopharma industry due to restrictions on their usage and transport. Recently, phytoexclusion has received increasing attention as an alternative and practical approach to finding out the low HM accumulating cultivars/genotypes. This strategy involves the selection and use of crop cultivars with low HM accumulation in their harvestable parts to minimize the health risks of HM-polluted farmland. Involvement of differential mechanisms for internal metal tolerance was suggested among the genotypes, which include restriction or exclusion, translocation to the shoot, and restriction of metal movement across the plasmalemma. The process also includes the activation of genes related to enzymatic and non-enzymatic antioxidative defence systems, related modifications in transcript concentration, and the production of secondary metabolites. The differential accumulation of metals depends upon the ecophysiology of plants, which involved the ionomics of cultivars/genotypes, cation exchange capacity of the root, transportation of metals to xylem, and then subcellular distribution. Besides, Different HM had different uptake mechanisms in the plant such as arsenate (AsV) via phosphate (P) transporters, arsenite (AsIII) through aquaglyceroporins, and Cd and Pb by ZIP transporters. In addition, at co-existence of As with Pb and Cd in soil, the interactive toxicity of different metals such as synergistic, antagonistic, and additive also. The understanding of these mechanisms of phytoexclusion in different genotypes/cultivars is in the infancy stage and needs to explore. In CSIR-CIMAP, the screening of low and high accumulating genotypes/accession of Andrographis paniculata was already done for As, Pb, and Cd. The present study aims to understand the differential mechanism of Cd, Pb, and As accumulation and tolerance in screened low and high accumulating genotypes of Andrographis Paniculata under single and co-exposure of HM. The objectives of the study are to evaluate the HM uptake and translocation and sub cellular distribution in single and multi-metal exposure at different time and concentration in high and low accumulating genotypes/accessions of Andrographis paniculata. The kinetic study will provide information about the metal affinity for different tissues and subcellular parts and additive, synergistic and antagonistic effects on co exposure of metals (As, Cd and Pb). The applicable threshold for selected low heavy metal accumulating genotypes of A. paniculata under different soil types ( having different pH and availability of metals) will be done and compared with the data obtained from the kinetic study. Findings from this study could provide a scientific insight into the impact of mixed metal exposure on plant metabolism. The low metal accumulating genotypic A.paniculata could be used for safe cultivation with minimal risk to human health. |
Co-PI: | Dr. Ashutosh Kumar Shukla, CSIR-Central Institute of Medicinal and Aromatic Plants (CIMAP), Lucknow, Uttar Pradesh-226015, Dr. Karuna Shanker, CSIR-Central Institute of Medicinal and Aromatic Plants (CIMAP), Lucknow, Uttar Pradesh-226015 |