Genomics enabled breeding approaches for improving cadmium stress tolerance in plants

Heavy metal (HM) toxicity is a considerable challenge that the current agricultural production systems and human population face worldwide. Among the HMs with pronounced toxic effects, cadmium (Cd) potentially contaminates a range of vital agricultural resources including soil and water together with severely impacting crop performance. Besides, gradual accumulation of Cd in food chain poses a global threat to food safety and environmental sustainability. Plants are equipped with meticulously orchestrated physiological and molecular mechanisms to respond and acclimatize to Cd-challenged scenarios. However, limited understanding about the HM toxicity mechanism involving metal uptake/transport, associated candidate gene (s) or QTLs and signaling crosstalk has greatly constrained breeding capacities to improve plants for HM tolerance. In the context, quantifying genetic variation for Cd tolerance accompanied by appropriate breeding schemes allowing the most efficient utilization of the estimated variation should be essentially undertaken. Concurrently, efforts are needed to facilitate fast-track introgression of genomic segments harboring candidate gene(s)/QTL for Cd tolerance to high yielding yet Cd-susceptible backgrounds. Advances in plant molecular biology have introduced refined techniques and methods to pinpoint genetic factors describing plant Cd tolerance. Ancillary to conventional breeding and marker assisted selection methods are modern transgenic technologies that offer attractive means to precisely interrogate the relevant molecular networks and manipulate the key Cd-related genes in plants.