How manganese affects rice cadmium uptake and translocation in vegetative and mature plants
Date
2024-04-19
Journal Title
Journal ISSN
Volume Title
Publisher
Plant and Soil
Abstract
Background and aims
Rice is prone to Cd uptake under aerobic soil conditions primarily due to the OsNramp5 Mn transport pathway. Unlike Cd, Mn availability in rice paddies decreases as redox potential increases. We tested whether increasing Mn concentrations in solution would decrease Cd accumulation in rice through competition between Mn and Cd for uptake and/or suppression of OsNramp5 expression.
Methods
Rice was grown to maturity under Mn concentrations that spanned three orders of magnitude (0.30 to 37 μM) that corresponded to free Mn2+ activities of 10–7.9 to 10–5.0 M while free Cd2+ activity was held as constant as achievable (10–10.2 to 10–10.4 M). Plant biomass and elemental concentrations were measured in roots and shoots at each stage. Fold changes in the expression of OsNramp5, OsCd1, OsHMA3, OsCCX2, and OsYSL6 genes in vegetative and grain-filling stages of rice plants were determined.
Results
Competition between Mn and Cd for root uptake and accumulation in shoots was observed at the highest concentration of Mn tested. OsNramp5 expression was significantly higher in rice plants at the vegetative stage compared to the grain-filling stage, while OsCd1 and OsHMA3 showed the opposite. Solution Mn concentrations previously thought to be tolerable by rice grown to the vegetative stage led to Mn toxicity as plants matured.
Conclusions
Mn competes with Cd during uptake into rice with OsNramp5 expression unaffected. Different translocation paths may occur for Mn and Cd within the rice plant and over the rice life cycle, with OsCCX2 correlated with shoot Cd concentration.
Description
This article was originally published in Plant and Soil. The version of record is available at: https://doi.org/10.1007/s11104-024-06669-9. © The Author(s) 2024
Keywords
Antagonism, Cadmium, growth stage, Manganese, OsNramp5, rice
Citation
Hu, R., Limmer, M.A. & Seyfferth, A.L. How manganese affects rice cadmium uptake and translocation in vegetative and mature plants. Plant Soil (2024). https://doi.org/10.1007/s11104-024-06669-9