Plastic transport systems of rice for mineral elements in response to diverse soil environmental changes

Abstract

Climate change will increase frequency of drought and flooding, which threaten global crop productivity and food security. Rice (Oryza sativa) is unique in that it is able to grow in both flooded and upland conditions, which have large differences in the concentrations and chemical forms of mineral elements available to plants. To comprehensively understand the mechanisms of rice for coping with different water status, we performed ionomics and transcriptomics analysis of the roots, nodes and leaves of rice grown in flooded and upland conditions. Focusing the analysis on genes encoding proteins involved in transport functions for mineral elements, it was found that, although rice plants maintained similar levels of each element in the shoots for optimal growth, different transporters for mineral elements were utilised for nitrogen, iron, copper and zinc to deal with different soil water conditions. For example, under flooded conditions, rice roots take up nitrogen using transporters for both ammonium (OsAMT1/2) and nitrate (OsNPF2.4, OsNRT1.1A and OsNRT2.3), whereas under upland conditions, nitrogen uptake is mediated by different nitrate transporters (OsNRT1.1B and OsNRT1.5A). This study shows that rice possesses plastic transport systems for mineral elements in response to different water conditions (upland and flooding).