Relationship between ionomics and transcriptomics of rice plant in response to arsenite stress

Abstract

Paddy rice cultivated in flooded fields tends to accumulate more arsenic than other terrestrial crops. Ionomic profiling and transcriptomic variations of rice plants were investigated to understand the molecular mechanism used to counteract arsenite [As(III)] stress. The total concentrations of 29 elements in the rice shoots and roots under control and As(III) stress conditions were determined by inductively coupled plasma mass spectrometry (ICP-MS). Ionomic differences between rice tissues under different conditions were identified through principal component analysis. Compared to their external conditions, the genomic composition plays a more important role in rice ionomics. In the transcriptome analyses, a total of 3812 differentially expressed genes (DEGs) were identified in the As(III)-treated shoots compared to the control shoots. The significant DEGs generated by gene ontology enrichment analysis were mainly associated with transmembrane transporters and ion binding, which were directly correlated with ionomics. Upregulation of transporter genes correlated with nutrient elements was observed, indicating that the rice plants tended to translocate more nutrients, such as potassium, phosphate and ammonium, to cope with As(III) toxicity. Transcriptomics also showed overexpression of aquaporins and ABC transporters for detoxification of As(III) in rice plants. Further investigation is necessary for a deeper insight into the molecular mechanism involved in the ionomics of rice plants.