Fig. 1. Phenotype and genetic basis analysis of wild type (WT) and hag1 mutant plants. A, Growth of WT and hag1 under 10 μmol/L As3+ stress for 3 d. Scale bar, 2 cm. B, Arsenic (As) concentrations in grains of hag1 and WT. C, As translocation from roots to shoots in WT and hag1 treated with 1 and 10 μmol/L As3+ for 7 d. Translocation of As from roots to shoots was represented as TFroot-to-shoot, and calculated as TFroot-to-shoot = Cshoot / Croot, where Cshoot and Croot are the As concentrations in shoots and roots (mg/kg) of rice plants, respectively. D, Concentrations of biothiol compounds in roots of WT and hag1. The concentrations of five biothiol compounds were analyzed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) after exposure to 1 and 10 μmol/L As3+ for 7 d. Cys, Cysteine; GSH, Glutathione; PC, Phytochelatin. E, Fine mapping of the OsABCC1 gene on chromosome (Chr.) 4, and its structure and mutation site. The red arrow indicates the mutation site. F, Differences in the coding sequences of Os04g52900 and its amino acid sequences between WT and hag1. G, PCR detection of transgenic rice seedlings. Marker is on the left. H, Phenotypes of 5-day-old plants of WT, hag1, and transgenic lines OsABCC1/hag1 after growth in a nutrient solution with 10 μmol/L As3+ for 3 d. Scale bar, 2 cm. I, As concentrations in grains of WT, hag1, and transgenic lines OsABCC1/hag1 grown in a paddy field containing 8.5 mg/kg of As. J, Heat map of differentially expressed genes (DEGs) involved in transport activity, stress response, and development. K, Relative expression levels of DEGs involved in As transport activity. L, Relative expression levels of OsABCC1 gene in selected indica and japonica rice varieties. Total RNA was extracted from the roots of the samples after exposure to 10 μmol/L As3+ for 7 d, and the ACTIN1 gene was used as an internal reference. M, Total As concentrations in grains of selected indica and japonica rice varieties. The samples were obtained after maturity. N, Relationship analysis between the OsABCC1 expression levels and corresponding As accumulation in grains among the selected rice varieties. Data represent Mean ± SD (n = 3). ** indicates P < 0.01. Means with different lowercase letters are significantly different (P < 0.05, Tukey’s test).