Arsenic Stress-Related F-Box (ASRF) gene regulates arsenic stress tolerance in Arabidopsis thaliana

Arsenic (As), a non-biodegradable contaminant, is extremely toxic to plants and animals in its inorganic form. As negatively affects plant growth and development, primarily by inducing oxidative stress through redox imbalance. Here we characterized the Arabidopsis F-box protein gene AT2G16220 (Arsenic Stress-Related F-box (ASRF)) that we identified in the genome-wide association study. The asrf mutant seedlings showed high sensitivity to arsenate (As-V) stress. As-V significantly affected asrf seedling growth when germinated on or exposed to As-V-supplemented growth regimes. As-V stress significantly induced production of reactive oxygen species and proline accumulation in asrf, so the asrf maintained high proline content, possibly for cellular protection and redox homeostasis. Heterozygous seedlings (Col-0 x asrf, F1 progeny) were relatively less affected by As-V stress than asrf mutant but showed slightly reduced growth compared with the Col-0 wild type, which suggests that the homozygous ASRF locus is important for As-V stress resistance. Transcriptome analysis involving the mutant and wild type revealed altered phosphate homeostasis in asrf seedlings, which implies that ASRF is required for maintaining phosphate and cellularhomeostasis under excess As-V. Our findings confirm the roles of ASRF in As stress tolerance in plants, for a novel way to mitigate arsenic stress.