ABSTRACT: Trace concentrations of vanadium (V) have several benefits for plant growth, but high concentrations are toxic. To help characterize the cellular mechanisms underlying the toxic effects of V in plants, we present the first large-scale analysis of rice root responding to V during the early stages (1 and 3 h) of toxicity. Exposure to V triggered changes in the transcript levels of several genes related to cellular metabolic process, response to stimulus and transporters. Gene expression profiling revealed upregulated levels of genes associated with signaling and biosynthesis of auxin, abscisic acid (ABA) and jasmonic acid (JA) in V-treated rice roots. In addition, V upregulated the expression of ATP-dependent GSH-conjugated transport, ATP binding cassette (ABC) transporter, and markedly downregulated of the expression of divalent cation transporters, drug/metabolite transporter (DMT) and zinceiron permease (ZIP). Among the V-specific responsive transcription factors and protein kinases, the most predominant families were NAC (NAM, ATAF, CUC) transcription factor, receptor-like cytoplasmic kinase VII (RLCK-VII) and leucinerich repeat kinase VIII (LRR-VIII). These microarray data provide a new insight into the molecular mechanism of the rice roots response to V toxicity. Trace concentrations of vanadium (V) have several benefits for plant growth, but high concentrations are toxic. To help characterize the cellular mechanisms underlying the toxic effects of V in plants, we present the first large-scale analysis of rice root responding to V during the early stages (1 and 3 h) of toxicity. Exposure to V triggered changes in the transcript levels of several genes related to cellular metabolic process, response to stimulus and transporters. Gene expression profiling revealed upregulated levels of genes associated with signaling and biosynthesis of auxin, abscisic acid (ABA) and jasmonic acid (JA) in V-treated rice roots. In addition, V upregulated the expression of ATP-dependent GSH-conjugated transport, ATP binding cassette (ABC) transporter, and markedly downregulated of the expression of divalent cation transporters, drug/metabolite transporter (DMT) and zinceiron permease (ZIP). Among the V-specific responsive transcription factors and protein kinases, the most predominant families were NAC (NAM, ATAF, CUC) transcription factor, receptor-like cytoplasmic kinase VII (RLCK-VII) and leucinerich repeat kinase VIII (LRR-VIII). These microarray data provide a new insight into the molecular mechanism of the rice roots response to V toxicity.