SRA

Plant growth is severely affected by toxic concentrations of the non-essential heavy metal cadmium (Cd). Comprehensive transcriptome analysis by RNA-Seq following cadmium exposure is required to further understand plant responses to Cd and facilitate future systems-based analyses of the underlying regulatory networks. In this study, rice plants were hydroponically treated with 50 µM Cd for 24 hours. In total, ~60,000 transcripts, including transcripts that could not be characterized by microarray-based approaches, were evaluated and ~36,000 transcripts were responsive to Cd exposure. Among multigenic families that may protect cells from generated ROS and reduce Cd toxicity, prominently upregulated antioxidant enzyme genes were identified. Furthermore, 168 different metal ion transporter genes, which might mediate the transport of transition Cd, responded to Cd exposure. qRT-PCR analysis of randomly selected genes indicated that their expression changed obviously after exposure to various heavy metal stresses. The Cd responsive genes included many abiotic stress (drought, high-salinity, low temperature) responsive genes. Based on further investigation into the expression patterns of abiotic stress regulatory genes such as DREB, part of the signal transduction pathway for Cd exposure was determined to cross-talk with abiotic stress signaling pathways. Our results provide useful information for further studies of the molecular mechanisms of plant adaptation to Cd exposure and the improvement of Cd tolerance in crop species.