title: Genome-wide transcriptome analysis reveals that cadmium stress signaling controls the expression of genes in drought stress signal pathways in rice.
abstract: 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 and ∼60,000 expressed transcripts, including transcripts that could not be characterized by microarray-based approaches, were evaluated. Upregulation of various ROS-scavenging enzymes, chelators and metal transporters demonstrated the appropriate expression profiles to Cd exposure. Gene Ontology enrichment analysis of the responsive transcripts indicated the upregulation of many drought stress-related genes under Cd exposure. Further investigation into the expression of drought stress marker genes such as DREB suggested that expression of genes in several drought stress signal pathways was activated under Cd exposure. Furthermore, qRT-PCR analyses of randomly selected Cd-responsive metal transporter transcripts under various metal ion stresses suggested that the expression of Cd-responsive transcripts might be easily affected by other ions. Our transcriptome analysis demonstrated a new transcriptional network linking Cd and drought stresses in rice. Considering our data and that Cd is a non-essential metal, the network underlying Cd stress responses and tolerance, which plants have developed to adapt to other stresses, could help to acclimate to Cd exposure. Our examination of this transcriptional network provides useful information for further studies of the molecular mechanisms of plant adaptation to Cd exposure and the improvement of tolerance in crop species.
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Youko
authors.initials: Y
authors.lastname: Oono
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan; New Project Development Division, Hitachi Government & Public Corporation System Engineering, Ltd, Koto-ku, Tokyo, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yazawa
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawahara
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanamori
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Kobayashi
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Mori
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Wu
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Handa
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Itoh
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsumoto
mesh_terms: D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D055864:Droughts; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D023281:Genomics; D005810:Multigene Family / Q000235:genetics; D012275:Oryza / Q000166:cytology / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D017423:Sequence Analysis, RNA; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics*; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D027682:Cation Transport Proteins; D002104:Cadmium