title: Complex interplay among DNA modification, noncoding RNA expression and protein-coding RNA expression in Salvia miltiorrhiza chloroplast genome.
abstract: Salvia miltiorrhiza is one of the most widely used medicinal plants. As a first step to develop a chloroplast-based genetic engineering method for the over-production of active components from S. miltiorrhiza, we have analyzed the genome, transcriptome, and base modifications of the S. miltiorrhiza chloroplast. Total genomic DNA and RNA were extracted from fresh leaves and then subjected to strand-specific RNA-Seq and Single-Molecule Real-Time (SMRT) sequencing analyses. Mapping the RNA-Seq reads to the genome assembly allowed us to determine the relative expression levels of 80 protein-coding genes. In addition, we identified 19 polycistronic transcription units and 136 putative antisense and intergenic noncoding RNA (ncRNA) genes. Comparison of the abundance of protein-coding transcripts (cRNA) with and without overlapping antisense ncRNAs (asRNA) suggest that the presence of asRNA is associated with increased cRNA abundance (p<0.05). Using the SMRT Portal software (v1.3.2), 2687 potential DNA modification sites and two potential DNA modification motifs were predicted. The two motifs include a TATA box-like motif (CPGDMM1, "TATANNNATNA"), and an unknown motif (CPGDMM2 "WNYANTGAW"). Specifically, 35 of the 97 CPGDMM1 motifs (36.1%) and 91 of the 369 CPGDMM2 motifs (24.7%) were found to be significantly modified (p<0.01). Analysis of genes downstream of the CPGDMM1 motif revealed the significantly increased abundance of ncRNA genes that are less than 400 bp away from the significantly modified CPGDMM1motif (p<0.01). Taking together, the present study revealed a complex interplay among DNA modifications, ncRNA and cRNA expression in chloroplast genome.
authors.affiliation: IMPLAD PacBio Advanced Genomic Analysis Laboratory, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Haidian District, Beijing, P. R. China.
authors.forename: Haimei
authors.initials: H
authors.lastname: Chen
authors.affiliation: IMPLAD PacBio Advanced Genomic Analysis Laboratory, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Haidian District, Beijing, P. R. China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Pacific Biosciences, Menlo Park, California, United States of America.
authors.forename: George
authors.initials: G
authors.lastname: Yuan
authors.affiliation: IMPLAD PacBio Advanced Genomic Analysis Laboratory, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Haidian District, Beijing, P. R. China.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
mesh_terms: D001483:Base Sequence; D018744:DNA, Plant / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D054628:Genome, Chloroplast / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics; D059372:Nucleotide Motifs / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics*; D018515:Plant Leaves / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated / Q000235:genetics* / Q000378:metabolism; D015203:Reproducibility of Results; D027561:Salvia miltiorrhiza / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D059467:Transcriptome / Q000235:genetics
chemical_list: D018744:DNA, Plant; D012333:RNA, Messenger; D018749:RNA, Plant; D022661:RNA, Untranslated