Analyses of the complete genome and gene expression of chloroplast of sweet potato [Ipomoea batata]

PLoS One. 2015 Apr 15;10(4):e0124083. doi: 10.1371/journal.pone.0124083. eCollection 2015.

Abstract

Sweet potato [Ipomoea batatas (L.) Lam] ranks among the top seven most important food crops cultivated worldwide and is hexaploid plant (2n=6x=90) in the Convolvulaceae family with a genome size between 2,200 to 3,000 Mb. The genomic resources for this crop are deficient due to its complicated genetic structure. Here, we report the complete nucleotide sequence of the chloroplast (cp) genome of sweet potato, which is a circular molecule of 161,303 bp in the typical quadripartite structure with large (LSC) and small (SSC) single-copy regions separated by a pair of inverted repeats (IRs). The chloroplast DNA contains a total of 145 genes, including 94 protein-encoding genes of which there are 72 single-copy and 11 double-copy genes. The organization and structure of the chloroplast genome (gene content and order, IR expansion/contraction, random repeating sequences, structural rearrangement) of sweet potato were compared with those of Ipomoea (L.) species and some basal important angiosperms, respectively. Some boundary gene-flow and gene gain-and-loss events were identified at intra- and inter-species levels. In addition, by comparing with the transcriptome sequences of sweet potato, the RNA editing events and differential expressions of the chloroplast functional-genes were detected. Moreover, phylogenetic analysis was conducted based on 77 protein-coding genes from 33 taxa and the result may contribute to a better understanding of the evolution progress of the genus Ipomoea (L.), including phylogenetic relationships, intraspecific differentiation and interspecific introgression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biological Evolution
  • Chloroplasts / genetics*
  • Chromosome Mapping
  • Gene Dosage
  • Gene Expression Regulation, Plant*
  • Gene Flow
  • Genes, Plant*
  • Genome, Chloroplast*
  • High-Throughput Nucleotide Sequencing
  • Inverted Repeat Sequences
  • Ipomoea batatas / classification
  • Ipomoea batatas / genetics*
  • Molecular Sequence Annotation
  • Open Reading Frames
  • Phylogeny
  • Plant Proteins / genetics*
  • Ploidies
  • RNA Editing

Substances

  • Plant Proteins

Grants and funding

This work is supported by grants from the National Science & Technology Pillar Program of China (No. 2007BAD78B03, http://kjzc.jhgl.org/) and the ‘‘Eleventh-Five’’ Key Project of Sichuan Province, China (No. 07SG111-003-1, http://www.scst.gov.cn/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.