title: Molecular characterization of the piggyBac-like element, a candidate marker for phylogenetic research of Chilo suppressalis (Walker) in China.
abstract: BACKGROUND
  Transposable elements (TEs, transposons) are mobile genetic DNA sequences. TEs can insert copies of themselves into new genomic locations and they have the capacity to multiply. Therefore, TEs have been crucial in the shaping of hosts' current genomes. TEs can be utilized as genetic markers to study population genetic diversity. The rice stem borer Chilo suppressalis Walker is one of the most important insect pests of many subtropical and tropical paddy fields. This insect occurs in all the rice-growing areas in China. This research was carried out in order to find diversity between C. suppressalis field populations and detect the original settlement of C. suppressalis populations based on the piggyBac-like element (PLE). We also aim to provide insights into the evolution of PLEs in C. suppressalis and the phylogeography of C. suppressalis.
  
  
  RESULTS
  Here we identify a new piggyBac-like element (PLE) in the rice stem borer Chilo suppressalis Walker, which is called CsuPLE1.1 (GenBank accession no. JX294476). CsuPLE1.1 is transcriptionally active. Additionally, the CsuPLE1.1 sequence varied slightly between field populations, with polymorphic indels (insertion/deletion) and hyper-variable regions including the identification of the 3' region outside the open reading frame (ORF). CsuPLE1.1 insertion frequency varied between field populations. Sequences variation was found between CsuPLE1 copies and varied within and among field populations. Twenty-one different insertion sites for CsuPLE1 copies were identified with at least two insertion loci found in all populations.
  
  
  CONCLUSIONS
  Our results indicate that the initial invasion of CsuPLE1 into C. suppressalis occurred before C. suppressalis populations spread throughout China, and suggest that C. suppressalis populations have a common ancestor in China. Additionally, the lower reaches of the Yangtze River are probably the original settlement of C. suppressalis in China. Finally, the CsuPLE1 insertion site appears to be a candidate marker for phylogenetic research of C. suppressalis.
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China. luogh_cn@163.com.
authors.forename: Guang-Hua
authors.initials: GH
authors.lastname: Luo
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China. xhli2012@163.com.
authors.forename: Xiao-Huan
authors.initials: XH
authors.lastname: Li
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China. zjhan@njau.edu.cn.
authors.forename: Zhao-Jun
authors.initials: ZJ
authors.lastname: Han
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China. guohf@jaas.ac.cn.
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Guo
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China. mlyangqiong@163.com.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China. wumin_au@163.com.
authors.forename: Min
authors.initials: M
authors.lastname: Wu
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China. zczhangjs@163.com.
authors.forename: Zhi-Chun
authors.initials: ZC
authors.lastname: Zhang
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China. liubsnj@126.com.
authors.forename: Bao-Sheng
authors.initials: BS
authors.lastname: Liu
authors.affiliation: Jiangsu Entry-Exit Inspection and Quarantine Bureau, Nanjing, 210001, China. kinglune@126.com.
authors.forename: Lu
authors.initials: L
authors.lastname: Qian
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China. fangjc@jaas.ac.cn.
authors.forename: Ji-Chao
authors.initials: JC
authors.lastname: Fang
mesh_terms: D000595:Amino Acid Sequence; D063147:Animal Distribution; D000818:Animals; D001483:Base Sequence; D002681:China; D004251:DNA Transposable Elements; D019143:Evolution, Molecular; D017344:Genes, Insect; D054643:INDEL Mutation; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics*; D010802:Phylogeny; D058974:Phylogeography; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: D004251:DNA Transposable Elements