title: Transpositional reactivation of two LTR retrotransposons in rice-Zizania recombinant inbred lines (RILs).
abstract: Hybridization is prevalent in plants, which plays important roles in genome evolution. Apart from direct transfer and recombinatory generation of genetic variations by hybridization, de novo genetic instabilities can be induced by the process per se. One mechanism by which such de novo genetic variability can be generated by interspecific hybridization is transpositional reactivation of quiescent parental transposable elements (TEs) in the nascent hybrids. We have reported previously that introgressive hybridization between rice (Oryza sativa L.) and Zizania latifolia Griseb had induced rampant mobilization of three TEs, a copia-like LTR retrotransposon Tos17, a MITE mPing and a class II TE belonging to the hAT superfamily, Dart/nDart. In this study, we further found that two additional LTR retrotransposons, a gypsy-like (named RIRE2) and a copia-like (named Copia076), were also transpositionally reactivated in three recombinant inbred lines (RILs) derived from introgressive hybridization between rice and Z. latifolia. Novel bands of these two retroelements appeared in the RILs relative to their rice parental line (cv. Matsumae) in Southern blot, suggestive of retrotransposition, which was substantiated by transposon display (TD) and locus-specific PCR amplification for insertion sites. Both elements were found to be transcribed but at variable levels in the leaf tissue of the parental line and the RILs, suggesting that transcriptional control was probably not a mechanism for their transpositional activity in the RILs. Expression analysis of four genes adjacent to de novo insertions by Copia076 revealed marked difference in the transcript abundance for each of the genes between the RILs and their rice parental line, but the alterations in expression appeared unrelated with the retroelement insertions.
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE, Institute of Genetics and Cytology, Northeast Normal University, Changchun, PR China.
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Wang
authors.forename: Qin
authors.initials: Q
authors.lastname: Tian
authors.forename: Yi-Qiao
authors.initials: YQ
authors.lastname: Ma
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.forename: Gao-Jian
authors.initials: GJ
authors.lastname: Miao
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Dong-Hui
authors.initials: DH
authors.lastname: Cao
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wang
authors.forename: Chunjing
authors.initials: C
authors.lastname: Lin
authors.forename: Jingsong
authors.initials: J
authors.lastname: Pang
authors.forename: Bao
authors.initials: B
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D054458:Amplified Fragment Length Polymorphism Analysis; D001483:Base Sequence; D032461:Chromosomes, Plant / Q000235:genetics; D056915:DNA Copy Number Variations; D020869:Gene Expression Profiling; D017343:Genes, Plant; D006824:Hybridization, Genetic; D007178:Inbreeding; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology / Q000235:genetics*; D012194:RNA-Directed DNA Polymerase / Q000737:chemistry; D011995:Recombination, Genetic; D018626:Retroelements; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D020079:Terminal Repeat Sequences; D015533:Transcriptional Activation
chemical_list: D018626:Retroelements; D012194:RNA-Directed DNA Polymerase