Open AccessImpact of differential DNA methylation on transgene expression in cotton (Gossypium hirsutum L.) events generated by targeted sequence insertion
Author(s) -
Verkest Aurine,
Bourout Stephane,
Debaveye Jurgen,
Reynaert Kristine,
Saey Bernadette,
Brande Ilse Van,
D'Halluin Kathleen
Publication year - 2019
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.13049
Subject(s) - biology , transgene , dna methylation , genetics , gene , homologous recombination , gene silencing , dna , locus (genetics) , microbiology and biotechnology , gene expression
Summary Targeted Genome Optimization ( TGO ) using site‐specific nucleases to introduce a DNA double‐strand break ( DSB ) at a specific target locus has broadened the options available to breeders for generation and combination of multiple traits. The use of targeted DNA cleavage in combination with homologous recombination ( HR )‐mediated repair, enabled the precise targeted insertion of additional trait genes (2m epsps, hppd, axmi115 ) at a pre‐existing transgenic locus in cotton. Here we describe the expression and epigenome analyses of cotton Targeted Sequence Insertion ( TSI ) events over generations. In a subset of events, we observed variability in the level of transgene ( hppd , axmi115 ) expression between independent but genetically identical TSI events. Transgene expression could also be differential within single events and variable over generations. This expression variability and silencing occurred independently of the transgene sequence and could be attributed to DNA methylation that was further linked to different DNA methylation mechanisms. The trigger(s) of transgene DNA methylation remains elusive but we hypothesize that targeted DSB induction and repair could be a potential trigger for DNA methylation.