Reactivation of a silenced minimal Mutator transposable element system following low-energy nitrogen ion implantation in maize.
In maize, Mutator transposable elements are either active or silenced within the genome. In response to environmental stress, silenced Mutator elements could be reactivated, leading to changes in genome structure and gene function. However, there is no direct experimental evidence linking environmental stress and Mutator transposon reactivation. Using a maize line that contains a single inactive MuDR and a lone nonautonomous Mutator element, a Mu1 insertion in the recessive reporter allele a1-mum2 in an inactive Mutator background, we directly assessed Mutator reactivation following low-energy nitrogen ion implantation. We observed that N(+) implantation decreased cytosine methylation in MuDR terminal inverted repeats and increased expression of mudrA and mudrB. Both changes were associated with increased transpositional activity of MuDR through reactivation of the inactive minimal Mutator transposable element system. This study provides direct evidence linking environmental stress agents and Mutator transposon mobilization in maize. In addition, the observed changes to DNA methylation suggest a new mechanism for mutations by low-energy ion implantation.
Qian
Yexiong
Y
Key Laboratory of Crop Biology, Anhui Agricultural University, Hefei, Anhui, China. qianyexiong@yahoo.com.cn
Cheng
Xiao
X
Liu
Yan
Y
Jiang
Haiyang
H
Zhu
Suwen
S
Cheng
Beijiu
B
D001483:Base Sequence; D015139:Blotting, Southern; D019175:DNA Methylation; D017931:DNA Primers; D004251:DNA Transposable Elements; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D018525:Germination; D009584:Nitrogen / Q000378:metabolism*; D011058:Pollen; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
D017931:DNA Primers; D004251:DNA Transposable Elements; D018744:DNA, Plant; D009584:Nitrogen