title: Laser Irradiation-Induced DNA Methylation Changes Are Heritable and Accompanied with Transpositional Activation ofmPingin Rice.
abstract: DNA methylation is an integral component of the epigenetic code in most higher eukaryotes. Exploring the extent to which DNA methylation can be altered under a specific condition and its heritability is important for elucidating the biological functions of this epigenetic modification. Here, we conducted MSAP analysis of rice plants with altered phenotypes subsequent to a low-dose Nd3+YAG laser irradiation. We found that all four methylation patterns at the 5'-CCGG sites that are analyzable by MSAP showed substantial changes in the immediately treated M0 plants. Interestingly, the frequencies of hypo- and hypermethylation were of similar extents, which largely offset each other and render the total methylation levels unchanged. Further analysis revealed that the altered methylation patterns were meiotically heritable to at least the M2 generation but accompanied with further changes in each generation. The methylation changes and their heritability of the metastable epigenetic state were verified by bisulfite sequencing of portion of the retrotranspon,Tos17, an established locus for assessing DNA methylation liability in rice. Real-time PCR assay indicated that the expression of various methylation-related chromatin genes was perturbed, and a Pearson correlation analysis showed that many of these genes, especially two AGOs (AGO4-1andAGO4-2), were significantly correlated with the methylation pattern alterations. In addition, excisions of a MITE transposon,mPing, occurred rampantly in the laser irradiated plants and their progenies. Together, our results indicate that heritable DNA methylation changes can be readily induced by low-dose laser irradiation, and which can be accompanied by transpostional activation of transposable elements.
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal UniversityChangchun, China; School of Life Sciences, Jilin Agricultural UniversityChangchun, China.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Li
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University Changchun, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Xia
authors.affiliation: College of Oceanology & Food Science, Quanzhou Normal University Quanzhou, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University Changchun, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yu
authors.affiliation: College of Agronomy, Jilin Agricultural University Changchun, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Ma
authors.affiliation: College of Agronomy, Jilin Agricultural University Changchun, China.
authors.forename: Hongping
authors.initials: H
authors.lastname: Kou
authors.affiliation: Jilin Academy of Agricultural Sciences Changchun, China.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Lin
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University Changchun, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University Changchun, China.
authors.forename: Bao
authors.initials: B
authors.lastname: Liu
keywords: DNA methylation; Nd3+YAG laser irradiation; epigenetic inheritance; rice; transposable elements