EARE-1, a Transcriptionally Active Ty1/Copia-Like Retrotransposon Has Colonized the Genome ofExcoecaria agallochathrough Horizontal Transfer.
Long terminal repeat (LTR) retrotransposons constitute the majority of the content of angiosperm genomes, but their evolutionary dynamics remain poorly understood. Here, we report the isolation and characterization of a putative full-length (~9550 bp) Ty1/copia-like retrotransposon inExcoecaria agallochaand its evolution in Euphorbiaceae. The so-calledEARE-1is phylogenetically closely related toRIRE-1fromOryza australiensis, and has proliferated recently (~7.19 Mya) in theE. agallochagenome. An RT-PCR analysis revealed substantial transcription ofEARE-1in all examined organs (leaves, staminate flowers, pistillate flowers, seeds, and roots) in unstressedE. agallochaplants and indications of elevated expression under stress. We conducted sequence analyses of 256 RT-RH fragments (~860 bp) ofEARE-1from 34 species representing four subfamilies of Euphorbiaceae that exist in China.EARE-1copies from twoExcoecariaspecies andPhyllanthus urinariashowed incongruent phylogeny with the host species and exhibited high sequence similarity to the host genes, suggesting a horizontal transfer fromP. urinariato the common ancestor ofExcoecaria. However, SSAP analysis detected no new insertions ofEARE-1among full-sibling progeny plants ofE. agallocha, despite considerable SSAP polymorphisms among half-siblings.EARE-1is the first transcriptionally active Ty1/copia-like retrotransposon isolated fromE. agallocha. Our results provide empirical evidence of the horizontal transfer of LTR retrotransposons in plants, and may suggest a significant role of post-transcriptional host control in the life cycles of transposable elements.
State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources School of Life Sciences, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, Sun Yat-sen University Guangzhou, China.
Jianhua
J
Huang
State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources School of Life Sciences, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, Sun Yat-sen University Guangzhou, China.
Yushuai
Y
Wang
State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources School of Life Sciences, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, Sun Yat-sen University Guangzhou, China.
Wenwen
W
Liu
State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources School of Life Sciences, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, Sun Yat-sen University Guangzhou, China.
Xu
X
Shen
State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources School of Life Sciences, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, Sun Yat-sen University Guangzhou, China.
Qiang
Q
Fan
South China Botanical Garden, Chinese Academy of Sciences Guangzhou, China.
Shuguang
S
Jian
State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources School of Life Sciences, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, Sun Yat-sen University Guangzhou, China.
Tian
T
Tang
Excoecaria agallocha; LTR retrotransposon; euphorbiaceae; horizontal transfer; transcriptional and transpositional activities