These authors contributed equally to this work.
Epigenetic modification contributes to the expression divergence of three TaEXPA1 homoeologs in hexaploid wheat (Triticum aestivum)
Article first published online: 29 JAN 2013
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
Volume 197, Issue 4, pages 1344–1352, March 2013
How to Cite
Hu, Z., Han, Z., Song, N., Chai, L., Yao, Y., Peng, H., Ni, Z. and Sun, Q. (2013), Epigenetic modification contributes to the expression divergence of three TaEXPA1 homoeologs in hexaploid wheat (Triticum aestivum). New Phytologist, 197: 1344–1352. doi: 10.1111/nph.12131
- Issue published online: 4 FEB 2013
- Article first published online: 29 JAN 2013
- Manuscript Accepted: 25 NOV 2012
- Manuscript Received: 30 OCT 2012
- Major Program of the National Natural Science Foundation of China. Grant Numbers: 31290210, 31290212
- National Basic Research Program of China. Grant Number: 2012CB910903
- National Science Foundation for Distinguished Young Scholars. Grant Number: 30925023
- DNA methylation;
- epigenetic modification;
- expression divergence;
- hexaploid wheat;
- histone modification;
- Common wheat is a hexaploid species with most of the genes present as triplicate homoeologs. Expression divergences of homoeologs are frequently observed in wheat, as well as in other polyploid plants. However, the mechanisms underlying this phenomenon are poorly understood.
- Expansin genes play important roles in the regulation of cell size, as well as organ size. We found that all three TaEXPA1 homoeologs were silenced in seedling roots. In seedling leaves, TaEXPA1-A and TaEXPA1-D were expressed, but TaEXPA1-B was silenced. Further analysis revealed that silencing of TaEXPA1-B in leaves occurred after the formation of the hexaploid.
- Chromatin immunoprecipitation assays revealed that the transcriptional silencing of three TaEXPA1 homoeologs in roots was correlated with an increased level of H3K9 dimethylation and decreased levels of H3K4 trimethylation and H3K9 acetylation. Reactivation of TaEXPA1-A and TaEXPA1-D expression in leaves was correlated with increased levels of H3K4 trimethylation and H3K9 acetylation, and decreased levels of H3K9 dimethylation in their promoters, respectively. Moreover, a higher level of cytosine methylation was detected in the promoter region of TaEXPA1-B, which may contribute to its silencing in leaves.
- We demonstrated that epigenetic modifications contribute to the expression divergence of three TaEXPA1 homoeologs during wheat development.