Title: DNA methylation/demethylation programming during peach flower bud dormancy release, development and blooming Authors
Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 2012
Publication Date: February 11, 2013
Citation: Zhu, H., Chen, P., Xia, H., Callahan, A.M., Pellegrini, M., Liu, Z. 2013. DNA methylation/demethylation programming during peach flower bud dormancy release, development and blooming. Plant and Animal Genome Conference. Paper No. 9983. Technical Abstract: Peach flower bud development undergoes a long, complex and temperature-dependent regulation process with cessation of growth in response to cool temperatures in late fall, a slow but gradual development during the chilling period in winter, and eventually blooming in early spring. It has been demonstrated that the dormant flower buds absolutely require a certain period of accumulative chilling temperature prior to bud break, and warm temperatures for late development and blooming. Thus, chilling and heat requirements constitute unique and important regulatory features for peach flower bud. In this study, we took a deep sequencing approach to investigate epigenetic mechanisms underlying the chilling and heating requirement of peach flower buds. We identified over 2,400 differentially methylated genome regions (DMRs) in the buds before and after chilling treatment, with 75 percent of them up-methylated and 25 percent down-methylated, indicating that the chilling temperature is primarily correlated with increased DNA methylation. We also identified over 17,000 DMRs during the late developmental period between the times that the chilling requirement is met and bloom. Of the total DMRs identified, 7,201 are located in repetitive and intergenic regions while 10,195 are in intragenic regions, many of which are located in promoter regions. During bloom, we found that 97 percent of the total DMRs identified are down-methylated while only 3 percent of them are up-methylated, in contrast to that observed during chilling treatment. Our study provides evidence that a robust demethylation program occurs during late flower development and bloom, which is further supported by the transcriptome analysis of a number of genes which are directly and indirectly involved in DNA demethylation and methylation. The potential biological significance of this work will be discussed.