Genome-wide DNA methylation changes associated with olfactory learning and memory in Apis mellifera

You Li,Zi-Long Wang,Yao Yi,Zhi-Jiang Zeng,Ya-Hui Guo,Zachary-Y Huang,Li-Zhen Zhang,Wan-Wan Hu

doi:10.1038/s41598-017-17046-1

You Li, Zi-Long Wang + Show 6 more

Open Access

https://doi.org/10.1038/s41598-017-17046-1

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Abstract

The honeybee is a model organism for studying learning and memory formation and its underlying molecular mechanisms. While DNA methylation is well studied in caste differentiation, its role in learning and memory is not clear in honeybees. Here, we analyzed genome-wide DNA methylation changes during olfactory learning and memory process in A. mellifera using whole genome bisulfite sequencing (WGBS) method. A total of 853 significantly differentially methylated regions (DMRs) and 963 differentially methylated genes (DMGs) were identified. We discovered that 440 DMRs of 648 genes were hypermethylated and 274 DMRs of 336 genes were hypomethylated in trained group compared to untrained group. Of these DMGs, many are critical genes involved in learning and memory, such as Creb, GABABR and Ip3k, indicating extensive involvement of DNA methylation in honeybee olfactory learning and memory process. Furthermore, key enzymes for histone methylation, RNA editing and miRNA processing also showed methylation changes during this process, implying that DNA methylation can affect learning and memory of honeybees by regulating other epigenetic modification processes.

Highlights

Honeybees (Apis mellifera) are social insects with important economic and ecological value due to their pollination services
DNA methylation tends to represses transcription of olfactory learning and memory related genes
Of the 714 differentially methylated regions (DMRs) of 963 genes, more DMRs were hypermethylated after training

Summary

Introduction

Honeybees (Apis mellifera) are social insects with important economic and ecological value due to their pollination services. By measuring the methylation of 30 memory associated genes in honeybees, Biergans et al.[23] found that, during memory formation process, memory associated genes are regulated by a temporally complex epigenetic mechanism. Even though it is known DNA methylation is involved in long-term memory formation in A. mellifera, the actual pattern of DNA methylation after learning and memory has not been studied in honeybees. Our results suggest extensive involvement of DNA methylation in honeybee olfactory learning and memory

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