Genome-Wide Investigation of N6-Methyladenosine Regulatory Genes and Their Roles in Tea (Camellia sinensis) Leaves During Withering Process.

Chen Zhu,Siyi Xie,Guangwu Chen,Caiyun Tian,Yuling Lin,Kai Xu,Zhongxiong Lai,Shuting Zhang,Chengzhe Zhou,Yuqiong Guo

doi:10.3389/fpls.2021.702303

Chen Zhu, Siyi Xie + Show 8 more

Open Access

https://doi.org/10.3389/fpls.2021.702303

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Abstract

N6-methyladenosine (m6A), one of the internal modifications of RNA molecules, can directly influence RNA abundance and function without altering the nucleotide sequence, and plays a pivotal role in response to diverse environmental stresses. The precise m6A regulatory mechanism comprises three types of components, namely, m6A writers, erasers, and readers. To date, the research focusing on m6A regulatory genes in plant kingdom is still in its infancy. Here, a total of 34 m6A regulatory genes were identified from the chromosome-scale genome of tea plants. The expansion of m6A regulatory genes was driven mainly by whole-genome duplication (WGD) and segmental duplication, and the duplicated gene pairs evolved through purifying selection. Gene structure analysis revealed that the sequence variation contributed to the functional diversification of m6A regulatory genes. Expression pattern analysis showed that most m6A regulatory genes were differentially expressed under environmental stresses and tea-withering stage. These observations indicated that m6A regulatory genes play essential roles in response to environmental stresses and tea-withering stage. We also found that RNA methylation and DNA methylation formed a negative feedback by interacting with each other’s methylation regulatory genes. This study provided a foundation for understanding the m6A-mediated regulatory mechanism in tea plants under environmental stresses and tea-withering stage.

Highlights

Methylation, one of the representative epigenetic modifications, can directly influence gene expression and function without altering the gene sequence
30 m6A regulatory genes were randomly distributed on 13 chromosomes, and the remaining four genes were located on the unanchored contigs (Figure 4)
We found that segmental duplication and whole-genome duplication (WGD) events are the main contributors to the expansion of m6A regulatory genes

Summary

Introduction

Methylation, one of the representative epigenetic modifications, can directly influence gene expression and function without altering the gene sequence. Extensive studies have shown that methylation occurs on DNAs and. RNA Methylation in Tea Plant on RNAs (Fu et al, 2014; Yang et al, 2018). Similar to DNA methylation, recent studies have shown that m6A modification within multiple types of RNAs is a dynamic and reversible process. Writers and erasers are involved in adding or removing methyl groups to the conserved sequence. In addition to these two pivotal proteins, the third proteins (m6A readers) recognize m6A marks and perform the specific biological functions of m6A-modified RNAs. In general, writers, erasers, and readers form a sophisticated regulatory system that guides the formation, removal, and decoding of m6A modifications

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