ALKBH10B, an mRNA m6A Demethylase, Modulates ABA Response During Seed Germination in Arabidopsis

Jun Tang,Hongchao Duan,Junbo Yang,Guifang Jia

doi:10.3389/fpls.2021.712713

Abstract

As the most abundant and reversible chemical modification in eukaryotic mRNA, the epitranscriptomic mark N6-methyladenine (m6A) regulates plant development and stress response. We have previously characterized that ALKBH10B is an Arabidopsis mRNA m6A demethylase and regulates floral transition. However, it is unclear whether ALKBH10B plays a role in abiotic stress response. Here, we found that the expression of ALKBH10B is increased in response to abscisic acid (ABA), osmotic, and salt stress. The alkbh10b mutants showed hypersensitive to ABA, osmotic, and salt stress during seed germination. Transcriptome analysis revealed that the expression of several ABA response genes is upregulated in alkbh10b-1 than that of wild type, indicating ALKBH10B negatively affects the ABA signaling. Furthermore, m6A sequencing showed that ABA signaling genes, including PYR1, PYL7, PYL9, ABI1, and SnRK2.2 are m6A hypermethylated in alkbh10b-1 after ABA treatment. Taken together, our work demonstrated that ALKBH10B negatively modulates ABA response during seed germination in Arabidopsis.

Highlights

N6-methyladenine (m6A) is the most abundant chemical modification in eukaryotic mRNA, and it is dynamically reversible (Jia et al, 2011; Zheng et al, 2013)
We found Abscisic acid (ABA), osmotic, and salt stress increase the expression of m6A demethylase ALKBH10B, which depends on ABA insensitive 1 (ABI1)
We found that transcription factors, ABI3 and ABI5, which are two well-known positive regulators of ABA signaling during seed germination, were upregulated in alkbh10b1 after ABA treatment (Figures 4, 5)

Summary

Introduction

N6-methyladenine (m6A) is the most abundant chemical modification in eukaryotic mRNA, and it is dynamically reversible (Jia et al, 2011; Zheng et al, 2013). The “writer” complex of RNA m6A mainly consists of three core subunits: METTL3 (methyltransferase like 3), METTL14, and WTAP (Wilms’ tumor 1-associating protein) (Liu et al, 2014; Ping et al, 2014). In Arabidopsis, the core subunits of RNA m6A methyltransferase complex includes MTA (homolog of human METTL3), MTB (homolog of human METTL14), and FIP37 (homolog of human WTAP). The core subunits of RNA m6A methyltransferase are essential proteins for embryonic development (Zhong et al, 2008; Shen et al, 2016; Ruzicka et al, 2017). There are 13 YTH domain proteins in Arabidopsis (Zhou et al, 2018)

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Discussion

Conclusion