After transcription, a messenger RNA (mRNA) is further post‐transcriptionally regulated by several features including RNA secondary structure and covalent RNA modifications (specifically N6‐methyladenosine, m6A). Both RNA secondary structure and m6A have been demonstrated to regulate mRNA stability and translation and have been independently linked to plant responses to soil salinity levels. However, the effect of m6A on regulating RNA secondary structure and the combinatorial interplay between these two RNA features during salt stress response has yet to be studied. Here, we globally identify RNA‐protein interactions and RNA secondary structure during systemic salt stress. This analysis reveals that RNA secondary structure changes significantly during salt stress, and that it is independent of global changes in RNA‐protein interactions. Conversely, we find that m6A is anti‐correlated with RNA secondary structure in a condition‐dependent manner, with salt‐specific m6A correlated with a decrease in mRNA secondary structure during salt stress. Taken together, we suggest that salt‐specific m6A deposition and the associated loss of RNA secondary structure results in increases in mRNA stability for transcripts encoding abiotic stress response proteins and ultimately increases in protein levels from these stabilized transcripts. In total, our comprehensive analyses reveal important post‐transcriptional regulatory mechanisms involved in plant long‐term salt stress response and adaptation.
Plants respond to low temperatures by altering the mRNA abundance of thousands of genes contributing to numerous physiological and metabolic processes that allow them to adapt. At the post‐transcriptional level, these cold stress‐responsive transcripts undergo alternative splicing, microRNA‐mediated regulation and alternative polyadenylation, amongst others. Recently, m6A, m5C and other mRNA modifications that can affect the regulation and stability of RNA were discovered, thus revealing another layer of post‐transcriptional regulation that plays an important role in modulating gene expression. The importance of m6A in plant growth and development has been appreciated, although its significance under stress conditions is still underexplored. To assess the role of m6A modifications during cold stress responses, methylated RNA immunoprecipitation sequencing was performed in Arabidopsis seedlings esposed to low temperature stress (4°C) for 24 h. This transcriptome‐wide m6A analysis revealed large‐scale shifts in this modification in response to low temperature stress. Because m6A is known to affect transcript stability/degradation and translation, we investigated these possibilities. Interestingly, we found that cold‐enriched m6A‐containing transcripts demonstrated the largest increases in transcript abundance coupled with increased ribosome occupancy under cold stress. The significance of the m6A epitranscriptome on plant cold tolerance was further assessed using the
- Award ID(s):
- 1849708
- NSF-PAR ID:
- 10369884
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 111
- Issue:
- 4
- ISSN:
- 0960-7412
- Page Range / eLocation ID:
- p. 1052-1068
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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