How a Tiny RNA Tag Shapes Drought Tolerance, Flowering and Crop Yield

Deep inside every plant cell, a chemical tag is being written, read and erased on messenger RNA molecules at astonishing speed. The tag, N6-methyladenosine, or m6A, is a methyl group deposited on the sixth nitrogen atom of adenosine bases, and it has emerged as one of the most consequential post-transcriptional regulators in the plant kingdom. A new review published in Plant Cell Reports by Mei Yang, Dingjie Wu, Zijian Hu, Jinxing Lin, Ye Li and Ruili Li of Beijing Forestry University, working with colleagues at Peking University’s Beijing Advanced Center of RNA Biology, assembles the molecular machinery, developmental roles and crop-improvement potential of this modification into a single conceptual framework. The authors argue that the field is now poised to move from descriptive epitranscriptomics toward trait-oriented crop and forest tree improvement, a shift with implications for drought tolerance, salt resistance, male fertility, pollen viability and fruit maturation in agronomically important species.

The modification operates through three classes of proteins that the review describes in detail. Writers, the methyltransferase complexes, install m6A marks on RNA; erasers, the demethylases, remove them; and readers, the m6A-binding proteins, interpret the marks and translate them into concrete fates for the tagged transcript. In Arabidopsis, the core writer centers on the methyltransferase MTA, the plant homolog of the mammalian METTL3 subunit, together with FIP37, FIONA1 and the conserved E3 ubiquitin ligase HAKAI, which was identified as a required factor for m6A mRNA methylation in Arabidopsis. Recent work has added two zinc finger proteins that interact with HAKAI and function in m6A writing, indicating that the writer complex is more elaborate than once assumed. On the eraser side, the AlkB homolog demethylases ALKBH9B, ALKBH10B and related dioxygenases dynamically reverse the marks, while the reader side is dominated by YTH domain-containing proteins, including the ECT family, CPSF30-L, FLK and EHD6-associated factors, each with distinct transcript targets and cellular consequences.

What makes m6A so powerful is that the same mark can produce opposite outcomes depending on where it sits on an RNA and which reader encounters it. The review emphasizes that m6A dynamically modulates RNA stability, splicing and translation, the three pillars of post-transcriptional gene control. In Arabidopsis, m6A has been shown to inhibit local ribonucleolytic cleavage, thereby stabilizing mRNAs, while in other contexts it promotes transcript decay. The modification also influences alternative polyadenylation: the reader CPSF30-L recognizes m6A marks and controls polyadenylation site choice in liquid-like nuclear bodies, directing the processing of nitrate signaling-related gene transcripts. Adding another layer of complexity, the methyltransferase MTA deposits m6A on primary microRNA transcripts, modulating microRNA biogenesis itself, which means the writer can shape the small RNA regulatory landscape as well as the messenger RNA one.

One of the most striking discoveries highlighted in the review is that m6A-modified RNA can act as a molecular glue that drives liquid-liquid phase separation in plants. In rice, the RNA binding protein EHD6 recruits the m6A reader YTH07 and sequesters the OsCOL4 mRNA into phase-separated ribonucleoprotein condensates to promote flowering. In Arabidopsis, the reader ECT8 forms phase-separated condensates that mediate feedback regulation of abscisic acid perception, linking the physical chemistry of RNA condensates directly to hormone signaling. This condensate-based mechanism represents a fundamentally different way of thinking about how cells organize their RNA processing: rather than relying solely on discrete enzyme-substrate interactions, m6A marks can nucleate the formation of membraneless compartments that concentrate specific transcripts and processing factors in space and time.

The developmental consequences of this system are profound. In Arabidopsis, an m6A-YTH module controls developmental timing and morphogenesis, and the ECT2/ECT3/ECT4 axis is recurrently required for cell proliferation during organogenesis. The reader ECT2 controls trichome morphology by affecting mRNA stability and post-transcriptionally regulates proteasome activity. The demethylase ALKBH10B affects the floral transition, while the reader FLK regulates floral transition by modulating the stability and splicing of the flowering repressor FLC. The methyltransferase FIONA1 affects photomorphogenesis and flowering through its genome-wide methylation activity. Shoot stem cell fate is also under m6A control, with the modification regulating the balance between stem cell maintenance and differentiation in the shoot apical meristem. The review also notes that m6A methylation counteracts dark-induced leaf senescence in Arabidopsis, connecting RNA modification to the timing of organ aging.

Reproductive biology is particularly sensitive to m6A, and the review devotes substantial attention to this connection. In rice, m6A modification promotes auxin biosynthesis required for male meiosis, and feedback regulation of m6A creates local auxin maxima essential for microsporogenesis. The demethylase OsALKBH9 regulates tapetal programmed cell death and pollen exine accumulation, while OsEDM2L mediates m6A of the EAT1 transcript for proper alternative splicing and polyadenylation that governs tapetal degradation. The demethylase OsALKBH5 is required for double-strand break formation and repair during rice meiosis, affecting mRNA stability in the process. The translational regulator OseIF3h interacts with OsMTA2 to regulate plant growth and pollen development at the translational level. In strawberry, the FvABF3-FvALKBH10B-FvSEP3 cascade regulates fruit ripening, and in tomato, m6A methylomes reveal regulation of the DNA demethylase gene SlDML2 during fruit ripening. In kiwifruit, dynamic m6A methylation implicates AcALKBH10 in ripening-related quality regulation, and the reader SlYTH1 affects plant growth and fruit shape. Even ornamental traits are touched by this system, with m6A effects on multi-petalization in Magnolia wufengensis.

Stress resilience is where the agronomic promise of m6A becomes most tangible. The review documents that m6A modifications affect drought tolerance, salt resistance and quality traits across crops. In apple, the methyltransferase MdMTA enhances drought tolerance by promoting mRNA stability and translation efficiency of genes involved in lignin deposition and oxidative stress, while overexpression of the reader MhYTP1 enhances drought tolerance and water use efficiency by improving abscisic acid levels under drought. The reader MhYTP2 regulates MdMLO19 mRNA stability and antioxidant gene translation efficiency, conferring powdery mildew resistance, and also contributes to hypoxia tolerance by regulating MdERF54 mRNA stability. In cotton, m6A modification regulates drought response in a calcium- and ABA-dependent manner, and the demethylase GhALKBH10 negatively regulates salt tolerance. In switchgrass, the reader SiYTH1 enhances drought tolerance by affecting mRNA stability of genes related to stomatal closure and reactive oxygen species scavenging. In poplar, m6A methylation positively regulates salt stress response, and drought induces epitranscriptome and proteome changes in the stem-differentiating xylem of Populus trichocarpa. In sweet sorghum, a methylase and demethylase pair regulates salt tolerance by mediating m6A modification, and in wheat, transcriptome-wide m6A methylation profiles reveal potential roles in drought response. In wild emmer wheat, the writer TdFIP37 is involved in salt stress, and in maize, the ZmABF4-ZmVIL2/ZmFIP37 module enhances drought tolerance in seedlings.

The review also connects m6A to genome defense and viral interactions, expanding its biological scope beyond development and stress. RNA m6A modification facilitates DNA methylation during maize kernel development, revealing crosstalk between RNA and DNA epigenetic layers. In Arabidopsis, RNA m6A regulates the transcription and heterochromatin state of retrotransposons, positioning the modification as a guardian of genome integrity. The demethylase AtALKBH9B promotes mobilization of a heat-activated long terminal repeat retrotransposon, showing that erasers can activate mobile genetic elements under specific conditions. In viral contexts, Arabidopsis m6A demethylase activity modulates infection by plant viruses and the m6A abundance in their genomic RNAs, while in rice, the dynamics of m6A modification mediate interactions between the plant and invading viruses. The demethylase ALKBH9B plays a critical role in the vascular movement of alfalfa mosaic virus in Arabidopsis, and nanopore RNA direct sequencing has identified that m6A modification is essential for sorbitol-controlled resistance to Alternaria alternata in apple, tying the modification to pathogen defense through multiple independent routes.

Detection technology is advancing rapidly, and the review surveys the tools that are making this progress possible. Antibody-based m6A-seq and its transcriptome-wide derivatives have mapped methylomes in dozens of species, from Arabidopsis to sea buckthorn, revealing unique features of plant m6A topology, including enrichment near the 3′ end of transcripts. Nanopore direct RNA sequencing, which reads native RNA molecules through an array of nanopores, enables detection of RNA modifications by comparative analysis without amplification, and has been applied to profile m6A and poly(A) tail length changes in moso bamboo induced by gibberellin. Most transformative, programmable RNA editing with CRISPR/dCas13 systems now allows targeted m6A modification at specific transcripts in plants, with dCas13a and dCas13(Rx) derived systems enabling dynamic, site-specific methylation and demethylation. The review also notes screening of candidate chemical regulators for the m6A writer MTA in Arabidopsis, opening the door to small-molecule control of the epitranscriptome. These technologies provide the precision needed to dissect cause and effect at individual transcript resolution rather than at the level of genome-wide correlation.

The authors frame their synthesis as a conceptual framework for moving plant m6A research from descriptive epitranscriptomics toward trait-oriented crop and forest tree improvement. The evidence they assemble suggests that manipulating writer, reader and eraser activities could tune developmental timing, stress resilience and quality traits in crops, with field trials already showing that RNA demethylation increases the yield and biomass of rice and potato plants. The interplay between m6A and hormone signaling, particularly abscisic acid, auxin and gibberellin, provides mechanistic entry points for breeding programs that seek to combine stress tolerance with yield stability. As detection methods sharpen and programmable editing matures, the epitranscriptome is transitioning from a layer of gene regulation that scientists could only observe to one they can engineer, and the review positions plant biology at the center of that transition, with implications for food security, forest restoration and the design of crops suited to a changing climate.

Subject of Research: RNA N6-methyladenosine modifications in plants: molecular mechanisms and biological roles

Article Title: RNA N6-methyladenosine modifications in plants: molecular mechanisms and biological roles

Article References: Yang, M., Wu, D., Hu, Z., Lin, J., Li, Y., & Li, R. (2026). RNA N6-methyladenosine modifications in plants: molecular mechanisms and biological roles. Plant Cell Reports, 45(11), 336. https://doi.org/10.1007/s00299-026-04020-3

Image Credits: AI Generated

DOI: 10.1007/s00299-026-04020-3

Keywords: N6-methyladenosine, modifications, plants, molecular, mechanisms, biological, roles, scientific research