ALKBH10B confers drought tolerance by sustaining the expression of photosynthesis- and drought-related genes in Arabidopsis
Epitranscriptomic N6-methyladenosine m6A RNA modification has emerged as an important regulatory layer of gene expression and protein synthesis in plant stress adaptation. In this study, expression profiling revealed that drought stress induces a global reprogramming of the m6A machinery, with ALKBH10B being the most strongly up-regulated component. Hormone-related expression analyses and promoter-driven luciferase assays suggest that ABA induces ALKBH10B transcription via ABRE and MYB cis-elements, whereas JA alleviates this activation. Moreover, ALKBH10B overexpression plants (OX-1) accumulated WT levels of ABA under drought stress but displayed markedly reduced JA content, resulting in enhanced stomatal closure, improved water-use efficiency and thus an enhanced drought tolerance. Transcriptome analysis revealed that drought stress induces fewer transcriptional changes in OX-1 plants compared to WT and the drought-sensitive alkbh10b-1 mutant. Differential expression and GO enrichment analyses highlight that photosynthesis-related processes were most affected by ALKBH10B activity, correlating with preserved chlorophyll content and PSII efficiency in OX-1. The m6A-IP-qPCR showed that ALKBH10B directly demethylates specific photosynthesis-related and drought-responsive genes, thus promoting their sustained expression during stress. Moreover, genes associated with mitochondrial respiration and ATP synthesis were enriched in OX-1, indicating that ALKBH10B supports energy metabolism during drought. Together, our results reveal that ALKBH10B enhances drought tolerance by coordinating m6A-dependent post-transcriptional regulation to maintain photosynthetic capacity and mitochondrial ATP homeostasis, as well as fine-tuning ABA-JA crosstalk to optimize stomatal control.