StALKBH10B ‐Mediated RNA m 6 A Modification Inhibits Potato Salt Tolerance by Targeting Flavonoids and ABA Signalling Pathways

ABSTRACT N 6 ‐methyladenosine (m 6 A) is the most prevalent methylation modification present in mRNAs, which has been confirmed to participate in many developmental and biological processes. However, the biological function and specific regulatory mechanism of m 6 A modification in relation to salt tolerance of potato remain obscure. Here, we generated a transcriptome‐wide m 6 A map using salt‐resistant and salt‐sensitive potato varieties under salt stress conditions to uncover patterns of m 6 A methylation in the potato response to salt stress. MeRIP‐seq revealed that m 6 A is significantly enriched in the CDS region in potato, by recognising the conserved motifs including RRACH and URRUAY. Numerous differential m 6 A‐deposited transcripts have been identified, which were significantly enriched in ABA‐signalling and flavonoids biosynthesis pathway in two potato varieties after salt stress. Notably, a positive correlation was observed between the m 6 A enrichment and mRNA abundance based on combined analysis of MeRIP‐seq and mRNA‐seq. StALKBH10B was identified as an m 6 A demethylase for decreasing m 6 A modification levels, inhibiting mRNA stability and translation efficiency of ABA signal‐related genes ( StABF3, StAAO3 , and StZEP7 ) and flavonoids biosynthesis genes ( StPAL3 , StCHS , and StFLS ), and overexpression of StALKBH10B suppressed salt resistance in potato. Collectively, we uncover a novel mechanism of post‐transcriptional modification involved in affecting salt stress response in potato, via StALKBH10B‐mediated m 6 A demethylation on targeted transcripts in the ABA signalling and flavonoids biosynthesis pathway, thereby providing candidate genes for the breeding of stress‐tolerant potato cultivars.