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Identification of miRNA858 long-loop precursors in seed plants.

Wen-Qiu WangXiao-Fen LiuYong-Jing ZhuJia-Zhen ZhuChao LiuZhi-Ye WangXing-Xing ShenAndrew C AllanXue-Ren Yin
Published in: The Plant cell (2024)
MicroRNAs (miRNAs) are a class of nonprotein-coding short transcripts that provide a layer of post-transcriptional regulation essential to many plant biological processes. MiR858, which targets the transcripts of MYB transcription factors, can affect a range of secondary metabolic processes. Although miR858 and its 187-nt precursor have been well studied in Arabidopsis (Arabidopsis thaliana), a systematic investigation of miR858 precursors and their functions across plant species is lacking due to a problem in identifying the transcripts that generate this subclass. By re-evaluating the transcript of miR858 and relaxing the length cut-off for identifying hairpins, we found in kiwifruit (Actinidia chinensis) that miR858 has long-loop hairpins (1,100 to 2,100 nt), whose intervening sequences between miRNA generating complementary sites were longer than all previously reported miRNA hairpins. Importantly, these precursors of miR858 containing long-loop hairpins (termed MIR858L) are widespread in seed plants including Arabidopsis, varying between 350 and 5,500 nt. Moreover, we showed that MIR858L has a greater impact on proanthocyanidin and flavonol levels in both Arabidopsis and kiwifruit. We suggest that an active MIR858L-MYB regulatory module appeared in the transition of early land plants to large upright flowering plants, making a key contribution to plant secondary metabolism.
Keyphrases
  • cell proliferation
  • transcription factor
  • long non coding rna
  • long noncoding rna
  • arabidopsis thaliana
  • climate change
  • dna binding
  • single cell