Pre-meiotic 21-nucleotide reproductive phasiRNAs emerged in seed plants and diversified in flowering plants

Nat Commun. 2021 Aug 16;12(1):4941. doi: 10.1038/s41467-021-25128-y.


Plant small RNAs are important regulatory elements that fine-tune gene expression and maintain genome integrity by silencing transposons. Reproductive organs of monocots produce abundant phased, small interfering RNAs (phasiRNAs). The 21-nt reproductive phasiRNAs triggered by miR2118 are highly enriched in pre-meiotic anthers, and have been found in multiple eudicot species, in contrast with prior reports of monocot specificity. The 24-nt reproductive phasiRNAs are triggered by miR2275, and are highly enriched during meiosis in many angiosperms. Here, we report the widespread presence of the 21-nt reproductive phasiRNA pathway in eudicots including canonical and non-canonical microRNA (miRNA) triggers of this pathway. In eudicots, these 21-nt phasiRNAs are enriched in pre-meiotic stages, a spatiotemporal distribution consistent with that of monocots and suggesting a role in anther development. Although this pathway is apparently absent in well-studied eudicot families including the Brassicaceae, Solanaceae and Fabaceae, our work in eudicots supports an earlier singular finding in spruce, a gymnosperm, indicating that the pathway of 21-nt reproductive phasiRNAs emerged in seed plants and was lost in some lineages.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Fragaria / genetics
  • Fragaria / metabolism
  • Gene Expression Regulation, Plant
  • Magnoliopsida / metabolism*
  • Meiosis
  • MicroRNAs / genetics
  • Nucleotides / metabolism*
  • Phylogeny
  • Picea / genetics
  • Plant Proteins / genetics
  • RNA, Double-Stranded / metabolism
  • RNA, Plant / genetics*
  • RNA, Small Interfering / metabolism*
  • Seeds / metabolism*
  • Solanaceae / metabolism
  • Transcriptome


  • MicroRNAs
  • Nucleotides
  • Plant Proteins
  • RNA, Double-Stranded
  • RNA, Plant
  • RNA, Small Interfering