Synergy between the anthocyanin and RDR6/SGS3/DCL4 siRNA pathways expose hidden features of Arabidopsis carbon metabolism

Nat Commun. 2020 May 15;11(1):2456. doi: 10.1038/s41467-020-16289-3.


Anthocyanin pigments furnish a powerful visual output of the stress and metabolic status of Arabidopsis thaliana plants. Essential for pigment accumulation is TRANSPARENT TESTA19 (TT19), a glutathione S-transferase proposed to bind and stabilize anthocyanins, participating in their vacuolar sequestration, a function conserved across the flowering plants. Here, we report the identification of genetic suppressors that result in anthocyanin accumulation in the absence of TT19. We show that mutations in RDR6, SGS3, or DCL4 suppress the anthocyanin defect of tt19 by pushing carbon towards flavonoid biosynthesis. This effect is not unique to tt19 and extends to at least one other anthocyanin pathway gene mutant. This synergy between mutations in components of the RDR6-SGS3-DCL4 siRNA system and the flavonoid pathway reveals genetic/epigenetic mechanisms regulating metabolic fluxes.

Publication types

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

MeSH terms

  • Anthocyanins / metabolism*
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Base Sequence
  • Carbon / metabolism*
  • Gene Expression Regulation, Plant
  • Genes, Suppressor
  • Genotype
  • Glutathione Transferase / genetics
  • Mutation / genetics
  • Phenotype
  • Pigmentation / genetics
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / metabolism*
  • RNA-Dependent RNA Polymerase / metabolism*
  • Ribonuclease III / metabolism*
  • Seedlings / growth & development
  • Sugars / metabolism


  • Anthocyanins
  • Arabidopsis Proteins
  • RNA, Messenger
  • RNA, Small Interfering
  • SGS3 protein, Arabidopsis
  • Sugars
  • Carbon
  • Glutathione Transferase
  • TRANSPARENT TESTA 19 protein, Arabidopsis
  • RDR6 protein, Arabidopsis
  • RNA-Dependent RNA Polymerase
  • DCL4 protein, Arabidopsis
  • Ribonuclease III