A novel ABA-insensitive mutant in Arabidopsis reveals molecular network of ABA-induced anthocyanin accumulation and abiotic stress tolerance

J Plant Physiol. 2022 Nov;278:153810. doi: 10.1016/j.jplph.2022.153810. Epub 2022 Sep 12.

Abstract

Abscisic acid (ABA) plays primary regulatory roles in abiotic stress tolerance and seed germination. Here, we report a unique novel Arabidopsis abscisic acid-insensitive mutant, abr (abscisic acid resistance), which was able to germinate in medium containing high ABA concentrations and tolerant to abiotic stress tolerance. We observed that abr mutant accumulated more anthocyanins by ABA treatment than did the wild type (WT). Dimethylthiourea (DMTU, an H2O2 scavenger) was effective in inhibiting ABA-induced anthocyanins accumulation. RNA-seq showed that the expression of anthocyanins synthesis, antioxidant enzyme and stress-related genes were specifically increased in ABA-treated abr seedlings, suggesting that the abr mutation affects stress response as well as ABA responses. Interestingly, seedlings accumulating anthocyanins exhibited more tolerance to mannitol and NaCl compared to wild type. We propose that ABA-induced H2O2 generation triggers the foliar anthocyanins accumulation, which, in turn, enhances the abiotic stress tolerance in abr mutant.

Keywords: ABA; ABA-Insensitive mutant; Abiotic stress; Anthocyanin; H(2)O(2).

MeSH terms

  • Abscisic Acid / metabolism
  • Abscisic Acid / pharmacology
  • Anthocyanins / metabolism
  • Antioxidants / metabolism
  • Arabidopsis Proteins* / metabolism
  • Arabidopsis* / metabolism
  • Gene Expression Regulation, Plant
  • Germination
  • Hydrogen Peroxide / metabolism
  • Mannitol / pharmacology
  • Mutation / genetics
  • Seedlings / metabolism
  • Sodium Chloride / pharmacology
  • Stress, Physiological / genetics

Substances

  • Anthocyanins
  • Antioxidants
  • Arabidopsis Proteins
  • Mannitol
  • Sodium Chloride
  • Abscisic Acid
  • Hydrogen Peroxide