Overexpressing Arabidopsis ABF3 increases tolerance to multiple abiotic stresses and reduces leaf size in alfalfa

Plant Physiol Biochem. 2016 Dec;109:199-208. doi: 10.1016/j.plaphy.2016.09.020. Epub 2016 Oct 1.

Abstract

Arabidopsis ABSCISIC ACID-RESPONSIVE ELEMENT-BINDING FACTOR 3 (ABF3), a bZIP transcription factor, plays an important role in regulating multiple stress responses in plants. Overexpressing AtABF3 increases tolerance to various stresses in several plant species. Alfalfa (Medicago sativa L.), one of the most important perennial forage crops worldwide, has high yields, high nutritional value, and good palatability and is widely distributed in irrigated and semi-arid regions throughout the world. However, drought and salt stress pose major constraints to alfalfa production. In this study, we developed transgenic alfalfa plants (cv. Xinjiang Daye) expressing AtABF3 under the control of the sweetpotato oxidative stress-inducible SWPA2 promoter (referred to as SAF plants) via Agrobacterium tumefaciens-mediated transformation. After drought stress treatment, we selected two transgenic lines with high expression of AtABF3, SAF5 and SAF6, for further characterization. Under normal conditions, SAF plants showed smaller leaf size compared to non-transgenic (NT) plants, while no other morphological changes were observed. Moreover, SAF plants exhibited enhanced drought stress tolerance and better growth under drought stress treatment, which was accompanied by a reduced transpiration rate and lower reactive oxygen species contents. In addition, SAF plants showed an increased tolerance to salt and oxidative stress. Therefore, these transgenic AtABF3 alfalfa plants might be useful for breeding forage crops with enhanced tolerance to environmental stress for use in sustainable agriculture on marginal lands.

Keywords: Alfalfa; AtABF3; Drought stress; Oxidative stress salt stress; SWAP2 promoter.

MeSH terms

  • Acclimatization / genetics
  • Animal Feed
  • Arabidopsis / genetics*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / physiology*
  • Basic-Leucine Zipper Transcription Factors / genetics*
  • Basic-Leucine Zipper Transcription Factors / physiology*
  • Chlorophyll / metabolism
  • Droughts
  • Genes, Plant
  • Malondialdehyde / metabolism
  • Medicago sativa / genetics*
  • Medicago sativa / growth & development
  • Medicago sativa / physiology*
  • Oxidative Stress
  • Peroxidases / genetics
  • Plant Leaves / growth & development
  • Plant Proteins / genetics
  • Plants, Genetically Modified
  • Promoter Regions, Genetic
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Stress, Physiological / genetics
  • Up-Regulation
  • Water / metabolism

Substances

  • ABF3 protein, Arabidopsis
  • Arabidopsis Proteins
  • Basic-Leucine Zipper Transcription Factors
  • Plant Proteins
  • Recombinant Proteins
  • Water
  • Chlorophyll
  • Malondialdehyde
  • Peroxidases
  • swpa2 protein, Ipomoea batatas