The sunflower transcription factor HaHB11 confers tolerance to water deficit and salinity to transgenic Arabidopsis and alfalfa plants

J Biotechnol. 2017 Sep 10:257:35-46. doi: 10.1016/j.jbiotec.2016.11.017. Epub 2016 Nov 22.

Abstract

Homeodomain-leucine zipper (HD-Zip) transcription factors are unique to the plant kingdom; members of subfamily I are known to be involved in abiotic stress responses. HaHB11 belongs to this subfamily and it was previously shown that it is able to confer improved yield and tolerance to flooding via a quiescent strategy. Here we show that HaHB11 expression is induced by ABA, NaCl and water deficit in sunflower seedlings and leaves. Arabidopsis transgenic plants expressing HaHB11, controlled either by its own promoter or by the constitutive 35S CaMV, presented rolled leaves and longer roots than WT when grown under standard conditions. In addition, these plants showed wider stems and more vascular bundles. To deal with drought, HaHB11 transgenic plants closed their stomata faster and lost less water than controls, triggering an enhanced tolerance to such stress condition and also to salinity stress. Concomitantly, ABA-synthesis and sensing related genes were differentially regulated in HaHB11 transgenic plants. Either under long-term salinity stress or mild drought stress, HaHB11 transgenic plants did not exhibit yield penalties. Moreover, alfalfa transgenic plants were generated which also showed enhanced drought tolerance. Altogether, the results indicated that HaHB11 was able to confer drought and salinity tolerance via a complex mechanism which involves morphological, physiological and molecular changes.

Keywords: Drought tolerance; HaHB11; Homeodomain-leucine zipper I; Seed yield; Transcription factor; Vascular bundles.

MeSH terms

  • Adaptation, Biological / genetics
  • Adaptation, Biological / physiology
  • Adaptation, Physiological / genetics
  • Adaptation, Physiological / physiology
  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Biomass
  • Droughts*
  • Gene Expression Regulation, Plant / genetics
  • Gene Expression Regulation, Plant / physiology
  • Helianthus / genetics*
  • Homeodomain Proteins / chemistry
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Leucine Zippers / genetics
  • Medicago sativa / genetics
  • Medicago sativa / metabolism
  • Medicago sativa / physiology*
  • Plant Leaves / metabolism
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism
  • Plants, Genetically Modified / physiology*
  • Promoter Regions, Genetic
  • Salt Tolerance / physiology*
  • Seedlings
  • Stress, Physiological / genetics
  • Stress, Physiological / physiology
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Water

Substances

  • Arabidopsis Proteins
  • HAHR1 protein, plant
  • Homeodomain Proteins
  • Plant Proteins
  • Transcription Factors
  • Water