Inducible somatic embryogenesis in Theobroma cacao achieved using the DEX-activatable transcription factor-glucocorticoid receptor fusion

Biotechnol Lett. 2017 Nov;39(11):1747-1755. doi: 10.1007/s10529-017-2404-4. Epub 2017 Jul 31.


Objectives: To carry out mass propagation of superior plants to improve agricultural and silvicultural production though advancements in plant cell totipotency, or the ability of differentiated somatic plant cells to regenerate an entire plant.

Results: The first demonstration of a titratable control over somatic embryo formation in a commercially relevant plant, Theobroma cacao (Chocolate tree), was achieved using a dexamethasone activatable chimeric transcription factor. This four-fold enhancement in embryo production rate utilized a glucocorticoid receptor fused to an embryogenic transcription factor LEAFY COTYLEDON 2. Where previous T. cacao somatic embryogenesis has been restricted to dissected flower parts, this construct confers an unprecedented embryogenic potential to leaves.

Conclusions: Activatable chimeric transcription factors provide a means for elucidating the regulatory cascade associated with plant somatic embryogenesis towards improving its use for somatic regeneration of transgenics and plant propagation.

Keywords: Chimeric transcription factor; Chocolate; Glucocorticoid receptor; LEAFY COTYLEDON 2; Plant propagation; Somatic embryogenesis; Theobroma cacao.

MeSH terms

  • Cacao / drug effects
  • Cacao / embryology*
  • Dexamethasone / pharmacology*
  • Enzyme Activation
  • Gene Expression Regulation, Developmental / drug effects
  • Gene Expression Regulation, Plant / drug effects
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plant Somatic Embryogenesis Techniques
  • Plants, Genetically Modified
  • Receptors, Glucocorticoid / genetics*
  • Receptors, Glucocorticoid / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism


  • Plant Proteins
  • Receptors, Glucocorticoid
  • Recombinant Fusion Proteins
  • Transcription Factors
  • Dexamethasone