Glucocorticoid receptor-regulated TcLEC2 expression triggers somatic embryogenesis in Theobroma cacao leaf tissue

Andrew S. Fister, Lena Landherr Sheaffer, Melanie Perryman, Yufan Zhang, Mark Guiltinan, Siela Maximova

Research output: Contribution to journalArticle

Abstract

Theobroma cacao, the source of cocoa, is a crop of particular importance in many developing countries. Availability of elite planting material is a limiting factor for increasing productivity of Theobroma cacao; therefore, the development of new strategies for clonal propagation is essential to improve farmers’ incomes and to meet increasing global demand for cocoa. To develop a more efficient embryogenesis system for cacao, tissue was transformed with a transgene encoding a fusion of Leafy Cotyledon 2 (TcLEC2) to a glucocorticoid receptor domain (GR) to control nuclear localization of the protein. Upon application of the glucocorticoid dexamethasone (dex), downstream targets of LEC2 involved in seed-development were up-regulated and somatic embryos (SEs) were successfully regenerated from TcLEC2-GR transgenic flower and leaf tissue in large numbers. Immature SEs regenerated from TcLEC2-GR leaves were smaller in size than immature SEs from floral tissue, suggesting a different ontogenetic origin. Additionally, exposure of TcLEC2-GR floral explants to dex increased the number of SEs compared to floral explants from control, non-transgenic trees or from TcLEC2-GR floral explants not treated with dex. Testing different durations of exposure to dex indicated that a three-day treatment produced optimal embryo regeneration. Leaf derived SEs were successfully grown to maturity, converted into plants, and established in the greenhouse, demonstrating that these embryos are fully developmentally competent. In summary, we demonstrate that regulating TcLEC2 activity offers a powerful new strategy for optimizing somatic embryogenesis pipelines for cacao.

Original languageEnglish (US)
Article numbere0207666
JournalPloS one
Volume13
Issue number11
DOIs
StatePublished - Nov 1 2018

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Theobroma cacao
Cacao
Glucocorticoid Receptors
somatic embryos
somatic embryogenesis
Embryonic Development
dexamethasone
Embryonic Structures
Dexamethasone
Tissue
Cocoa
explants
leaves
embryo (plant)
immatures
Greenhouses
glucocorticoids
seed development
Developing countries
Glucocorticoids

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

@article{8676e3c59c84464c8b3fa4ac9fae7fa8,
title = "Glucocorticoid receptor-regulated TcLEC2 expression triggers somatic embryogenesis in Theobroma cacao leaf tissue",
abstract = "Theobroma cacao, the source of cocoa, is a crop of particular importance in many developing countries. Availability of elite planting material is a limiting factor for increasing productivity of Theobroma cacao; therefore, the development of new strategies for clonal propagation is essential to improve farmers’ incomes and to meet increasing global demand for cocoa. To develop a more efficient embryogenesis system for cacao, tissue was transformed with a transgene encoding a fusion of Leafy Cotyledon 2 (TcLEC2) to a glucocorticoid receptor domain (GR) to control nuclear localization of the protein. Upon application of the glucocorticoid dexamethasone (dex), downstream targets of LEC2 involved in seed-development were up-regulated and somatic embryos (SEs) were successfully regenerated from TcLEC2-GR transgenic flower and leaf tissue in large numbers. Immature SEs regenerated from TcLEC2-GR leaves were smaller in size than immature SEs from floral tissue, suggesting a different ontogenetic origin. Additionally, exposure of TcLEC2-GR floral explants to dex increased the number of SEs compared to floral explants from control, non-transgenic trees or from TcLEC2-GR floral explants not treated with dex. Testing different durations of exposure to dex indicated that a three-day treatment produced optimal embryo regeneration. Leaf derived SEs were successfully grown to maturity, converted into plants, and established in the greenhouse, demonstrating that these embryos are fully developmentally competent. In summary, we demonstrate that regulating TcLEC2 activity offers a powerful new strategy for optimizing somatic embryogenesis pipelines for cacao.",
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Glucocorticoid receptor-regulated TcLEC2 expression triggers somatic embryogenesis in Theobroma cacao leaf tissue. / Fister, Andrew S.; Sheaffer, Lena Landherr; Perryman, Melanie; Zhang, Yufan; Guiltinan, Mark; Maximova, Siela.

In: PloS one, Vol. 13, No. 11, e0207666, 01.11.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Glucocorticoid receptor-regulated TcLEC2 expression triggers somatic embryogenesis in Theobroma cacao leaf tissue

AU - Fister, Andrew S.

AU - Sheaffer, Lena Landherr

AU - Perryman, Melanie

AU - Zhang, Yufan

AU - Guiltinan, Mark

AU - Maximova, Siela

PY - 2018/11/1

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