Plant Cell, Tissue and Organ Culture (PCTOC)

, Volume 102, Issue 3, pp 285–295

Somatic embryogenesis and plant regeneration of tropical maize genotypes

  • Sylvester Elikana Anami
  • Allan Jalemba Mgutu
  • Catherine Taracha
  • Griet Coussens
  • Mansour Karimi
  • Pierre Hilson
  • Mieke Van Lijsebettens
  • Jesse Machuka
Original Paper

DOI: 10.1007/s11240-010-9731-7

Cite this article as:
Anami, S.E., Mgutu, A.J., Taracha, C. et al. Plant Cell Tiss Organ Cult (2010) 102: 285. doi:10.1007/s11240-010-9731-7

Abstract

In Latin America and sub-Saharan Africa, tropical maize (Zea mays L.) is a major crop for human consumption. To cope with the increasing population and changing environment, there is a need for improving tropical maize germplasm. As part of a biotechnological approach, efficient in vitro regeneration of two tropical maize inbred lines (CML216 and CML244) was established. A number of parameters were optimized, such as age of the immature embryos, plant media and growth regulator concentration. After 6 weeks of culture, somatic embryos that had already reached the coleoptilar stage produced shoots after light induction and developed into fertile plants after acclimation in the soil. The callus induction frequencies and somatic embryo-derived plantlet formation were higher when cultured with the Linsmaier and Skoog medium than those with the Chu’s N6 basal medium. Regeneration of tropical maize shoots depended on the 2,4-dichlorophenoxyacetic acid (2,4-D) concentration at the callus initiation stage from immature embryos. The recalcitrance of the tropical maize inbred line TL26 to in vitro regeneration was overcome in a single-cross hybrid with the CML216 and CML244 genotypes. Remarkably, tropical maize somatic embryos were formed at the abaxial side of the scutellum facing the medium, probably from the axis of the immature embryos, as shown by histological sections. Upon co-cultivation, agrobacteria transiently expressed their intronless β-glucuronidase-encoding gene at the embryogenic tissue, but not with an intron-containing gene, suggesting that virulence genes are induced in Agrobacterium, but that subsequent steps in the T-DNA transfer are inhibited.

Keywords

Tropical maizeCallus inductionSomatic embryogenesis

Abbreviations

2,4-D

2,4-Dichlorophenoxyacetic acid

bar

Phosphinothricin acetyltransferase-encoding gene

CIM

Callus induction medium or resting medium

CMM

Callus maturation medium

ESM/Inf

Embryo suspension medium/infection medium

GUS

β-glucuronidase

LS

Linsmaier and Skoog

MES

2-(N-morpholino)ethanesulphonic acid

MS

Murashige and Skoog

N6

Chu’s N6 basal medium

P35

Cauliflower mosaic virus 35S promoter

PIPES

Piperazine-N,N-bis(2-ethanesulphonic acid)

R0

Regenerated shoot from somatic embryo

R1

Progeny of R0 shoot

SIM

Shoot induction medium or regeneration medium

T-DNA

Transfer DNA

T35S

Cauliflower mosaic virus 35S terminator

Tnos

Nopaline synthase terminator

UBIL

Maize long ubiquitin promoter

uidA

β-d-glucuronidase gene from Escherichia coli

X-Gluc

5-Bromo-4-chloro-3-indolyl-β-d-glucuronic acid

YEP

Yeast Extract Peptone

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Sylvester Elikana Anami
    • 1
    • 2
    • 3
  • Allan Jalemba Mgutu
    • 1
  • Catherine Taracha
    • 4
  • Griet Coussens
    • 2
    • 3
  • Mansour Karimi
    • 2
    • 3
  • Pierre Hilson
    • 2
    • 3
  • Mieke Van Lijsebettens
    • 2
    • 3
  • Jesse Machuka
    • 1
  1. 1.Plant Transformation Facility, Department of Biochemistry and BiotechnologyKenyatta UniversityNairobiKenya
  2. 2.Department of Plant Systems BiologyVIBGentBelgium
  3. 3.Department of Plant Biotechnology and GeneticsGhent UniversityGentBelgium
  4. 4.Kenya Agricultural Research InstituteNairobiKenya