TcLEC2 Gene May Aid in Somatic Embryogenesis of Cacao

In vitro somatic embryogenesis (SE) tissue culture is an approach able to speed up the development and deployment of plants due to its potentially high multiplication rate and scalability. This is the new approach considered in the propagation of the cacao tree (Theobroma cacao L.). Cacao is a highly heterozygous crop and requires vegetative propagation through grafting and rooted cuttings to multiply. Though somatic embryogenesis is promising for cacao, it can also be limited by embryogenic efficiency, which varies significantly between genotypes.

An ortholog of the Arabidopsis' AtLEC2 gene was also found in cacao, the TcLEC2 gene. It codes for a B3 domain transcription factor expressed during zygotic embryo development. TcLEC2 expression was found to be higher in dedifferentiated cells or embryonic calli. The overexpression of TcLEC2 in cacao explants greatly increased the regeneration of stably transformed somatic embryos while cotyledon explants overexpressing TcLEC2 exhibited a very high level of embryogenic competency.

The study discovered the essential roles of TcLEC2 during both zygotic and somatic embryo development. TcLEC2 could potentially be used as a biomarker for the improvement of the SE process and screen for elite varieties in cacao germplasm.

For more information on the study, visit http://www.biomedcentral.com/1471-2229/14/106/abstract.