Cloning and Characterization of the Leafy Cotyledon1 (LEC1) Gene in Oil Palm (Elaeis guineensis Jacq.), a Regulator of Somatic Embryogenesis

Oil palm (Elaeis guineensis Jacq.) is one of the most important oil-bearing crops in the world. The vegetative propagation of the oil palm to meet the high demand is required by a tissue culture technique. Unfortunately, the oil palm tissue culture takes at least one and a half year from the beginning to the generation of small plantlets. The somatic embryogenesis stage is the longest stage in the oil palm tissue culture, usually 7-8 months. A LEAFY COTYLEDON1 (LEC1) gene was shown to be a key regulator of plant somatic embryogenesis. Cloning of oil palm LEC1 gene may help to understand this mechanism in oil palm. The LEC1 gene was isolated from the oil palm tissue culture and studied its expression level using qPCR. The results showed that the EgLEC1 gene was expressed at the highest level in globular and plantlet stages. The EgLEC1 gene contains an open reading frame of 651 bp and encodes 216 amino acid residuals, which contains a B domain of HAP3 subunit. Genetic relationship based on the LEC1 gene sequence revealed that the EgLEC1 gene was closely related to a homologue in Zea mays and Oryza sativa. Ectopic expression of the EgLEC1 gene in Arabidopsis lec1-1 mutants has shorter diameter of rosette leave and plant height than the lec1-1 mutant, but similar to wild type. Flower length was similar to the lec1-1 mutant, but shorter than wild type. The results from our finding suggested that the EgLEC1 gene involves in the regulation of the somatic embryogenesis in oil palm. The detail characterization of the EgLEC1 gene will be beneficial to the oil palm breeders in shortening the tissue culture process.