Identification of molecular markers for the recognition of tissues competent for in vitro regeneration has a considerable potential for increasing the efficiency of coconut somatic embryogenesis protocol. BABYBOOM (BBM), APETALA2/Ethylene Responsive Element Binding Protein (AP2/EREBP) family gene has shown a role during embryogenesis. To gain insight into the functions of CnANT, a BABYBOOM gene homologue of coconut was cloned under the cauliflower mosaic virus-35s promoter and the plant growth and developmental changes that occur in transgenic Arabidopsis plants were determined and compared with the data obtained for other BBM genes originated from other plant species. Construction of vectors for Arabidopsis transformation was based on pGREEN plasmid. Transformed plants were screened by spraying herbicide Harvest which contains the active ingredient gluphosinate ammonium. Five independent transgenic lines were developed. All lines showed the typical 3:1 segregation ratio suggesting that the bar genes had integrated into the Arabidopsis as a single segregating locus. In comparison to wild type plants, overexpression of CnANT resulted in pleiotropic phenotypes including compact rosettes, backward curly-leaves with serrated margins, larger flowers and smaller siliques. There were also modifications in plant growth such as delay in flowering. Similar phenotypic effects observed for CnANT along with BBM and other related genes from eudicots suggest similar biochemical targets governed by these proteins. Similarity of their expression, thus suggest that CnANT gene also has a potential to increase in vitro regeneration response.
Tropical Agricultural Research Vol. 23 (3): 249-260 (2012)