A putative BABY BOOM-like gene (CaBBM) is expressed in embryogenic calli and embryogenic cell suspension culture of Coffea arabica L

Abstract

The acquisition of embryogenic cell suspension (ECS) cultures has been one of the main objectives to maximize clonal propagation of the coffee plant. However, the majority of somatic embryogenesis induction requirements are genotype-dependent. Therefore, molecular markers linked to the embryogenic transition events may be useful. The BABY BOOM (BBM) gene can be considered as one of those markers, as it is related to the embryogenic process and to cell proliferation. BBM homologous sequences were obtained from Expressed Sequence Tags (ESTs) in a databank generated by the Brazilian Coffee Genome Project. We selected EST-contigs that showed similarities with BBM sequence from different species. Two EST-contigs (C2 and C9) were expressed in silico in cellular suspension libraries and embryogenic calli of coffee. Contig C9, defined as BBM-like (CaBBM), presented similarity with BBM genes and showed 2-fold change in expression in ECS relative to embryogenic calli (EC). Contig C2, on the other hand, was related to the ERF-like family. It showed basal expression in non-embryogenic calli (NEC) and approximately 66- and 311-fold less in ECS and EC compared with CaBBM in the same samples, respectively. These data suggest that CaBBM is likely to be a BBM ortholog in Coffea arabica, which has potential for use as a molecular marker to further increase the methodological efficiency of in vitro culture of coffee.