In silico and in vivo analysis of ABI3 and VAL2 genes during somatic embryogenesis of Coffea arabica : competence acquisition and developmental marker genes

The employment of biotechnology-based approaches such as somatic embryogenesis has been applied to several plants including Coffea sp. Despite the economic importance of this genus, few information about the role of key regulatory genes in somatic embryogenesis in coffee is available. This work provides information about ABI3 and VAL2 genes performance by RT-qPCR during indirect somatic embryogenesis of Coffea arabica . To achieve this, bioinformatics analysis was performed to identify the genes of the B3 superfamily in the coffee genome. The cell suspensions lines presented similar histological and regeneration patterns, yielding of up to 6.6 embryos per 1 mg of embryogenic aggregates at 7 months. We have identified possible orthologs for VAL2 (Cc06g00410) and ABI3 (Cc01g17380) as well as the other members belonging to superfamily B3. The CaABI3 expression was higher in dedifferentiated competent cells for somatic embryogenesis as compared with non-embryogenic calli. Whereas the expression of VAL2 gene is more active in cotyledonary embryos and plantlets, showing its clear performance in the embryogenesis late stages. The present study suggests that CaABI3 gene could be potentially used as a biomarker for embryogenic process improvement. The good plantlets development obtained from the protocol used may be a reflection of the high expression of CaVAL2 in cotyledonary embryos and plantlets.