Virtual screening and in vitro evaluation of potential growth regulators against somatic embryogenesis receptor-like kinase (SERK) in Cocos nucifera L.

Coconut (Cocos nucifera L.) is one of the most recalcitrant species for in vitro regeneration and the efficiency of induction of somatic embryogenesis in coconut explants has remained low. However, with the advent of the genomics era, more information is now available on the involvement of many genes in the induction of somatic embryogenic pathway. Somatic embryogenesis receptor-like kinases (SERKs), belonging to leucine-rich repeat receptor-like kinase super family are reported to play important roles in the process of somatic embryogenesis. In this study, homology based modeling and molecular dynamics (MD) simulation of a coconut SERK protein (CnSERK) was performed for exploring its structural features, functional characterization of its active sites and binding mechanisms of selected plant hormones and growth regulators by docking studies. The 3-D model for coconut SERK was constructed using structure neighbors of the protein in MODELLER and MD simulation was carried out using GROMACS for 5 ns. Fifteen plant growth regulators were docked with the target SERK protein using GLIDE software. An in vitro study was then carried out to compare the efficiency of three selected chemicals [adenine sulphate, glutathione and 22(S), 23(S)-homobrassinolide] in enhancing somatic embryogenesis from plumular explants of coconut. Plumular explants were from West Coast Tall cultivar of coconut and were inoculated into Eeuwens Y3 media supplemented with various concentrations of each of the three growth regulators. Among the three growth regulators, glutathione (100 uM) gave the best response for induction of both embryogenic calli and somatic embryogenesis. The results of this study might aid in the development of regeneration protocols for in vitro regeneration in coconut