Detection of Arabinogalactan-protein-and extensin-like in coconut (Cocos nucifera L.)seednuts and seedlings at different stages of development

The presence of arabinogalactan protein (AGP) and extensin have been shown to play important roles in cell differentiation and plant development. Studies of these proteins in coconut are expected to help identify the genes involved in embryo maturation and germination. They were determined in coconut seednuts and seedlings at different stages of development using SDS-PAGE and immunoassay. Attempts were also made to isolate and characterize the genes encoding or AGP and extensin. Based on Bradford assay,the protein contents of different ages of embryo and solid endosperm ranged from 17.86-24.26 and 31.26-43.72 ug/mg sample, respectively; those of the haustorium and defatted solid endosperm ranged from 6.64-31/82 and 25.94-32.39 ug/mg sample, respectively. The total salt soluble protein profile in SDS-PAGE showed presence of tissue-specific polypeptide bonds among the embryo, haustorium and solid endosperm, with some bonds being constitutively expressed throughout the development. Immunoassay showed that monoclonal antibodies, JIM4, JIM3 and LM2 against AGP and JIM11 and JIM12 against extensin recognized the carbohydrates epitopes and extensin, respectively, in the embryo and haustorium. These indicated the presence of AGP and extensin inthese organs. The total RNAs were isolated from embryos of different ages using Qiagen RNeasy Mini kit. Using degenerate and specific primers for AGP and extensin, respectively, RT-PCR of the total RNA and yielded DNA fragments. Identities of AGPs and extensins based on the partial cDNA sequence were not established due to lack of sequence homology. Immunoassay and silico that were pudative extensin-like and AGP-like proteins whose specific functions need further validation. Identification of specific motifs that are involved in regulation and signal transduction processes indicates that these proteins possess specific biological activities.