PKS-A Clade of Oil Palm Might Play Role During Defense Against Ganoderma boninense Infection

ABSTRACTSPolyketide synthase (PKS) is an essential catalyzing enzyme in the polyketide (PK) biosynthesis pathway of bacteria, fungi and plants which have diverse beneficial functions such as antibiotic and antiparasitic. This study was aimed to identify specific plant type III PKSs in the African oil palm, Elaeis guineensis, and predict its biosynthesized metabolites as plant defense compounds against the most threatening fungal pathogen, Ganoderma boninense that causing the basal stem rot disease. We used the oil palm protein database to detect the presence of type III PKS domains using the HMMER version V3.1b2. An artificial inoculation was made on oil palm root tissues and RNA sequencing was performed to obtain the transcriptome profile after 7 days exposure to G. boninense. Among 40,421 proteins, we identified 38 of which containing type III PKS domains. Signal peptide signature motifs were absence in all PKSs suggesting their intracellular functions during the polyketide biosynthesis. A molecular phylogeny analysis reflected the relationships among these PKSs that clustered into PKS-A, -B and -C clades. Most of the PKS-A members were up-regulated after G. boninense infection, indicating their essential role in the biosynthesis of PK products which might needed for defense.