title: Differential proteomic analysis of embryogenic lines in oil palm (Elaeis guineensis Jacq).
abstract: Oil palm tissue culture is one way to produce superior oil palm planting materials. However, the low rate of embryogenesis is a major hindrance for the adoption of this technology in oil palm tissue culture laboratories. In this study, we use proteomic technologies to compare differential protein profiles in leaves from palms of high and low proliferation rates in tissue culture in order to understand the underlying biological mechanism for the low level of embryogenesis. Two protein extraction methods, namely trichloroacetic acid/acetone precipitation and polyethylene glycol fractionation were used to produce total proteins and fractionated protein extracts respectively, with the aim of improving the resolution of protein species using two-dimensional gel electrophoresis. A total of 40 distinct differential abundant protein spots were selected from leaf samples collected from palms with proven high and low proliferation rates. The variant proteins were subsequently identified using mass spectrometric analysis. Twelve prominent protein spots were then characterised using real-time polymerase chain reaction to compare the mRNA expression and protein abundant profiles. Three proteins, namely triosephosphate isomerase, l-ascorbate peroxidase, and superoxide dismutase were identified to be potential biomarker candidates at both the protein abundant and mRNA expression levels.
  
  
  
  In this study, proteomic analysis was used to identify abundant proteins from total protein extracts. PEG fractionation was used to reveal lower abundant proteins from both high and low proliferation embryogenic lines of oil palm samples in tissue culture. A total of 40 protein spots were found to be significant in abundance and the mRNA levels of 12 of these were assessed using real time PCR. Three proteins namely, triosephosphate isomerase, l-ascorbate peroxidase and superoxide dismutase were found to be concordant in their mRNA expression and protein abundance. Triosephosphate isomerase is a key enzyme in glycolysis. Both l-ascorbate peroxidase and superoxide dismutase play a role in anti-oxidative scavenging defense systems. These proteins have potential for use as biomarkers to screen for high and low embryogenic oil palm samples.
authors.affiliation: School of Biosciences, Faculty of Science, University of Nottingham, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: Hooi Sin
authors.initials: HS
authors.lastname: Tan
authors.affiliation: School of Biosciences, Faculty of Science, University of Nottingham, United Kingdom.
authors.forename: Susan
authors.initials: S
authors.lastname: Liddell
authors.affiliation: Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia.
authors.forename: Meilina
authors.initials: M
authors.lastname: Ong Abdullah
authors.affiliation: Advanced Agriecological Research Sdn Bhd, No. 11 Jalan Teknologi 3/6, Taman Sains Selangor 1, Kota Damansara, 47810 Petaling Jaya, Selangor, Malaysia; AAR-UNMC Biotechnology Research Centre, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: Wei Chee
authors.initials: WC
authors.lastname: Wong
authors.affiliation: School of Biosciences, Faculty of Science, University of Nottingham, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: Chiew Foan
authors.initials: CF
authors.lastname: Chin
mesh_terms: D028023:Arecaceae / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development; D060387:Ascorbate Peroxidases / Q000032:analysis / Q000235:genetics; D015415:Biomarkers; D049109:Cell Proliferation; D018515:Plant Leaves / Q000737:chemistry*; D010940:Plant Proteins / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D018749:RNA, Plant / Q000032:analysis*; D013482:Superoxide Dismutase / Q000032:analysis / Q000235:genetics; D014305:Triose-Phosphate Isomerase / Q000032:analysis / Q000235:genetics
chemical_list: D015415:Biomarkers; D010940:Plant Proteins; D018749:RNA, Plant; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase; D014305:Triose-Phosphate Isomerase
keywords: Elaeis guineensis; Embryogenic lines; Leaf explant; Polyethylene glycol; Proliferation rate; Protein expression