title: Fine-mapping and cross-validation of QTLs linked to fatty acid composition in multiple independent interspecific crosses of oil palm.
abstract: BACKGROUND
  The commercial oil palm (Elaeis guineensis Jacq.) produces a mesocarp oil (commonly called 'palm oil') with approximately equal proportions of saturated and unsaturated fatty acids (FAs). An increase in unsaturated FAs content or iodine value (IV) as a measure of the degree of unsaturation would help to open up new markets for the oil. One way to manipulate the fatty acid composition (FAC) in palm oil is through introgression of favourable alleles from the American oil palm, E. oleifera, which has a more unsaturated oil.
  
  
  RESULTS
  In this study, a segregating E. oleifera x E. guineensis (OxG) hybrid population for FAC is used to identify quantitative trait loci (QTLs) linked to IV and various FAs. QTL analysis revealed 10 major and two putative QTLs for IV and six FAs, C14:0, C16:0, C16:1, C18:0, C18:1 and C18:2 distributed across six linkage groups (LGs), OT1, T2, T3, OT4, OT6 and T9. The major QTLs for IV and C16:0 on LGOT1 explained 60.0 - 69.0 % of the phenotypic trait variation and were validated in two independent BC2 populations. The genomic interval contains several key structural genes in the FA and oil biosynthesis pathways such as PATE/FATB, HIBCH, BASS2, LACS4 and DGAT1 and also a relevant transcription factor (TF), WRI1. The literature suggests that some of these genes can exhibit pleiotropic effects in the regulatory networks of these traits. Using the whole genome sequence data, markers tightly linked to the candidate genes were also developed. Clustering trait values according to the allelic forms of these candidate markers revealed significant differences in the IV and FAs of the palms in the mapping and validation crosses.
  
  
  CONCLUSIONS
  The candidate gene approach described and exploited here is useful to identify the potential causal genes linked to FAC and can be adopted for marker-assisted selection (MAS) in oil palm.
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.|School of Biosciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor, Malaysia.
authors.forename: Ngoot-Chin
authors.initials: NC
authors.lastname: Ting
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Zulkifli
authors.initials: Z
authors.lastname: Yaakub
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Katialisa
authors.initials: K
authors.lastname: Kamaruddin
authors.affiliation: Plant and Crop Sciences, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD, UK.
authors.forename: Sean
authors.initials: S
authors.lastname: Mayes
authors.affiliation: School of Biosciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor, Malaysia.
authors.forename: Festo
authors.initials: F
authors.lastname: Massawe
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Ravigadevi
authors.initials: R
authors.lastname: Sambanthamurthi
authors.affiliation: Biometris, Wageningen University and Research Centre, P.O. Box 100, 6700 AC, Wageningen, The Netherlands.
authors.forename: Johannes
authors.initials: J
authors.lastname: Jansen
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Leslie Eng Ti
authors.initials: LE
authors.lastname: Low
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Maizura
authors.initials: M
authors.lastname: Ithnin
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Kushairi
authors.affiliation: United Plantations Bhd., Jendarata Estate, 36009, Teluk Intan, Perak, Malaysia.
authors.forename: Xaviar
authors.initials: X
authors.lastname: Arulandoo
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Rozana
authors.initials: R
authors.lastname: Rosli
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Kuang-Lim
authors.initials: KL
authors.lastname: Chan
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Nadzirah
authors.initials: N
authors.lastname: Amiruddin
authors.affiliation: United Plantations Bhd., Jendarata Estate, 36009, Teluk Intan, Perak, Malaysia.
authors.forename: Kandha
authors.initials: K
authors.lastname: Sritharan
authors.affiliation: United Plantations Bhd., Jendarata Estate, 36009, Teluk Intan, Perak, Malaysia.
authors.forename: Chin Ching
authors.initials: CC
authors.lastname: Lim
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Rajanaidu
authors.initials: R
authors.lastname: Nookiah
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia.
authors.forename: Mohd Din
authors.initials: MD
authors.lastname: Amiruddin
authors.affiliation: Malaysian Palm Oil Board (MPOB), P.O. Box 10620, 50720, Kuala Lumpur, Malaysia. rajinder@mpob.gov.my.
authors.forename: Rajinder
authors.initials: R
authors.lastname: Singh
mesh_terms: D028023:Arecaceae / Q000737:chemistry / Q000235:genetics*; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D018744:DNA, Plant / Q000235:genetics; D005227:Fatty Acids / Q000737:chemistry*; D017343:Genes, Plant; D005819:Genetic Markers; D018895:Microsatellite Repeats; D000073878:Palm Oil; D010641:Phenotype; D010938:Plant Oils / Q000737:chemistry; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant; D005227:Fatty Acids; D005819:Genetic Markers; D010938:Plant Oils; D000073878:Palm Oil
keywords: Backcross-two (BC2); Elaeis guineensis; Elaeis oleifera; Iodine value (IV); Oleic acid (C18:1); Palmitic acid (C16:0)