title: The oil palm SHELL gene controls oil yield and encodes a homologue of SEEDSTICK.
abstract: A key event in the domestication and breeding of the oil palm Elaeis guineensis was loss of the thick coconut-like shell surrounding the kernel. Modern E. guineensis has three fruit forms, dura (thick-shelled), pisifera (shell-less) and tenera (thin-shelled), a hybrid between dura and pisifera. The pisifera palm is usually female-sterile. The tenera palm yields far more oil than dura, and is the basis for commercial palm oil production in all of southeast Asia. Here we describe the mapping and identification of the SHELL gene responsible for the different fruit forms. Using homozygosity mapping by sequencing, we found two independent mutations in the DNA-binding domain of a homologue of the MADS-box gene SEEDSTICK (STK, also known as AGAMOUS-LIKE 11), which controls ovule identity and seed development in Arabidopsis. The SHELL gene is responsible for the tenera phenotype in both cultivated and wild palms from sub-Saharan Africa, and our findings provide a genetic explanation for the single gene hybrid vigour (or heterosis) attributed to SHELL, via heterodimerization. This gene mutation explains the single most important economic trait in oil palm, and has implications for the competing interests of global edible oil production, biofuels and rainforest conservation.
authors.affiliation: Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia. raviga@mpob.gov.my
authors.forename: Rajinder
authors.initials: R
authors.lastname: Singh
authors.forename: Eng-Ti Leslie
authors.initials: ET
authors.lastname: Low
authors.forename: Leslie Cheng-Li
authors.initials: LC
authors.lastname: Ooi
authors.forename: Meilina
authors.initials: M
authors.lastname: Ong-Abdullah
authors.forename: Ngoot-Chin
authors.initials: NC
authors.lastname: Ting
authors.forename: Jayanthi
authors.initials: J
authors.lastname: Nagappan
authors.forename: Rajanaidu
authors.initials: R
authors.lastname: Nookiah
authors.forename: Mohd Din
authors.initials: MD
authors.lastname: Amiruddin
authors.forename: Rozana
authors.initials: R
authors.lastname: Rosli
authors.forename: Mohamad Arif Abdul
authors.initials: MA
authors.lastname: Manaf
authors.forename: Kuang-Lim
authors.initials: KL
authors.lastname: Chan
authors.forename: Mohd Amin
authors.initials: MA
authors.lastname: Halim
authors.forename: Norazah
authors.initials: N
authors.lastname: Azizi
authors.forename: Nathan
authors.initials: N
authors.lastname: Lakey
authors.forename: Steven W
authors.initials: SW
authors.lastname: Smith
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Budiman
authors.forename: Michael
authors.initials: M
authors.lastname: Hogan
authors.forename: Blaire
authors.initials: B
authors.lastname: Bacher
authors.forename: Andrew
authors.initials: A
authors.lastname: Van Brunt
authors.forename: Chunyan
authors.initials: C
authors.lastname: Wang
authors.forename: Jared M
authors.initials: JM
authors.lastname: Ordway
authors.forename: Ravigadevi
authors.initials: R
authors.lastname: Sambanthamurthi
authors.forename: Robert A
authors.initials: RA
authors.lastname: Martienssen
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics; D028023:Arecaceae / Q000235:genetics* / Q000378:metabolism*; D002874:Chromosome Mapping; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D014644:Genetic Variation; D006720:Homozygote; D026161:MADS Domain Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D000073878:Palm Oil; D010938:Plant Oils; D016415:Sequence Alignment
chemical_list: D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; D010938:Plant Oils; C476012:SEEDSTICK protein, Arabidopsis; D000073878:Palm Oil