The oil palm Shell gene controls oil yield and encodes a homologue of SEEDSTICK

Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia.
Nature (Impact Factor: 41.46). 07/2013; 500(7462). DOI: 10.1038/nature12356
Source: PubMed


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.

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    • "It was also located on the same p5-sc00064 scaffold of the p5-build and chromosome 3, which strongly suggests that both the genes are identical. The recent release of the oil palm genome sequence provides rapid means to identify genes of interest from oil palm (Singh et al. 2013). The preliminary search identified putative members of the lipase class 3 family in oil palm with identities ranging from 26 to 83 % to FLL1. "
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    ABSTRACT: Lipase class 3 is part of the triacylglycerol lipase family involved in lipid degradation, esterification, and transesterification processes in plants. In this study, a lipase class 3 gene and promoter from the oil palm (Elaeis guineensis Jacq.) was isolated and characterized by Northern blot, Southern blot, oil palm genome sequence, and transient expression GUS assay. The full-length lipase class 3 (FLL1) deduced polypeptide encoded 483 amino acids and was identical to that deduced from lipase (EgLip1) cDNA (GI: 409994625). It contained the lipase consensus sequence, GxSxG motif, and putative catalytic triad and had a 3-dimensional protein model similar to that of a lipase from Giberella zeae with 50 % identity. The Northern blot and reverse transcription polymerase chain reaction (RT-PCR) showed that FLL1 was predominantly expressed in the mesocarp and the expression increased as fruits reached maturity. A lower expression was detected in germinated seedlings and especially in roots. The expression of FLL1 was also enhanced in the mesocarp of cold treated fruits. A high oil accumulation in the mesocarp during fruit development makes this tissue a suitable target for a genetic modification, hence the isolation of the FLL1 promoter. The transient expression of the β-glucuronidase (GUS) gene driven by the FLL1 promoter detected the GUS expression in mesocarp slices, especially in vascular bundles. This suggests the potential role of using the promoter as tool to direct the expression of a transgene to the mesocarp of transgenic oil palm.
    No preview · Article · Jun 2015 · Biologia Plantarum
    • "Alternatively , we could change the formation of the endocarp cells that eventually lignify either by eliminating them like in the stoneless mutant of Mr. Burbank or changing them into mesocarp cells. This also has precedence in the literature because there is a natural mutation in oil palms that has no endocarp layer of cells as a result of the absence of a functional transcription factor SEEDSTICK (Singh et al., 2013). When one copy of the gene is present, a thin endocarp is formed and when two copies are present, a normal hardened endocarp is present. "
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    ABSTRACT: The theme running through many of Luther Burbank’s breeding programs was to make plants more tailored to human uses. Mr. Burbank thought that the stone in plum fruits was unessential to a tree that was propagated vegetatively, so he chose stoneless plums as a breeding goal. He made two releases, ‘Miracle’ in 1903 and his final and almost perfect ‘Conquest’ in 1916, which he considered one of his best accomplishments in plum breeding. ‘Conquest’ had only a grain of stone and flavor and size comparable to the best French types of the time but was not commercially successful. In view of the current desire for convenience food such as seedless fruit (citrus, grapes, watermelon) and advanced knowledge of genetics and breeding technologies, we have taken up where Mr. Burbank left off in the production of a better than “almost perfect” stoneless plum. We began by locating what were most likely remnants from Mr. Burbank’s breeding program and we are now using 21st century technology to achieve a completely stoneless, high-quality plum fruit. These technologies include molecular markers, genetic engineering, and accelerated breeding cycles (FasTrack). Initial experiments had characterized the stoneless trait as a decrease in the number of endocarp cells that form the stone. We defined the time critical to the formation of endocarp by analyzing gene expression of a number of transcription factors involved with determining endocarp cells. We identified genes that were expressed differently during this period between normal stone cultivars and one of the stoneless cultivars. In addition, we targeted genes for genetic engineering to reduce the lignification in endocarp and to reduce or convert endocarp cells to non-lignifying cells. A system, FasTrack, using a flowering gene from poplar, has been incorporated to reduce the juvenility period and eliminate the seasonal aspect of fruiting to see the results of the breeding as well as the genetic engineering approach much faster. The combination of these approaches is now in place to attempt to improve on Mr. Burbank’s stoneless plum.
    No preview · Article · Feb 2015 · HortScience: a publication of the American Society for Horticultural Science
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    • "Further improvements in yield could potentially be made through genetic modification (e.g. recent work by Singh et al. (2013) on mapping the oil palm genome identified a gene that regulates oil yield) or through improved efficiency and management (Carter et al., 2007). Average yield for oil palm is around 4 t crude palm oil ha -1 in Indonesia and Malaysia (Corley, 2009). "
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    ABSTRACT: Increasing the yield of existing oil palm plantations is one means of accommodating some of the growing demand for palm oil. The International Plant Nutrition Institute (IPNI) has developed and tested a process to deploy a series of ‘best management practices’ (BMPs) that cover a range of agronomic practices intended to intensify oil palm production and improve yield at a given site using cost-effective, practical methods. Many of these BMPs include techniques that should also improve soil quality, such as the addition of organic matter to the soil surface, and improved timing and tailored application of mineral and organic fertilisers. Six plantations in Kalimantan and Sumatra applied BMPs prescribed by IPNI (BMP treatment), and standard management practices (REF treatment) in paired blocks of oil palm over four years; 30 pairs of blocks were included in the research. Soils were sampled in both treatments before and after the field trial, from beneath weeded circles surrounding individual palms and beneath frond piles in between rows of palms, at 0–20 cm depth and 20–40 cm depth. Soils were tested for a range of properties, including soil pH, % soil organic carbon (% SOC), total N, available P, and exchangeable cations. No clear, consistent differences were found in the degree of change in soil properties between BMP and REF treatments over four years. However, improvements in some soil properties were noted for both treatments, particularly for soil pH and % SOC. There was no significant deterioration in the measured soil properties over the four years. The results suggest that appropriate management practices for oil palm can improve several aspects of soil quality. Further research on the mechanisms by which BMPs can improve soil quality, and monitoring over longer periods of time is recommended to give plantation managers a clearer picture of the potential ‘co-benefits’ that can be obtained with adoption of BMPs designed to increase oil palm yield.
    Full-text · Article · Oct 2014 · Agriculture Ecosystems & Environment
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