Project description:The oil palm fruit abnormality, mantled, is a somaclonal variant arising from tissue culture that drastically reduces yield, and has largely halted efforts to clone elite hybrids for breeding and oil production. Widely regarded as epigenetic, mantling had defied explanation, and has become an icon of unsustainability in environmentally sensitive tropical plantation crops. We identified the MANTLED gene using Epigenome Wide Association analysis of genetically identical palms from multiple clonal lineages. Hypomethylation of a LINE retrotransposon related to rice Karma, found in the intron of the homeotic gene DEFICIENS, is common to all mantled clones and is correlated with alternative splicing and loss of small RNA. DNA methylation is regained in spontaneous revertants accounting for non-Medelian inheritance of the Good Karma and Bad Karma epialleles. Thus epigenetic regulation of transposable elements results in somaclonal variation and provides a means to cull mantled nursery palms before committing limiting plantation resources to clonal propagation. DNA methylation profiling was performed using the McrBC DNA methylation dependent fractionation and microarray hybridization method as described in Lippman, Z., Gendrel, A. V., Colot, V. & Martienssen, R. Profiling DNA methylation patterns using genomic tiling microarrays. Nat Methods 2, 219-224 (2005).
Project description:Oil palm (Elaeis guineensis) is a highly productive oil crop and the most consumed vegetable oil globally due to its unique oil characteristics. Palm oil production is affected by abiotic stresses, leading to food security issues and huge economic losses. To understand the oil palm responses to different abiotic stresses at the transcriptional level, we performed RNA-Seq analyses of oil palm leaves treated with drought, high salinity, heat, cold and flood stresses compared with controls. A total of 18 libraries (three biological replicates per treatment) were generated with approximately 843 million of total clean reads after data filtering. Clean reads were mapped to the oil palm reference genome at a total mapping rate of more than 70%. The quantification of expression analysis enabled the identification of potential abiotic stress-responsive genes, co-expressed under multiple abiotic stresses and unigenes that were induced by a specific abiotic stress. The availability of these RNA-Seq datasets will provide a better understanding of the abiotic stress response mechanisms to develop climate-resilient oil palm planting materials.
Project description:The oil palm fruit abnormality, mantled, is a somaclonal variant arising from tissue culture that drastically reduces yield, and has largely halted efforts to clone elite hybrids for breeding and oil production. Widely regarded as epigenetic, mantling had defied explanation, and has become an icon of unsustainability in environmentally sensitive tropical plantation crops. We identified the MANTLED gene using Epigenome Wide Association analysis of genetically identical palms from multiple clonal lineages. Hypomethylation of a LINE retrotransposon related to rice Karma, found in the intron of the homeotic gene DEFICIENS, is common to all mantled clones and is correlated with alternative splicing and loss of small RNA. DNA methylation is regained in spontaneous revertants accounting for non-Medelian inheritance of the Good Karma and Bad Karma epialleles. Thus epigenetic regulation of transposable elements results in somaclonal variation and provides a means to cull mantled nursery palms before committing limiting plantation resources to clonal propagation. DNA methylation profiling was performed using the McrBC DNA methylation dependent fractionation and microarray hybridization method as described in Lippman, Z., Gendrel, A. V., Colot, V. & Martienssen, R. Profiling DNA methylation patterns using genomic tiling microarrays. Nat Methods 2, 219-224 (2005). DNA methylation profiling was performed on 54 parthenocarpic mantled ramet, 43 normal ramet and 1 ortet adult leaf samples. For each sample, two independent fractionations of total genomic DNA and DNA methylation-depleted DNA were performed. Each total DNA/methylation-depleted DNA pair was differentially labeled and hydrized to a custon Nimblegen microarray in a dye-swapped design (4 array hybridizations per sample).