Section: New Results

Elaeis guineensis transcriptome

The mesocarp of the oil palm tree (Elaeis guineensis Jacq.) contains oil up to 90% of its dry weight and is the oil richest known vegetal tissue [23]. Our goal is to understand how this tissue achieves this result, in order to increase, by synthetic biology approaches, the yield in oil for crops grown in Europe. In a first milestone, oil palm tree genes relevant for oil synthesis from fatty acids will be transiently expressed in tobacco leaves.

In order to select relevant gene candidates, we performed transcriptome assemblies on high quality Illumina sequences. As an annotated genome is available [34], we performed genome-guided assemblies with TRINITY assembler [26]. The sequence reads (total 300 millions) came from 5 RNA independent isolates from 3 tissues: leaf (2 isolates), kernel (1 isolate) and mesocarp (2 isolates). Transcriptomes coming from duplicate isolates show a good level of overlap as regards the predicted transcripts.

Using expression specificity, abundance and transcript annotation from the genome, we selected genes or transcrpt isoforms candidates, as well as transcription factors. A set of 19 sequences has been retained for expression in tobacco leaves and is under genetic engineering processing.

The 5 transcriptomes were fused into a pan-transcriptome which will be used in another angle of the project. The yield and the composition of oil measured from wild-type palm tree specimens varies dramatically, indicating a high level of bio-diversity. We are currently doing a sampling campaign in Africa, RNA extracts will be sequenced and compared to our pan-genome to serve in variant detection (SNPs) and association genetics studies.

This work is a collaboration between Pleiade team and UMR 5200 CNRS/Université de Bordeaux.