Transcriptome analysis across various mesocarp developmental stages of mpob-Angola dura

Abstract

Angolan germplasm materials are being evaluated for their potential use in oil palm breeding programmes. Large fruits characteristic of some Angola dura palms have provided breeders with a source of favourable traits for introgression into the current planting materials. With the aim of understanding molecular regulation during mesocarp development, maturation and ripening of Angola dura palms, efforts were initiated to profile the expression of transcripts across nine different developmental stages of mesocarp tissues. A 36 675 total gene set was identified from ribonucleic acid (RNA) sequencing with 24 226 transcripts successfully annotated with the Plant Reference Sequence (RefSeq) Database using BLASTX, while 12 449 transcripts had no hit to any known genes. Pairwise T-test was performed using TIGR Multiexperiment Viewer and a total of 21 261 transcripts were identified as significant across all the pairwise comparisons. BLAST2GO analysis resulted in the annotation of 13 996 unigenes with various gene ontology (GO) terms. Transcripts associated with lipid metabolic process were highly expressed during lag phase preceding the lipid biosynthesis [10 to 12 weeks after anthesis (WAA)] and fruit maturation (18 to 20 WAA) stages. Further annotation of the unigenes with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway resulted in the identification of 279, 757 and 142 transcripts related to lipid metabolism, carbohydrate metabolism and hormone metabolism, respectively. Detailed analysis of the expression data revealed that certain transcripts such as KAS I, FatA, DGAT, WRI1 and bZIP showed unique expression profiles in the MPOB-Angola dura as compared to the published data. The availability of these transcriptome datasets gives an insight into the transcriptional mechanisms controlling the Angolan dura fruit development, maturation and ripening.