Analysis of the oil biosynthesis transcripts of the Moringa oleifera Lam. mature seed embryos using RNA sequencing

Moringa oleifera seeds are capable of producing 40% edible oils that are gaining significance due to its nutritional advantages. Several studies have examined M. oleifera seed oil, nevertheless, these studies focused on the extraction of oil and methods of biodiesel production. There is a paucity of information on transcriptome level studies to determine the unigenes involved in oil biosynthesis metabolic pathways. The main objective of this study is to explore the transcriptome of the mature embryo of M. oleifera Lam. particularly the key genes related to oil biosynthesis. The transcriptome reflects the set of genes that are actively expressed at any given time produced in one or a population of cells in a given organism. Total RNA was extracted from 30 mature seed embryos obtained from 10 trees in Muñoz, Nueva Ecija, Philippines. RNA were pooled for cDNA library construction. Then, RNA-sequencing was done followed by de novo sequence assembly to provide a cost-effective and comprehensive means of transcriptome level information for M. oleifera. A total of 182,588 transcripts were generated in this study. Out of these transcripts, 3,556 unigenes are involved in oil biosynthesis. The most numerous group of unigenes are those involved in fatty acid biosynthesis with 1,009 unigenes, fatty acid catabolism with 982 unigenes and triacylglycerol catabolism with 608 unigenes. There are 33 unigenes encoding for transcription factors involved in regulating oil biosynthesis gene expression. This is the first transcriptome resource ever reported for M. oleifera mature seed embryo. These unigenes are unmatched in protein databases for M. oleifera. Hence, the transcriptome resource for the M. oleifera Lam. mature seed embryo generated in this study will be useful for the mapping of oil biosynthesis related genes and the understanding of metabolic pathways which could possibly be used to improve seed yield and oil content of M. oleifera.