Next-Generation Transcriptome Assembly for Plukenetia volubilis

Plukenetia volubilis is a nutraceutical oleaginous plant native to the Peruvian Amazon. Its seed oil contains high levels of polyunsaturated fatty acids (linoleic and linolenic), making it suitable for use in disease prevention and as a dietary supplement. Here we used high-throughput RNA sequencing (RNA-seq) to obtain the reference transcriptome for this species, establishing a critical genomic resource necessary for future genetics studies. Leaves of one adult individual of P. volubilis were collected in the Amazon rainforest (Brazil), and immediately frozen in liquid nitrogen and lyophilized. Total RNA was isolated and converted into cDNA prior to sequencing using an Illumina NextSeq platform. A total of 86,762,978 raw reads (paired-end read of 151 length) were filtered by quality with Trimmomatic and assembled into 138,600 transcripts with Trinity. The P. volubilis de novo transcriptome assembly contains 126,435 unigenes represented by 56 Mbp, with a median (mean) contig length of 284 bp (404 bp) and a GC content of 43.95%. Unigenes were annotated for their putative functions based on Arabidopsis thaliana transcriptme database. Total of 11,673 annotated unigenes were categorized into 31 functional groups under Gene Ontology terms. In the biological process category, cellular processes (39.3%) and metabolic processes (36.6%) were the predominant groups. For cellular component category the predominant were cell part (53.6%) and organelle (33.6%). The main distributions in the molecular function category were catalytic activity (38.4%) and binding (35.4%). This is a critical resource to be used for the development of new molecular tools for conservation genetics and evolutionary studies.