De Novo Sequencing and Analysis of the Transcriptomes of Five Tissues of Saba Banana (Musa balbisiana)

The Saba banana (Musa balbisiana) is an economically important triploid cooking banana endemic in the Philippines. The transcriptomes of the Saba leaf, flower, petiole, peel, and pulp were sequenced using the Illumina MiSeq technology. A total of 3,979,078 paired-end reads were generated. The sequences from the five tissues were separately assembled de novo using CLC Genomics Workbench algorithm based on de Bruijn graph. The sequence reads from the five tissues were also combined and assembled de novo generating 53,750 contigs consisted of 28,873,975 bases with a N50 of 619 bases and an average of 532 bases. The contigs were annotated through Blastx alignment and functionally characterized by gene ontology (GO) annotation. For RNA sequence analysis, the set of contigs of each of the transcriptomes were mapped back to the de novo assembled contigs of the combined transcripts of the five tissues. Gene expression levels were represented based on reads per kilobase per million (RPKM) values. Differentially expressed genes between tissues were statistically identified via Kal’s tests on proportions. To our knowledge this is the first transcriptome study on the Saba banana and could therefore serve as a good genomics resource for gene and marker discoveries which could eventually be useful in the improvement of the Saba variety by marker assisted selection and breeding.