De novo transcriptome assembly and SSR marker development in apricot (Prunus armeniaca)


Abstract: Apricot (Prunus armeniaca) is an important fruit crop worldwide. We have performed a de novo transcriptome assembly for 7 apricot accessions (`Stark Early Orange' (SEO), `Hacıhaliloğlu' (HH), `Perfection', `Iğdır', `Roxana', `Esen1', and `Esen2'), which yielded a total number of transcripts ranging from 30,363 for `SEO' to 59,751 for `Iğdır'. The pool of the reads produced from 7 accessions were assembled into 85,766 transcripts, with an average of 1165.69 nt. Functional annotation (Gene Ontology- GO and Kyoto Encyclopedia of Genes and Genomes- KEGG) was performed successfully for the transcripts. Simple sequence repeats (SSRs) were searched in the transcript pool and 14,722 di-, tri- tetra-, penta-, and hexanucleotide motif loci with a minimum of 5 repetitions for all motifs were identified. Primers were designed for 206 loci, and 72 of them were found to be polymorphic by amplifying diverse 24 apricot accessions, including 7 Plum Pox Virus (PPV)-resistant and 17 PPV-susceptible accessions. In order to test the amplification success of publicly available genomic SSRs (gSSRs) for diverse apricot accessions, an additional 88 published Prunus gSSRs were characterized amplifying the same 24 apricots and only 54 (62%) produced polymorphic bands. The new EST-SSRs could be a reliable source of primers for characterization and mapping studies of apricots, especially because they mostly flank easily scorable tri- and tetranucleotide repeats.

Keywords: Microsatellite, molecular markers, functional annotation

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