First set of microsatellite markers for immortelle (Helichrysum italicum (Roth) G. Don): A step towards the selection of the most promising genotypes for cultivation

Abstract

Immortelle (Helichrysum italicum (Roth) G. Don), also known as curry plant, is a herbaceous perennial plant with documented biological properties that contribute to its attractiveness and use in the cosmetic, pharmaceutical, and food industry. Availability of DNA markers can significantly improve the knowledge of complex genetics and biochemistry of this aromatic plant. To improve in-depth genetic studies, high-throughput sequencing of a genomic DNA has been performed and a set of 24 SSR markers was developed. In total, 17,025,076 high quality reads were assembled in contigs with the cumulative length of 258.6 Mbp. Genome-wide microsatellite sequences were identified in 8.19% (36,882) contigs, among which dinucleotide (71.2%) and trinucleotide (24.4%) repeats were the most abundant. Twenty-four finally selected microsatellite loci (including di- and tri-nucleotides) which exhibited polymorphism with unambiguous and reproducible amplification products, were used for detailed genetic diversity analysis on a set of 28 H. italicum samples. The Unweighted Pair Group Method with Arithmetic Mean (UPGMA) method based on the Jaccard index differentiated 27 genotypes into two main clusters according to their geographical origin (Northern and Southern Adriatic region), whereas the commercially available plant did not cluster with other H. italicum individuals and morphological evaluation confirmed that it belongs to Helichrysum angustifolium (Lam.) DC. The great diversity of H. italicum samples from the Adriatic observed by new microsatellites will serve for selection of most promising genotypes for propagation and their implementation in agricultural production. The first set of microsatellites developed in the present study provides a valuable resource of DNA markers for further breeding programs, germplasm characterization, and cross-species transferability studies.