Exploration of genetic, morphological and essential oil variation reveals tools for the authentication and breeding of Salvia pomifera subsp. calycina (Sm.) Hayek

Abstract

Salvia pomifera subsp. calycina (Sm.) Hayek (Lamiaceae), is an Eastern Mediterranean element, which is used in traditional medicine and cuisine in the same manner as S. fruticosa Mill. and S. officinalis L.. The essential oil (EO) and the extracts of S. pomifera possess bioactive compounds with anti-proliferative, anticholinesterase, antioxidant, antiviral and antifungal properties. In this study, the chemical (EO), genetic (DNA microsatellites, SSRs) and morphological diversity of forty-nine individuals of Salvia pomifera subsp. calycina, originating from five natural populations of the Peloponnese (Greece) were determined, in order to explore the potential for successful breeding and to reveal tools and biomarkers for identification and authentication. Chemical and genetic analyses revealed high levels of variation both within and among populations, while morphological analysis mainly within populations. Essential oil yield ranged from 1.79 to 5.79 ml 100 g^-1 dry wt, among individuals while β-thujone ranged from 6.04 to 64.75%. Consistency was found in the EO yield and composition of specific individuals, when sampled during the same period, for three consecutive years, while the analysis during spring and summer months showed differentiation that still retained individual's discrimination. Genetic analysis using SSRs showed that the observed population heterozygosity (H_o) ranged from 0.48 to 0.67, while high number of private alleles were revealed in all populations. Considerable genetic differentiation was observed among the three Salvia taxa (S. pomifera subsp. calycina, S. fruticosa, S. officinalis) (Fst values ranged from 0.27 to 0.48) and lower among S. pomifera subsp. calycina populations (Fst values ranged from 0.06 to 0.13). The great variation that was revealed in all measured traits, in combination with the demonstrated, genetically based, consistency of their EO yield and composition, advocates to a successful breeding, whereas SSR genotyping presents a strong identification and authentication tool.

Keywords: Apple sage; Authentication; Breeding; DNA microsatellite markers (SSRs); Essential oils; Genetic analysis; Lamiaceae; Morphological traits; Salvia pomifera subsp. calycina; Thujones.