title: A volatolomic approach for studying plant variability: the case of selected Helichrysum species (Asteraceae).
abstract: The species of Helichrysum sect. Stoechadina (Asteraceae) are well-known for their secondary metabolite content and the characteristic aromatic bouquets. In the wild, populations exhibit a wide phenotypic plasticity which makes critical the circumscription of species and infraspecific ranks. Previous investigations on Helichrysum italicum complex focused on a possible phytochemical typification based on hydrodistilled essential oils. Aims of this paper are three-fold: (i) characterizing the volatile profiles of different populations, testing (ii) how these profiles vary across populations and (iii) how the phytochemical diversity may contribute in solving taxonomic problems. Nine selected Helichrysum populations, included within the H. italicum complex, Helichrysum litoreum and Helichrysum stoechas, were investigated. H. stoechas was chosen as outgroup for validating the method. After collection in the wild, plants were cultivated in standard growing conditions for over one year. Annual leafy shoots were screened in the post-blooming period for the emissions of volatile organic compounds (VOCs) by means of headspace solid phase microextraction coupled with gas-chromatography and mass spectrometry (HS-SPME-GC/MS). The VOC composition analysis revealed the production of overall 386 different compounds, with terpenes being the most represented compound class. Statistical data processing allowed the identification of the indicator compounds that differentiate the single populations, revealing the influence of the geographical provenance area in determining the volatile profiles. These results suggested the potential use of VOCs as valuable diacritical characters in discriminating the Helichrysum populations. In addition, the cross-validation analysis hinted the potentiality of this volatolomic study in the discrimination of the Helichrysum species and subspecies, highlighting a general congruence with the current taxonomic treatment of the genus. The consistency between this phytochemical approach and the traditional morphometrical analysis in studying the Helichrysum populations supports the validity of the VOC profile in solving taxonomic problems.
authors: Department of Pharmaceutical Sciences (DISFARM), University of Milan, Via Mangiagalli 25, I-20133 Milan, Italy.
authors: Claudia
authors: C
authors: Giuliani
authors: Department of Biology (BIO), University of Florence, Via G. La Pira 4, I-50121 Florence, Italy.
authors: Lorenzo
authors: L
authors: Lazzaro
authors: Department of Biology (BIO), University of Florence, Via G. La Pira 4, I-50121 Florence, Italy.
authors: Roberto
authors: R
authors: Calamassi
authors: Department of Plant, Soil and Environmental Sciences (DISPAA), University of Florence, Piazzale delle Cascine 28, I-50144 Florence, Italy.
authors: Luca
authors: L
authors: Calamai
authors: Mass Spectrometry Center (CISM), University of Florence, Via U. Schiff 6, I-50019 Sesto F.no, Florence, Italy.
authors: Riccardo
authors: R
authors: Romoli
authors: Department of Pharmaceutical Sciences (DISFARM), University of Milan, Via Mangiagalli 25, I-20133 Milan, Italy. Electronic address: gelsomina.fico@unimi.it.
authors: Gelsomina
authors: G
authors: Fico
authors: Department of Biology (BIO), University of Florence, Via G. La Pira 4, I-50121 Florence, Italy.
authors: Bruno
authors: B
authors: Foggi
authors: Department of Biology (BIO), University of Florence, Via G. La Pira 4, I-50121 Florence, Italy.
authors: Marta
authors: M
authors: Mariotti Lippi
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D036562:Helichrysum / Q000737:chemistry / Q000235:genetics*; D015394:Molecular Structure; D009822:Oils, Volatile / Q000737:chemistry; D055549:Volatile Organic Compounds / Q000032:analysis* / Q000737:chemistry
chemical_list: D009822:Oils, Volatile; D055549:Volatile Organic Compounds
keywords: HS-SPME-GC/MS; Helichrysum litoreum; Helichrysum microphyllum subsp. tyrrhenicum; Helichrysum pseudolitoreum; Helichrysum sect. Stoechadina species: Helichrysum italicum subsp. italicum; Helichrysum stoechas (Asteraceae); Mediterranean; Taxonomy; VOCs