Changes in Phenolics and Fatty Acids Composition and Related Gene Expression during the Development from Seed to Leaves of Three Cultivated Cardoon Genotypes.

Giulia Graziani,Francesca Sparvoli,Marina Tucci,Luana Izzo,Monica De Palma,Teresa Docimo,Alberto Ritieni

doi:10.3390/antiox9111096

Abstract

Cultivated cardoon (Cynara cardunculus var. altilis) has long been used as a food and medicine remedy and nowadays is considered a functional food. Its leaf bioactive compounds are mostly represented by chlorogenic acids and coumaroyl derivatives, known for their nutritional value and bioactivity. Having antioxidant and hepatoprotective properties, these molecules are used for medicinal purposes. Apart from the phenolic compounds in green tissues, cultivated cardoon is also used for the seed oil, having a composition suitable for the human diet, but also valuable as feedstock for the production of biofuel and biodegradable bioplastics. Given the wide spectrum of valuable cardoon molecules and their numerous industrial applications, a detailed characterization of different organs and tissues for their metabolic profiles as well as an extensive transcriptional analysis of associated key biosynthetic genes were performed to provide a deeper insight into metabolites biosynthesis and accumulation sites. This study aimed to provide a comprehensive analysis of the phenylpropanoids profile through UHPLC-Q-Orbitrap HRMS analysis, of fatty acids content through GC-MS analysis, along with quantitative transcriptional analyses by qRT-PCR of hydroxycinnamoyl-quinate transferase (HQT), stearic acid desaturase (SAD), and fatty acid desaturase (FAD) genes in seeds, hypocotyls, cotyledons and leaves of the cardoon genotypes “Spagnolo”, “Bianco Avorio”, and “Gigante”. Both oil yield and total phenols accumulation in all the tissues and organs indicated higher production in “Bianco Avorio” and “Spagnolo” than in “Gigante”. Antioxidant activity evaluation by DPPH, ABTS, and FRAP assays mirrored total phenols content. Overall, this study provides a detailed analysis of tissue composition of cardoon, enabling to elucidate value-added product accumulation and distribution during plant development and hence contributing to better address and optimize the sustainable use of this natural resource. Besides, our metabolic and transcriptional screening could be useful to guide the selection of superior genotypes.

Highlights

Cynara cardunculus L. var. altilis DC., the cultivated cardoon, belongs to the Asteraceae family and, with its sister species globe artichoke (Cynara cardunculus var. scolymus) and their common ancestor wild cardoon (Cynara cardunculus var. sylvestris), participates in the small Cynara genus
This study aimed to provide a comprehensive analysis of the phenylpropanoids profile through UHPLC-Q-Orbitrap HRMS analysis, of fatty acids content through GC-MS analysis, along with quantitative transcriptional analyses by qRT-PCR of hydroxycinnamoyl-quinate transferase (HQT), stearic acid desaturase (SAD), and fatty acid desaturase (FAD) genes in seeds, hypocotyls, cotyledons and leaves of the cardoon genotypes “Spagnolo”, “Bianco Avorio”, and “Gigante”
The UHPLC technique coupled to Orbitrap-HRMS showed that the different analyzed cardoon tissues and organs contained the same phenolic qualitative profile, but their relative abundances were considerably different between samples and genotypes

Summary

Introduction

Cynara cardunculus L. var. altilis DC., the cultivated cardoon, belongs to the Asteraceae family and, with its sister species globe artichoke (Cynara cardunculus var. scolymus) and their common ancestor wild cardoon (Cynara cardunculus var. sylvestris), participates in the small Cynara genus. Altilis DC., the cultivated cardoon, belongs to the Asteraceae family and, with its sister species globe artichoke Scolymus) and their common ancestor wild cardoon Cardoon and artichoke originate from the Mediterranean area [1], where they are mostly cultivated. Artichoke is famous as a food crop for its edible immature inflorescences (heads) and is produced in America and Asia, while cardoon, having a similar composition, has a restricted traditional food use in Mediterranean countries, though its cultivation for industrial purposes is increasing. Cultivated cardoon is gaining interest as a multipurpose crop, due to the versatility of its main products, which offer a wide spectrum of applications [2]. Most of the health-beneficial compounds are polyphenols, which are present in all plant organs, though in higher amounts in leaves and seeds [7]

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