Endives (Cichorium endivia L.) are popular vegetables, diversified into curly/frisée- and smooth/broad-leafed (escaroles) cultivar types (cultigroups), and consumed as fresh and bagged salads. They are rich in sesquiterpene lactones (STL) that exert proven function on bitter taste and human health. The assembly of a reference transcriptome of 77,022 unigenes and RNA-sequencing experiments were carried out to characterize the differences between endives and escaroles at the gene structural and expression levels. A set of 3177 SNPs distinguished smooth from curly cultivars, and an SNP-supported phylogenetic tree separated the cultigroups into two distinct clades, consistently with the botanical varieties of origin (crispum and latifolium, respectively). A pool of 699 genes maintained differential expression pattern (core-DEGs) in pairwise comparisons between curly vs smooth cultivars grown in the same environment. Accurate annotation allowed the identification of 26 genes in the sesquiterpenoid biosynthesis pathway, which included several germacrene A synthase, germacrene A oxidase and costunolide synthase members (GAS/GAO/COS module), required for the synthesis of costunolide, a key precursor of lactucopicrin- and lactucin-like sesquiterpene lactones. The core-DEGs contained a GAS gene (contig83192) that was positively correlated with STL levels and recurrently more expressed in curly than smooth endives, suggesting a cultigroup-specific behavior. The significant positive correlation of GAS/GAO/COS transcription and STL abundance (2.4-fold higher in frisée endives) suggested that sesquiterpenoid pathway control occurs at the transcriptional level. Based on correlation analyses, five transcription factors (MYB, MYB-related and WRKY) were inferred to act on contig83192/GAS and specific STL, suggesting the occurrence of two distinct routes in STL biosynthesis.

In the framework of a project aimed to select some genotypes of Capsicum annum potentially exploitable for giving high‐quality products, this research compared the total content of some bioactive compounds (polyphenols, flavonoids, carotenoids and ascorbic acid) and the antioxidant activity between of two cultivars of “Corno di Toro” sweet peppers, commonly named “Lampo” and “Teseo.” They were also investigated for their in vitro antimicrobial action against different bacteria and fungi, as well as for their mutagenic and antimutagenic activities. A relevant content of the active compounds was found, showing cultivar Lampo a higher content of polyphenols and a greater antioxidant potential. The antimicrobial action was different, exhibiting the compounds from variety “Lampo” a discrete activity against Bacillus cereus, Escherichia coli and Penicillium expansum, whereas extracts from “Teseo” showed inhibition against E. coli and Debaryomyces hansenii. The antimutagenic activity, assayed with Ames test by using the Salmonella typhimurium Histidine‐requiring strain TA100, was significant, with a percentage of mutagenicity inhibition comparable to the negative control. The two cultivars could be of great interest as relevant polyphenols sources and for their antimicrobial and antimutagenic properties. PRACTICAL APPLICATIONS Sweet pepper (Capsicum annuum L.) is a broadly diffused plant. The information gathered from our work can contribute to a better selection of those genotypes of C. annum potentially exploitable for giving high‐quality products, in terms of biochemical compounds and antioxidant activity. With the emergence of antibiotic‐resistant microorganisms, it is reasonable to explore new sources of natural compounds with antibiotic activities: our study showed the possibility to use the extracts of two genotypes of a common edible plant, like sweet pepper, as harmless and economical antibacterial and antifungal compounds. In view of the fact that several human diseases, like cancer, are recognized as taking place from free radical damage, the inclusion in the diet of those genotypes of sweet pepper with noteworthy antimutagenic property could contribute in the prevention or limitation of such disease.

Stem-chicory of the “Catalogna” group is a vegetable consumed for bitter-flavored stems. Type and levels of bitter sesquiterpene lactones (STLs) participate in conferring bitterness in vegetables. The content of lactucin—and lactucopocrin-like STLs was higher in “Molfettese” than “Galatina” landrace stalks, regardless of the cultivation sites, consistently with bitterness scores and gustative differences. The “Galatina” transcriptome assembly resulted in 58,872 unigenes, 77% of which were annotated, paving the way to molecular investigation of the STL pathway. Comparative transcriptome analysis allowed the identification of 69,352 SNPs and of 1640 differentially expressed genes that maintained the pattern independently of the site. Enrichment analyses revealed that 4 out of 29 unigenes were up-regulated in “Molfettese” vs “Galatina” within the sesquiterpenoid pathway. The expression of two germacrene A -synthase (GAS) and one -oxidase (GAO) genes of the costunolide branch correlated positively with the contents of lactucin-like molecules, supporting that STL biosynthesis regulation occurs at the transcriptional level. Finally, 46 genes encoding transcription factors (TFs) maintained a differential expression pattern between the two varieties regardless of the growth site; correlation analyses among TFs, GAS, GAO gene expressions and STLs contents suggest that one MYB and one bHLH may act in the pathway.

Endive (Cichorium endivia L.), a vegetable consumed as fresh or packaged salads, is mostly cultivated outdoors and known to be sensitive to waterlogging in terms of yield and quality. Phenotypic, metabolic and transcriptomic analyses were used to study variations in curly- (‘Domari’, ‘Myrna’) and smooth-leafed (‘Flester’, ‘Confiance’) cultivars grown in short-term waterlog due to rainfall excess before harvest. After recording loss of head weights in all cultivars (6-35%), which was minimal in ‘Flester’, NMR untargeted profiling revealed variations as influenced by genotype, environment and interactions, and included drop of total carbohydrates (6–50%) and polyols (3–37%), gain of organic acids (2–30%) and phenylpropanoids (98–560%), and cultivar-specific fluctuations of amino acids (−37 to +15%). The analysis of differentially expressed genes showed GO term enrichment consistent with waterlog stress and included the carbohydrate metabolic process. The loss of sucrose, kestose and inulin recurred in all cultivars and the sucrose-inulin route was investigated by covering over 50 genes of sucrose branch and key inulin synthesis (fructosyltransferases) and catabolism (fructan exohydrolases) genes. The lowered expression of a sucrose gene subset together with that of SUCROSE:SUCROSE-1-FRUCTOSYLTRANSFERASE (1-SST) may have accounted for sucrose and kestose contents drop in the leaves of waterlogged plants. Two anti-correlated modules harbouring candidate hub-genes, including 1-SST, were identified by weighted gene correlation network analysis, and proposed to control positively and negatively kestose levels. In silico analysis further pointed at transcription factors of GATA, DOF, WRKY types as putative regulators of 1-SST.

Chicories produce a wide range of vegetables with important nutritional value. We determined the variation of sterol, total polyphenol, nitrate contents and antioxidant capacity (SC, TPC, NC, AC) in endive leaves and stem-chicory novel vegetables, cultivated in two Italian regions. Within a given area, the SC was similar in smooth- and curly leafed endives (106.3-176.0 mg/kg FW); sitosterol and stigmasterol were major fractions (45-56 versus 38-43%). The stem SC was independent of landrace (101.5-118.6 mg/kg FW); sitosterol prevailed on stigmasterol and fucosterol (73-76 versus 12-14% versus 8-9%); the latter reached 15.7 mg/kg FW, conferring value as potential antidiabetes food. The planting site affected the AC and TPC of endives (893.1-1571.4 μmTE/100 g FW, 30.8-76.1 GAE100/g FW) and chicory stems (729.8-1152.5 μmTE/100 g FW; 56.2-124.4 GAE100/g FW), while the NC was recurrently below dangerous thresholds. PCA showed that environment was the major cause of variation, though it modestly affected these parameters.