Metabolite profiling reveals the influence of grapevine genetic distance on the chemical signature of juices

BACKGROUND

Yield, disease tolerance, and climate adaptation are important traits in grapevine genetic breeding programs. Selection for these characteristics causes unpredictable changes in primary and specialized metabolism, affecting the physicochemical properties and chemical composition of the berries and their processed products, juice, and wine. In this study, we investigated the influence of the genetic distance between grapevine genotypes on the chemical signatures of the juices, by integrating comprehensive metabolic profiling to genetic analyses.

RESULTS

The studied grapevine cultivars exhibited low genetic diversity. Breeding for agronomic traits promoted higher contents of soluble sugars, total phenolics, and anthocyanins in the juices. Untargeted juice metabolomics identified a total of 147 metabolites, consisting of 30 volatiles, 21 phenolics, and 96 ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) features. Juices from grapes of the most recent cultivars exhibited increased levels of trans-resveratrol, catechin, and luteolin. The blend of volatiles from juices of later cultivars was also more complex, consisting of 29 distinct metabolites in 'BRS Magna'. Grapes from 'BRS Carmem', an intermediate cultivar, gave the most divergent UHPLC-MS juice profile.

CONCLUSION

Contents of soluble solids, total phenolics, and anthocyanins in grape juices were increased by controlled crosses and hybrid selection. Integrative analyses demonstrated that the juices' metabolic profiles accurately represent the cultivars' genetic distances. Juices from 'BRS Violeta' and 'BRS Magna' show relevant positive association with health-related phenolics and a distinct set of odor volatiles, although these characteristics were specifically sought by breeding. © 2023 Society of Chemical Industry.

Comparative analysis indicates a simple protocol for DNA extraction of the aromatic plant Lippia alba

An efficient method of genomic DNA extraction that provides high quality and yield is a crucial pre-requisite and limiting factor in plant genetic analysis. However, pure genomic DNA can be challenging to obtain from some plant species due to their sugar and secondary metabolite contents. Lippia alba is an important aromatic and medicinal plant, chemically characterized by the presence of tannins, flavonoids, anthocyanins, and essential oils, which interfere with the extraction of pure genomic DNA. In this scenario, optimizing the extraction methods and minimizing the effects of these compounds are necessary. This study compares six plant DNA extraction protocols based on the CTAB method. The quality and quantity of DNA samples obtained were determined by physical appearance by electrophoresis in agarose gels and spectrophotometry. The results highlight the difficulty in obtaining pure and clear bands for all tested methods, except for the polyvinylpyrrolidone (PVP)-based protocol created by our team, which was the better option for obtaining high-quality genomic DNA of L. alba. We conclude that adding PVP-40 into DNA extraction buffers can optimize the DNA extraction of L. alba and indicate this protocol for DNA extraction from other aromatic plants.

Overexpression of CsSAMT in Citrus sinensis Induces Defense Response and Increases Resistance to Xanthomonas citri subsp. citri

Citrus canker is a destructive disease caused by Xanthomonas citri subsp. citri, which affects all commercial sweet orange (Citrus sinensis [L.] Osbeck) cultivars. Salicylic acid (SA) and systemic-acquired resistance (SAR) have been demonstrated to have a crucial role in mediating plant defense responses against this phytopathogen. To induce SAR, SA is converted to methyl salicylate (MeSA) by an SA-dependent methyltransferase (SAMT) and translocated systemically to prime noninfected distal tissues. Here, we generated sweet orange transgenic plants (based on cvs. Hamlin and Valencia) overexpressing the SAMT gene from Citrus (CsSAMT) and evaluated their resistance to citrus canker. We obtained four independent transgenic lines and confirmed their significantly higher MeSA volatilization compared to wild-type controls. Plants overexpressing CsSAMT showed reduced symptoms of citrus canker and bacterial populations in all transgenic lines without compromising plant development. One representative transgenic line (V44SAMT) was used to evaluate resistance response in primary and secondary sites. Without inoculation, V44SAMT modulated CsSAMT, CsNPR1, CsNPR3, and CsWRKY22 expression, indicating that this plant is in a primed defense status. The results demonstrate that MeSA signaling prompts the plant to respond more efficiently to pathogen attacks and induces immune responses in transgenic plants at both primary and secondary infection sites.

Chemophenetics as a Tool for Distinguishing Morphotypes of Annona emarginata (Schltdl.) H. Rainer

Annona emarginata (Annonaceae) has two morphological variations (A. emarginata 'mirim' and A. emarginata 'terra-fria'). The species has agricultural value and produces specialized metabolites of pharmacological interest. The objective of this work was to analyze whether chemical and morphological differences contribute to differentiate A. emarginata 'terra-fria' from A. emarginata 'mirim', as chemophenetic variations of A. emarginata. The analysis of chemical compounds was based on the quantification, profile of root alkaloids and on the leaves volatile profile, together with morphometric analyses of the leaf blade. The samples were collected in three phenological stages (flowering, fruiting, and vegetative) at two places in São Paulo, Brazil. Differences in the composition of the alkaloid profile and leaf volatiles (in both places and in the three phenological stages) allowed us to separate the two morphotypes by multivariate statistical analysis. These differences agreed with the leaf blade morphology and flower color. This first chemophenetic report of A. emarginata demonstrates that, in addition to morphological variations, the specialized metabolism of roots and leaves can be phytochemical characters, which suggest the existence of at least morphochemotypes of A. emarginata.

Influence of Mycosphaerella and Teratosphaeria leaf diseases on chemical composition of essential oils of Eucalyptus globulus and effect of these essential oils on ascospores germination

In a first step, essential oils were extracted from Eucalyptus globulus leaves, healthy and with symptoms and signs of Mycosphaerella leaf disease (MLD) and Teratosphaeria leaf disease (TLD), in two leaf stages. Stage 1: sessile, oval leaves covered by a waxy layer of a bluish colour, with opposite phyllotaxis, inserted along stems of quadrangular section. Stage 2: narrow and sickle leaves with a greyish green surface, mainly on the abaxial surface, inserted in alternating pairs along rounded stems. The essential oils were extracted by hydrodistillation and were analyzed by gas chromatography coupled with mass spectrometry. Chemical composition data and percentages of essential oil constituents were submitted to cluster analysis and principal component analysis. In a second step, under in vitro conditions, was evaluated the germination of Teratosphaeria nubilosa (one of the causal agents of TLD) ascospores in contact with the four types of essential oils extracted. The evaluations were performed at 24, 48 and 72 h after the experiments were assembled. The present study made it possible to distinguish and identify the chemical composition of essential oils from the eucalypt leaves used, and allowed 1,8-cineole to be identified as the major component for the essential oils investigated. The contact between essential oils and T. nubilosa spores allowed to prove the inhibition of the ascospores germination, being more efficient for the essential oils extracted from materials with the disease, which presented high amounts of 1,8-cineole.

Essential Oils of New Lippia alba Genotypes Analyzed by Flow-Modulated Comprehensive Two-Dimensional Gas Chromatography (GC×GC) and Chemometric Analysis

Lippia alba (Mill.) N. E. Br. (Verbenaceae) is an aromatic shrub whose essential oils have stood out as a promising source for application in several industrial fields. In this study, the essential oils chemical characterization of eight new L. alba genotypes was performed. The selected materials were collected from the Active Germplasm Bank of the Agronomic Institute and the essential oils were extracted by hydrodistillation. Flow-modulated comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) was employed for chemical characterization and evaluation of possible co-eluted compounds. In addition, the chemical analyses were submitted to multivariate statistical analyses. From this investigation, 73 metabolites were identified in the essential oils of the genotypes, from which α-pinene, β-myrcene, 1,8-cineole, linalool, neral, geranial, and caryophyllene oxide were the most abundant compounds among the accessions. This is the first report disclosing α-pinene in higher amounts in L. alba (19.69%). In addition, sabinene, trans-verbenol, myrtenol, (E)-caryophyllene, α-guaiene, germacrene D, and α-bulnesene were also found in relevant quantities in some of the genotypes, and myrtenal and myrtenol could be well separated through the second dimension. Such results contributed to the understanding of the chemical composition of those new genotypes, being important to drive a future industrial applicability and studies in genetic breeding.

Biogenic Amines and the Antioxidant Capacity of Juice and Wine from Brazilian Hybrid Grapevines

Some biogenic amines (BAs) are used as quality markers in grape-derived products. The prolife of 9 BAs was determined in juices and wines elaborated from hybrid grapes. Low levels of histamine, tyramine and cadaverine were found. Juices elaborated from 'BRS Rúbea' showed the highest tyramine levels (1.56 mg/L), while no histamine was found in wines elaborated from 'Seleção 34' and its higher content was detected in 'BRS Carmem' (3.55 mg/L). Juices elaborated from 'BRS Violeta' showed elevated content (472.88 mg/L) of total phenolic compounds (TPC) and mono-hydrated serotonin (6.20 mg/L), and wines elaborated from 'Violeta' presented a high serotonin mono-hydrate content (23.63 mg/L) and high antioxidant activity with FRAP test (77.24 mmol FeSO₄/L). Juices elaborated from hybrid grapes 'BRS Violeta' and wines from 'BRS Violeta', 'Seleção 34' and 'Seleção 13' had high levels of bioactive compounds, emphasizing the great potential of these cultivars for winemaking.

Kinetin establish the volatile chemical profile after rhizome dormancy is released in Curcuma zedoaria (Christm.) Roscoe

The aim of this work was to provide information about kinetin effects on chemical volatile profile of Curcuma zedoaria (Christm.) Roscoe after several days of plant dormancy release. Rhizomes of C. zedoaria were immersed in four kinetin concentrations (0, 50, 100, 150 mg ml^-1, n = 12 by each concentration) for 30 min. After 240 h of treatment, root length (mm), bud break (%) and bud speed index (BSI) were measured, and three rhizomes at 24 h and 240 h were collected for chemical volatile profile analysis by application of headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Kinetin does not alter morphological aspects of the bud dormancy releasing, but drastically changes metabolic aspects of volatile production on C. zedoaria rhizomes, by the selection of several monoterpenes, such as camphene, sabinene, isoborneol, borneol, 1,8-cineole. We assume that kinetin application maintain monoterpene production as a consequence of its signaling over dormancy release.

Nitrogen in the defense system of Annona emarginata (Schltdl.) H. Rainer

The concentration of nitrogen can generate different strategies in plants in response to stress. In this study, we investigated how nitrogen concentration interferes with the defense system of Annona emarginata. Low concentrations of nitrogen increased the allocation of photosynthetic resources to carbon metabolism, resulting in an increase in the synthesis of volatile substances involved in signaling and defense that contributed to antioxidant enzymes in overcoming stress. The availability of nitrogen at 5.62 mM concentration might have helped to induce increased resistance in the plants because at this concentration, signaling substances and defense substances (monoterpenes and sesquiterpenes) were observed. Plants cultivated with the highest nitrate concentration displaced energy for the reduction of this ion, likely forming nitric oxide, a signaling molecule. This condition, together with the decrease in carbon skeletons, may have contributed to the lower synthesis of volatile substances of the specialized metabolism that are also involved with signaling. Varying the nitrogen in Annona emarginata cultivation revealed that depending on the concentration, volatile substances show higher or lower synthesis and participation in the system of signaling and defense in the plant. These results may suggest that volatile substances participate in resistance to pests and diseases, which is a necessary condition for Annona emarginata to be preferentially used as rootstock for Annona x atemoya.

Herbivory by leaf-cutter ants changes the glandular trichomes density and the volatile components in an aromatic plant model

Herbivory can induce several structural and functional alterations in the plant secretory system. Glandular trichomes are the main sites of production of volatile organic compounds (VOCs) with several chemical properties in Lamiaceae species. Ocimum species usually have three morphotypes of glandular trichomes (morphotype I is peltate and has a wide four-celled head; morphotype II is capitate and has a unicellular head; and morphotype III is capitate with a bicellular head) which produce a great amount of terpenes, although other chemical categories of substances are also produced. Despite the abundance of trichomes producing important anti-herbivory components in their leaves, the association between Ocimum species and leaf-cutter ants has been commonly registered in Brazil. We investigated the effect of leaf-cutter ant attack on the density of the glandular trichomes and on the chemistry of the VOCs released from leaves of O. gratissimum. Plants were subjected to Acromyrmex rugosus attack until 90 % of leaves were removed. After 40 days from the leaf-cutter attack, both treatments were sampled. The glandular trichome density was analysed by scanning electron microscopy. The VOCs were extracted utilizing headspace solid-phase microextraction (HS-SPME) technique and analysed by gas chromatography. Generally, the density of glandular trichomes increased in the adaxial leaf surface of the attacked plants. However, we bring novelties on this topic since we analysed the density of each morphotype separately. The morphotype I decreased in the abaxial leaf surface, and increased in the adaxial leaf surface; the morphotype II increased in both leaf surfaces; and the morphotype III decreased in the abaxial leaf surface and remained constant in the adaxial leaf surface of attacked plants. In leaves of attacked plants, the (Z)-β-ocimene increased by 50 %, the α-selinene by 13 % and the germacrene D by 126 %, whereas the eugenol decreased by 70 %. Our data point to a differential response of each glandular morphotype in O. gratissimum and are consistent with the idea of a compartmentalization of functions among the different glandular morphotypes in the plant defence against environmental factors.

PEG-induced osmotic stress in Mentha x piperita L.: Structural features and metabolic responses

The present study investigated whether osmotic stress induced by the exposure of peppermint (Mentha x piperita L.) to moderate and severe stress for short periods of time changes the plant's physiological parameters, leaf anatomy and ultrastructure and essential oil. Plants were exposed to two levels of polyethyleneglycol (50 g L(-1) and 100 g L(-1) of PEG) in a hydroponic experiment. The plants exposed to 50 g L(-1) maintained metabolic functions similar to those of the control group (0 g L(-1)) without changes in gas exchange or structural characteristics. The increase in antioxidant enzyme activity reduced the presence of free radicals and protected membranes, including chloroplasts and mitochondria. In contrast, the osmotic stress caused by 100 g L(-1) of PEG inhibited leaf gas exchange, reduced the essential oil content and changed the oil composition, including a decrease in menthone and an increase in menthofuran. These plants also showed an increase in peroxidase activity, but this increase was not sufficient to decrease the lipid peroxidation level responsible for damaging the membranes of organelles. Morphological changes were correlated with the evaluated physiological features: plants exposed to 100 g L(-1) of PEG showed areas with collapsed cells, increases in mesophyll thickness and the area of the intercellular space, cuticle shrinkage, morphological changes in plastids, and lysis of mitochondria. In summary, our results revealed that PEG-induced osmotic stress in M. x piperita depends on the intensity level of the osmotic stress applied; severe osmotic stress changed the structural characteristics, caused damage at the cellular level, and reduced the essential oil content and quality.

New loci of Lychnophora ericoides and transferability to Lychnophora pinaster, endangered medicinal species from Brazil

Lychnophora ericoides and Lychnophora pinaster are species used in popular medicine as analgesic or anti-inflammatory agents to treat contusions, rheumatism, and insect bites. In this study, 21 simple sequence repeat loci of L. ericoides were developed and transferred to L. pinaster. Three populations of L. ericoides and 2 populations of L. pinaster were evaluated; they were collected in the State of Minas Gerais. Population parameters were estimated, and the mean values of observed and expected heterozygosity were 0.297 and 0.408 (L. ericoides) and 0.228 and 0.310 (L. pinaster), respectively. Greater genetic variability was observed within populations than between populations of L. ericoides (62 and 37%) and L. pinaster (97 and 2.8%). These results provide information for genetic conservation and taxonomic studies of these endangered species.

Chemical composition and larvicidal activity against Aedes aegypti larvae of essential oils from four Guarea species

The essential oils of four Guarea species collected at Manaus (Amazonas, Brazil) were obtained by hydrodistillation and analyzed by GC-MS. Except for one diterpene detected, the compounds identified in the essential oils were hydrocarbons and oxygenated sesquiterpenes. The major sesquiterpenes were alpha-santalene (26.26%) and alpha-copaene (14.61%) from G. convergens branches; caryophyllene epoxide (40.91%) and humulene epoxide II (14.43%) from G. humaitensis branches; cis-caryophyllene (33.37%) and alpha-trans-bergamotene (11.88%) from G. scabra leaves; caryophyllene epoxide (36.54%) in leaves and spathulenol (14.34%) in branches from G. silvatica. The diterpene kaurene (15.61%) was found in G. silvatica leaves. Larvicidal activity assay of essential oils against third-instar Aedes aegypti larvae revealed that at higher concentrations (500 and 250 microg/mL), all the essential oils caused 100% mortality after 24 h of exposure. The most active essential oils were those of G. humaitensis branches (LC(50) 48.6 microg/mL), G. scabra leaves (LC(50) 98.6 microg/mL) and G. silvatica (LC(50) 117.9 microg/mL). The differences in the toxicity of essential oils of Guarea species on A. aegypti are due to qualitative and quantitative variations of the components, therefore the larvicidal effect may be due to higher amount of the sesquiterpenes with caryophyllane skeleton.

Chemical composition and antimicrobial activity of the essential oil of Cordiaverbenacea D.C

Cordiaverbenacea D.C. (Boraginaceae) is found along the coastal regions of Brazil, from the Amazon basin to the southernmost state of Rio Grande do Sul. The aerial parts of this plant have been used in folk medicine since colonial times for their anti-rheumatic, anti-inflammatory, analgesic and healing properties. The objectives of this study were: the extraction of the essential oil of the aerial parts of this species and quantification of the yield thereof; the identification and quantification of the principal components of the essential oil; and the determination of its antimicrobial activity by plate diffusion method. The yield of essential oil was 0.19% (v/w) in relation to the fresh flowering aerial parts and 0.23% (v/w) of the leaves. The main constituents of the essential oil, identified by gas chromatography/mass spectrometry (GC/MS), were alpha-pinene (29.69%), trans-caryophyllene (25.27%) and aloaromadendrene (9.99%). The Gram-positive bacteria and yeast tested were sensitive to the essential oil of Cordiaverbenacea D.C., but most of the Gram-negative bacteria were resistant.