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Hernández MDM, Castillo Río C, Blanco González SI, Menéndez CM. Phenolic profile changes of grapevine leaves infected with Erysiphe necator. PEST MANAGEMENT SCIENCE 2024; 80:397-403. [PMID: 37708311 DOI: 10.1002/ps.7769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/09/2023] [Accepted: 09/14/2023] [Indexed: 09/16/2023]
Abstract
BACKGROUND Powdery mildew in grapevine is caused by Erysiphe necator and its control requires many chemical treatments. Numerous efforts are being made to improve disease management to achieve crop sustainability goals. The exogenous induction of plant immune responses is one of the most encouraging strategies currently being developed. The objective of this research was to analyse differences in phenolic compound concentrations in E. necator-infected leaves of two varieties of Vitis vinifera, Tempranillo and Tempranillo Blanco, using ultra performance liquid chromatography coupled with mass spectrometry. To understand the susceptibility of the varieties, in vitro assays using whole leaves were done. RESULTS Differences in susceptibility between varieties were found in the early stage of the disease. In both varieties, total phenolic compounds were higher in infected leaves; however, hydroxycinnamic acid, anthocyanins and stilbenes were higher only in Tempranillo. Twenty-six compounds showed differential responses to the fungal disease in Tempranillo, but only two in Tempranillo Blanco: syringa resinol, which was not detected in diseased leaves; and gallocatechin, which increased at 5 days post inoculation. In Tempranillo, four anthocyanidins, six hydroxycinnamic acids, mainly feruloyl derivates, and epigallocatechin gallate were higher in infected leaves at the beginning of the infection, whereas (-)-epicatechin and protocatechuic hexoside contents were lower. CONCLUSION Disease-induced changes in phenolic compound biosynthesis were found. The increase in anthocyanidin content and flavan-3-ol galloylation could have a role in delaying E. necator growth in Tempranillo. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- María Del Mar Hernández
- Instituto de Ciencias de la Vid y el Vino (UR-ICVV-GR), Logroño, Spain
- Departamento de Agricultura y Alimentación, La Rioja University, Logroño, Spain
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Davosir D, Šola I, Ludwig-Müller J, Šeruga Musić M. Flavescence Dorée Strain-Specific Impact on Phenolic Metabolism Dynamics in Grapevine ( Vitis vinifera) throughout the Development of Phytoplasma Infection. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:189-199. [PMID: 38113060 PMCID: PMC10786034 DOI: 10.1021/acs.jafc.3c06501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/21/2023]
Abstract
Flavescence dorée phytoplasma (FDp) is a phytopathogenic bacterium associated with Grapevine yellowS disease, which causes heavy damage to viticultural production. Epidemiological data revealed that some FDp strains appear to be more widespread and aggressive. However, there is no data on mechanisms underlying the variable pathogenicity among strains. In this research, we employed chromatographic and spectrophotometric techniques to assess how two strains of FDp influence the levels of grapevine phenolic compounds, which are frequently utilized as indicative markers of stress conditions. The results pointed to the upregulation of all branches of phenolic metabolism through the development of infection, correlating with the increase in antioxidative capacity. The more aggressive strain M54 induced stronger downregulation of phenolics' accumulation at the beginning and higher upregulation by the end of the season than the less aggressive M38 strain. These findings reveal potential targets of FDp effectors and provide the first functional demonstration of variable pathogenicity between FDp strains, suggesting the need for future comparative genomic analyses of FDp strains as an important factor in exploring the management possibilities of FDp.
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Affiliation(s)
- Dino Davosir
- Department
of Biology, Faculty of Science, University
of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
- Faculty
of Biology, Technische Universität
Dresden, Zellescher Weg 20b, 01217 Dresden, Germany
| | - Ivana Šola
- Department
of Biology, Faculty of Science, University
of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
| | - Jutta Ludwig-Müller
- Faculty
of Biology, Technische Universität
Dresden, Zellescher Weg 20b, 01217 Dresden, Germany
| | - Martina Šeruga Musić
- Department
of Biology, Faculty of Science, University
of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
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Nutricati E, De Pascali M, Negro C, Bianco PA, Quaglino F, Passera A, Pierro R, Marcone C, Panattoni A, Sabella E, De Bellis L, Luvisi A. Signaling Cross-Talk between Salicylic and Gentisic Acid in the ' Candidatus Phytoplasma Solani' Interaction with Sangiovese Vines. PLANTS (BASEL, SWITZERLAND) 2023; 12:2695. [PMID: 37514309 PMCID: PMC10383235 DOI: 10.3390/plants12142695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023]
Abstract
"Bois noir" disease associated with 'Candidatus Phytoplasma solani' seriously compromises the production and survival of grapevines (Vitis vinifera L.) in Europe. Understanding the plant response to phytoplasmas should help to improve disease control strategies. Using a combined metabolomic and transcriptomic analysis, this work, therefore, investigated the phytoplasma-grapevine interaction in red cultivar Sangiovese in a vineyard over four seasonal growth stages (from late spring to late summer), comparing leaves from healthy and infected grapevines (symptomatic and symptomless). We found an accumulation of both conjugate and free salicylic acids (SAs) in the leaves of 'Ca. P. solani'-positive plants from early stages of infection, when plants are still asymptomatic. A strong accumulation of gentisic acid (GA) associated with symptoms progression was found for the first time. A detailed analysis of phenylpropanoids revealed a significant accumulation of hydroxycinnamic acids, flavonols, flavan 3-ols, and anthocyanin cyanidin 3-O-glucoside, which are extensively studied due to their involvement in the plant response to various pathogens. Metabolomic data corroborated by gene expression analysis indicated that phenylpropanoid biosynthetic and salicylic acid-responsive genes were upregulated in 'Ca. P. solani-positive plants compared to -negative ones during the observed period.
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Affiliation(s)
- Eliana Nutricati
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
| | - Mariarosaria De Pascali
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
| | - Carmine Negro
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
| | - Piero Attilio Bianco
- Department of Agricultural and Environmental Sciences, Production, Landscape, Agroenergy (DiSAA), University of Milan, Via Celoria 2, 20133 Milano, Italy
| | - Fabio Quaglino
- Department of Agricultural and Environmental Sciences, Production, Landscape, Agroenergy (DiSAA), University of Milan, Via Celoria 2, 20133 Milano, Italy
| | - Alessandro Passera
- Department of Agricultural and Environmental Sciences, Production, Landscape, Agroenergy (DiSAA), University of Milan, Via Celoria 2, 20133 Milano, Italy
| | - Roberto Pierro
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
| | - Carmine Marcone
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
| | - Alessandra Panattoni
- Department of Agriculture, Food and Environment (DAFE), University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Erika Sabella
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
| | - Luigi De Bellis
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
| | - Andrea Luvisi
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
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Ferrandino A, Pagliarani C, Pérez-Álvarez EP. Secondary metabolites in grapevine: crosstalk of transcriptional, metabolic and hormonal signals controlling stress defence responses in berries and vegetative organs. FRONTIERS IN PLANT SCIENCE 2023; 14:1124298. [PMID: 37404528 PMCID: PMC10315584 DOI: 10.3389/fpls.2023.1124298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 05/26/2023] [Indexed: 07/06/2023]
Abstract
Abiotic stresses, such as temperature, heat waves, water limitation, solar radiation and the increase in atmospheric CO2 concentration, significantly influence the accumulation of secondary metabolites in grapevine berries at different developmental stages, and in vegetative organs. Transcriptional reprogramming, miRNAs, epigenetic marks and hormonal crosstalk regulate the secondary metabolism of berries, mainly the accumulation of phenylpropanoids and of volatile organic compounds (VOCs). Currently, the biological mechanisms that control the plastic response of grapevine cultivars to environmental stress or that occur during berry ripening have been extensively studied in many worlds viticultural areas, in different cultivars and in vines grown under various agronomic managements. A novel frontier in the study of these mechanisms is the involvement of miRNAs whose target transcripts encode enzymes of the flavonoid biosynthetic pathway. Some miRNA-mediated regulatory cascades, post-transcriptionally control key MYB transcription factors, showing, for example, a role in influencing the anthocyanin accumulation in response to UV-B light during berry ripening. DNA methylation profiles partially affect the berry transcriptome plasticity of different grapevine cultivars, contributing to the modulation of berry qualitative traits. Numerous hormones (such as abscisic and jasmomic acids, strigolactones, gibberellins, auxins, cytokynins and ethylene) are involved in triggering the vine response to abiotic and biotic stress factors. Through specific signaling cascades, hormones mediate the accumulation of antioxidants that contribute to the quality of the berry and that intervene in the grapevine defense processes, highlighting that the grapevine response to stressors can be similar in different grapevine organs. The expression of genes responsible for hormone biosynthesis is largely modulated by stress conditions, thus resulting in the numeourous interactions between grapevine and the surrounding environment.
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Affiliation(s)
- Alessandra Ferrandino
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Grugliasco, Italy
| | - Chiara Pagliarani
- National Research Council, Institute for Sustainable Plant Protection (CNR-IPSP), Torino, Italy
| | - Eva Pilar Pérez-Álvarez
- Grupo VIENAP. Finca La Grajera, Instituto de Ciencias de la Vid y del Vino (ICVV), Logroño, La Rioja, Spain
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Wright AA, Shires M, Molnar C, Bishop G, Johnson A, Frias C, Harper SJ. Titer and Distribution of ' Candidatus Phytoplasma pruni' in Prunus avium. PHYTOPATHOLOGY 2022; 112:1406-1412. [PMID: 35021858 DOI: 10.1094/phyto-11-21-0468-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
'Candidatus Phytoplasma pruni' infection in cherries causes small, misshapen fruit with poor color and taste, rendering the fruit unmarketable. However, this is a disease with a long development cycle and a scattered, nonuniform symptom distribution in the early stages. To better understand the biology as well as the relationship between pathogen titer and disease expression, we carried out seasonal, spatial, and temporal examinations of 'Ca. P. pruni' titer and distribution in infected orchard-grown trees. Sequential sampling of heavily infected trees revealed marked seasonal patterns, with differential accumulation in woody stem and leaf tissues and, most notably, within fruit in the early stages of development from bloom to pit hardening. Furthermore, mapping phytoplasma distribution and titer in trees at different stages of infection indicated that infection proceeds through a series of stages. Initially, infection spreads basipetally and accumulates in the roots before populating aerial parts of the trees from the trunk upward, with infection of specific tissues and limbs followed by an increasing phytoplasma titer. Finally, we observed a correlation between phytoplasma titer and symptom severity, with severe symptom onset associated with three to four orders of magnitude more phytoplasma than mild symptoms. Cumulatively, these data aid in accurate sampling and management decision-making and furthers our understanding of disease development.
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Affiliation(s)
- A A Wright
- Department of Plant Pathology, Washington State University, Prosser, WA 99350
| | - M Shires
- Department of Plant Pathology, Washington State University, Prosser, WA 99350
| | - C Molnar
- Department of Plant Pathology, Washington State University, Prosser, WA 99350
| | - G Bishop
- G.S. Long Company, Union Gap, WA 98903
| | - A Johnson
- Department of Horticulture, Washington State University, Pullman, WA 99164
| | - C Frias
- Department of Horticulture, Washington State University, Pullman, WA 99164
| | - S J Harper
- Department of Plant Pathology, Washington State University, Prosser, WA 99350
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Ayvacı H, Güldür ME, Dikilitas M. Physiological and Biochemical Changes in Lucerne (Medicago sativa) Plants Infected with 'Candidatus Phytoplasma australasia'-Related Strain (16SrII-D Subgroup). THE PLANT PATHOLOGY JOURNAL 2022; 38:146-158. [PMID: 35385919 PMCID: PMC9343899 DOI: 10.5423/ppj.oa.12.2021.0189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/20/2022] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Changes in physiological and biochemical patterns in lucerne plants caused by the presence of 'Candidatus Phytoplasma australasia', which is one of the significant pathogens causing yield losses in lucerne plants, were investigated. Significant differences were evident in total chlorophyll, chlorophyll a, chlorophyll b, and protein amounts between 'Ca. Phytoplasma australasia'-positive and negative lucerne plants. Stress-related metabolites such as phenol, malondialdehyde, and proline accumulations in 'Ca. Phytoplasma australasia'-positive plants were remarkably higher than those of phytoplasma-negative plants. As a response to disease attack, phytoplasma-positive plants exhibited higher antioxidant enzymes (peroxidase and catalase) and non-enzymatic metabolite responses such as jasmonic and salicylic acids. We state that partial disease responses were revealed for the first time to breed resistant lucerne lines infected by 'Ca. Phytoplasma australasia'.
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Affiliation(s)
- Hümeyra Ayvacı
- Corresponding author: Phone) +90-531-7419201, FAX) +90-414-3183682, E-mail)
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Ahmed EA, Farrag AA, Kheder AA, Shaaban A. Effect of Phytoplasma Associated with Sesame Phyllody on Ultrastructural Modification, Physio-Biochemical Traits, Productivity and Oil Quality. PLANTS 2022; 11:plants11040477. [PMID: 35214810 PMCID: PMC8879811 DOI: 10.3390/plants11040477] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/08/2022] [Accepted: 02/08/2022] [Indexed: 11/24/2022]
Abstract
Phytoplasmas are obligate cell-wall-less plant pathogenic bacteria that infect many economically important crops, causing considerable yield losses worldwide. Very little information is known about phytoplasma–host plant interaction mechanisms and their influence on sesame yield and oil quality. Therefore, our aim was to explore the ultrastructural and agro-physio-biochemical responses of sesame plants and their effects on sesame productivity and oil quality in response to phytoplasma infection. Sesame leaf samples exhibiting phyllody symptoms were collected from three experimental fields during the 2021 growing season. Phytoplasma was successfully detected by nested- polymerase chain reaction (PCR) assays using the universal primer pairs P1/P7 and R16F2n/R16R2, and the product of approximately 1200 bp was amplified. The amplified product of 16S rRNA was sequenced and compared with other available phytoplasma’s 16S rRNA in the GenBank database. Phylogenetic analysis revealed that our Egyptian isolate under accession number MW945416 is closely related to the 16SrII group and showed close (99.7%) identity with MH011394 and L33765.1, which were isolated from Egypt and the USA, respectively. The microscopic examination of phytoplasma-infected plants revealed an observable deterioration in tissue and cell ultrastructure. The primary and secondary metabolites considerably increased in infected plants compared with healthy ones. Moreover, phytoplasma-infected plants showed drastically reduced water content, chlorophyll content, growth, and yield components, resulting in 37.9% and 42.5% reductions in seed and oil yield, respectively. The peroxide value of the infected plant’s oil was 43.2% higher than that of healthy ones, suggesting a short shelf-life. Our findings will provide a better understanding of the phyllody disease pathosystem, helping us to develop effective strategies for overcoming such diseases.
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Affiliation(s)
- Eman A. Ahmed
- Virus and Phytoplasma Research Department, Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt; (E.A.A.); (A.A.F.); (A.A.K.)
| | - Amro A. Farrag
- Virus and Phytoplasma Research Department, Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt; (E.A.A.); (A.A.F.); (A.A.K.)
| | - Ahmed A. Kheder
- Virus and Phytoplasma Research Department, Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt; (E.A.A.); (A.A.F.); (A.A.K.)
| | - Ahmed Shaaban
- Agronomy Department, Faculty of Agriculture, Fayoum University, Fayoum 63514, Egypt
- Correspondence:
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Wright AA, Shires MK, Beaver C, Bishop G, DuPont ST, Naranjo R, Harper S. Effect of ' Candidatus Phytoplasma pruni' Infection on Sweet Cherry Fruit. PHYTOPATHOLOGY 2021; 111:2195-2202. [PMID: 33961495 DOI: 10.1094/phyto-03-21-0106-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In sweet cherry (Prunus avium), infection by 'Candidatus Phytoplasma pruni' results in small fruit with poor color and taste, rendering the fruit unmarketable. Yet the disease pathology is poorly understood, particularly at the cultivar level. Therefore, in this study we examined the physiological effects of Ca. P. pruni infection across a range of cultivars and locations in eastern Washington. We found that infection could be separated into early and established stages based on pathogen titer, which correlated with disease severity, including fruit size, color, and sugar and metabolite content. Furthermore, we observed that the effects of early-stage infections were largely indistinguishable from healthy, uninfected plants. Cultivar- and location-specific disease outcomes were observed with regard to size, color, sugar content, and citric acid content. This study presents the first in-depth assessment of X-disease symptoms and biochemical content of fruit from commercially grown sweet cherry cultivars known to be infected with Ca. P. pruni.
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Affiliation(s)
- Alice Ann Wright
- Department of Plant Pathology, Washington State University, Prosser, WA 99350
| | - Madalyn K Shires
- Department of Plant Pathology, Washington State University, Prosser, WA 99350
| | - Christopher Beaver
- Viticulture and Enology, Washington State University, Richland, WA 99354
| | | | | | | | - Scott Harper
- Department of Plant Pathology, Washington State University, Prosser, WA 99350
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Abstract
Rose-scented geranium (Pelargonium sp.) have been the subject of many studies concerning essential oil, unlike the edible flowers of scent Pelargonium despite the beneficial properties of chemical compounds present in such organ and the fragrances produced. Therefore, we investigated organic compounds, total phenols and the antioxidant activity of the flowers with particular attention to the volatile compounds emitted by flowers of Pelargonium ‘Endsleigh’ at three stages of development. We identified several major phenols and organic compounds that revealed significative difference compared with other Pelargonium flowers, and employing the solid-phase micro extraction (SPME) methodology we determined that the production of volatile compounds decreases during the flower development. In addition, the emission of volatiles is accomplished mainly by the sepals. In conclusion, to use Pelargonium ‘Endsleigh’ flowers, it is important in ensuring that they have not yet opened and that the sepals are in place.
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Negro C, Aprile A, Luvisi A, De Bellis L, Miceli A. Antioxidant Activity and Polyphenols Characterization of Four Monovarietal Grape Pomaces from Salento (Apulia, Italy). Antioxidants (Basel) 2021; 10:1406. [PMID: 34573038 PMCID: PMC8465212 DOI: 10.3390/antiox10091406] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 11/24/2022] Open
Abstract
The wine industry annually produces millions of tons of by-products rich in polyphenolic compounds that can be reused as secondary raw material in the food, cosmetic and pharmaceutical industries. The purpose of this work was to describe the presence of nutraceutical compounds and to evaluate the antioxidant activity of pomaces from three Apulian (South Italy, Italy) grape varieties (Negroamaro, Malvasia di Lecce and Primitivo) and to compare them with one of the most cultivated wines in Europe (Cabernet Sauvignon). The main classes of polyphenolic substances were characterized via high performance liquid chromatography/diode array detector/mass spectrometer time of flight (HPLC/DAD/TOF) and the antioxidant activity was evaluated with three different methods. The four investigated grape marcs have shown different polyphenols and antioxidant activities. Primitivo marc showed the higher antioxidant activity due to the excellent level of polyphenols, followed by the Negroamaro cultivar. In addition, marcs from traditional Apulian vines showed higher antioxidant activities than Cabernet Sauvignon because of an elevated level of active polyphenolic substances such as catechin, epicatechin, quercetin and its derivatives.
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Affiliation(s)
- Carmine Negro
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), Salento University, 73100 Lecce, Italy; (A.A.); (A.L.); (L.D.B.); (A.M.)
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Effect of Drying Methods on Phenolic Compounds and Antioxidant Activity of Urtica dioica L. Leaves. HORTICULTURAE 2021. [DOI: 10.3390/horticulturae7010010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Stinging nettle (Urtica dioica) is a plant well known in traditional medicine for its many beneficial properties, but the lack of standardization regarding the product to offer to consumers limits its diffusion. To this end, drying appears to be a useful technique to offer a low-cost product that can be stored for long time, but the different drying procedures may give rise to end-products of very different quality as nutraceutical and antioxidant compounds. Nettle leaves have been dehydrated employing freeze-drying (FD), oven-drying (OD) or heat pump drying (HPD) and compared with fresh leaves following water extraction to emulate the use by final consumers. Results indicate that the best dehydration technique is HPD, which apparently gives rise to more than a doubling of total phenols and antioxidant activity in the extract compared to the water extract obtained from fresh leaves but a reduction in the level of ascorbic acid of about 39%. In addition, the content of some phenolic compounds is 10 to over a hundred times higher in the extract after HPD than that obtained from fresh samples. This confirms that the dehydration technique should be tuned in relation to the compounds of greatest interest or value.
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Detection of Two Different Grapevine Yellows in Vitis vinifera Using Hyperspectral Imaging. REMOTE SENSING 2020. [DOI: 10.3390/rs12244151] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Grapevine yellows (GY) are serious phytoplasma-caused diseases affecting viticultural areas worldwide. At present, two principal agents of GY are known to infest grapevines in Germany: Bois noir (BN) and Palatinate grapevine yellows (PGY). Disease management is mostly based on prophylactic measures as there are no curative in-field treatments available. In this context, sensor-based disease detection could be a useful tool for winegrowers. Therefore, hyperspectral imaging (400–2500 nm) was applied to identify phytoplasma-infected greenhouse plants and shoots collected in the field. Disease detection models (Radial-Basis Function Network) have successfully been developed for greenhouse plants of two white grapevine varieties infected with BN and PGY. Differentiation of symptomatic and healthy plants was possible reaching satisfying classification accuracies of up to 96%. However, identification of BN-infected but symptomless vines was difficult and needs further investigation. Regarding shoots collected in the field from different red and white varieties, correct classifications of up to 100% could be reached using a Multi-Layer Perceptron Network for analysis. Thus, hyperspectral imaging seems to be a promising approach for the detection of different GY. Moreover, the 10 most important wavelengths were identified for each disease detection approach, many of which could be found between 400 and 700 nm and in the short-wave infrared region (1585, 2135, and 2300 nm). These wavelengths could be used further to develop multispectral systems.
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