Papers by Samuele Moretti
Journal of Fungi
Fomitiporia mediterranea (Fmed) is the primary Basidiomycota species causing white rot in Europea... more Fomitiporia mediterranea (Fmed) is the primary Basidiomycota species causing white rot in European vineyards affected by the Esca complex of diseases (ECD). In the last few years, an increasing number of studies have highlighted the importance of reconsidering the role of Fmed in ECD etiology, justifying an increase in research interest related to Fmed’s biomolecular pathogenetic mechanisms. In the context of the current re-evaluation of the binary distinction (brown vs. white rot) between biomolecular decay pathways induced by Basidiomycota species, our research aims to investigate the potential for non-enzymatic mechanisms adopted by Fmed, which is typically described as a white rot fungus. Our results demonstrate how, in liquid culture reproducing nutrient restriction conditions often found in wood, Fmed can produce low molecular weight compounds, the hallmark of the non-enzymatic “chelator-mediated Fenton” (CMF) reaction, originally described for brown rot fungi. CMF reactions c...
Frontiers in Microbiology, 2022
Fomitiporia mediterraneais aBasidiomycetesfungus associated with some of the Esca complex disease... more Fomitiporia mediterraneais aBasidiomycetesfungus associated with some of the Esca complex diseases and responsible for decay in grapevine wood. Its role in the onset of foliar symptoms has recently been reconsidered, mainly after evidence showing a reduction in foliar symptom expression after removal of rotten wood. The study of its degradation pathways has already been approached by other authors, and with this study much information is consolidated. A microscopic observation of degraded wood provides a first approach to the characterization ofF. mediterraneamodalities of wood cellular structure degradation. The decay of grapevine wood was reproducedin vitro, and the measurement of each wood-forming polymer loss highlighted characteristics ofF. mediterraneacommon to selective white rot and showed how fungal strain and vine variety are factors determining the wood degradation. All these observations were supported by the analysis of the laccase and manganese peroxidase enzyme activi...
Frontiers in Microbiology, 2022
Grapevine trunk diseases are widespread in all grape-growing countries. The diseases included in ... more Grapevine trunk diseases are widespread in all grape-growing countries. The diseases included in the Esca complex of diseases are particularly common in European vineyards. Their distinctive foliar symptoms are well known to be associated not only with losses in quantity, as with all grapevine wood diseases, but also with losses in the quality of the crop. Protection of pruning wounds is known to reduce infections in artificial inoculations and, to some extent, reduce the external leaf symptoms. The application of biological control agents in the field is typically started at the first appearance of symptoms. In this article, the two strains belonging to two different species,Trichoderma asperellumICC 012 andT. gamsiiICC 080, which are present in a commercial formulation, were testedin vitro,in vivoin artificial inoculation, and in the field in long-term experiments where the wounds on four young asymptomatic vineyards were protected since 1 or 2 years after planting. Thein vitrotri...
Frontiers in Plant Science, 2021
Three different cDNA sequences, designated OepPDAT1-1, OepPDAT1-2, and OepPDAT2, encoding three p... more Three different cDNA sequences, designated OepPDAT1-1, OepPDAT1-2, and OepPDAT2, encoding three phospholipid:diacylglycerol acyltransferases (PDAT) have been isolated from olive (Olea europaea cv. Picual). Sequence analysis showed the distinctive features typical of the PDAT family and together with phylogenetic analysis indicated that they encode PDAT. Gene expression analysis in different olive tissues showed that transcript levels of these three PDAT genes are spatially and temporally regulated and suggested that, in addition to acyl-CoA:diacylglycerol acyltransferase, OePDAT1-1 may contribute to the biosynthesis of triacylglycerols in the seed, whereas OePDAT1-2 could be involved in the triacylglycerols content in the mesocarp and, therefore, in the olive oil. The relative contribution of PDAT and acyl-CoA:diacylglycerol acyltransferase enzymes to the triacylglycerols content in olive appears to be tissue-dependent. Furthermore, water regime, temperature, light, and wounding reg...
Journal of Fungi, 2021
In the last few years, trunk surgery has gained increasing attention as a method to reduce foliar... more In the last few years, trunk surgery has gained increasing attention as a method to reduce foliar symptoms typical of some of the Esca complex diseases. The technique relies on the mechanical removal of decayed wood by a chainsaw. A study on a 14-year-old Cabernet Sauvignon vineyard was carried out to validate the efficacy of trunk surgery and explore possible explanations behind it. Three levels of treatment were applied to three of the most characteristic symptoms associated with some diseases of the Esca complex, such as leaf stripe symptoms (LS), wilted shoots (WS) and apoplexy (APP). The most promising results were obtained by complete trunk surgery, where the larger decay removal allowed lower symptom re-expression. According to the wood types analyzed (decay, medium and sound wood), different changes in microbiota were observed. Alpha-diversity generally decreased for bacteria and increased for fungi. More specifically, main changes were observed for Fomitiporia mediterranea ...
Annual Plant Reviews online, 2021
Phytopathologia Mediterranea, 2021
Fomitiporia mediterranea M. Fisch. (Fmed) is a basidiomycete first described in 2002, and was con... more Fomitiporia mediterranea M. Fisch. (Fmed) is a basidiomycete first described in 2002, and was considered up to then as part of Fomitiporia punctata (P. Karst) Murrill. This fungus can degrade lignocellulosic biomass, causing white rot and leaving bleached fibrous host residues. In Europe Fmed is considered the main grapevine wood rot (Esca) agent within the Esca disease complex, which includes some of the most economically important Grapevine Trunk Diseases (GTDs). This review summarises and evaluates published research on Fmed, on white rot elimination by curettage or management by treatments with specific products applied to diseased grapevines, and on the relationship between wood symptoms and Grapevine Leaf Stripe Disease (GLSD) in the Esca disease complex. Information is also reviewed on the fungus biology, mechanisms of pathogenicity, and their possible relationships with external foliar symptoms of the Esca disease complex. Information on Fmed control strategies is also revie...
Tree Physiology, 2020
Xylella fastidiosa (Xf) Wells, Raju et al., 1986 is a bacterium that causes plant diseases in the... more Xylella fastidiosa (Xf) Wells, Raju et al., 1986 is a bacterium that causes plant diseases in the Americas. In Europe, it was first detected on the Salento Peninsula (Italy), where it was found to be associated with the olive quick decline syndrome. Here, we present the results of the first tree-ring study of infected and uninfected olive trees (Olea europaea L.) of two different cultivars, one resistant and one susceptible, to establish the effects induced by the spread of the pathogen inside the tree. Changes in wood anatomical characteristics, such as an increase in the number of vessels and in ring width, were observed in the infected plants of both the cultivars Cellina di Nardò (susceptible to Xf infection) and Leccino (resistant to Xf infection). Thus, whether infection affects the mortality of the tree or not, the tree shows a reaction to it. The presence of occlusions was detected in the wood of both 4-year-old branches and the tree stem core. As expected, the percentage of...
Plant Physiology and Biochemistry, 2019
The effect of salinity on physiological traits, fatty acid composition and desaturase 16 genes ex... more The effect of salinity on physiological traits, fatty acid composition and desaturase 16 genes expression in fruit mesocarp of olive cultivar Leccino was investigated. 17 Significant reduction of shoot elongation (-12%) during salt treatments (80 mM 18 NaCl) was associated with the translocation of Na in the aerial part. After 75 days 19 of treatment, fruits from each plant were subdivided into four maturation groups 20 (MG 0 , MG 1 , MG 2 , MG 3) according to ripening degrees. Na accumulation increased 21 in each MG under salinity, reaching the highest values in MG 1 fruits (2654 mg kg-1 22 DW). Salinity caused an acceleration of the ripening process, increased fruit 23 number and decreased total fatty acids content in MG 3. An increase in oleic acid at 24 MG 1 (53%) was detected, with consequent increase in the oleic/linoleic (41%) and 25 decrease in the polyunsaturated/monounsaturated ratios (30%). Those variations 26 could be explained by the synergic up-regulation of OeSAD1, together with the 27 down-regulation of OeFAD6 transcript levels. 28
Scientia Horticulturae, 2018
The effect of salinity on physiology of olive (Olea europaea L.) fruits was studied using a salt-... more The effect of salinity on physiology of olive (Olea europaea L.) fruits was studied using a salt-sensitive genotype (Leccino cv.) able to translocate sodium to the aerial part. Plants were treated with 0 and 60 mM NaCl for 49 days starting from the beginning of pit hardening to veraison. The effects of salt exposure were studied classifying olive in two Maturation Groups: MG 1 olives from green skin to < 50% purple skin; MG 2 olives with purple skin ≥50%. Plants treated with NaCl present a significant reduction of shoot elongation after 35, 42 and 49 days of salt treatment (15%, 18% and 24%, respectively). Na accumulation occurs in fruit flesh depending on the MG: 559 mg kg −1 in MG 1 and 397 mg kg −1 in MG 2. In general, NaCl does not negatively affect fruit yield parameters while induce an increment of total phenols (58%) and DPPH scavenging activity (15%) in MG 1 in comparison with control. Cryo-SEM observations of freeze-fractured fruits revealed that salt treatment induce an increment of cells area and a thickening of cuticle, epidermis, hypodermis and outer mesocarp, that could be considered useful to protect fruits against other biotic and abiotic stress.
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Papers by Samuele Moretti