Search results for "Dieback"
showing 10 items of 10 documents
Metabolites produced by agents of dieback of grapevine in Sicily: Lasiodiplodia mediterranea, Neofusicoccum parvum and N. vitifusiforme
2015
Botryosphaeria dieback was recently reported in West Sicilian vineyards. The disease complex was only associated with isolates of genus Lasiodiplodia in 2007 and together with Diplodia seriata, Neofusicoccum parvum and Neofusicoccum vitifusiforme, this latest reported for the first time on Vitis vinifera in Italy. Moreover, a representative isolate of each species was inoculated on green shoots and fulfilled Koch’s postulates, although the lengths of vascular discolourations were variable depending on the species. As well as the other GTD causal agents, the expression of foliar symptoms (pale colour along the margins and between veins) was also occasional in Sicily, it was hypothesized that…
First report of Diplodia africana on Grevillea robusta
2020
Branch cankers and dieback were observed on silky-oak trees (Grevillea robusta) along some streets of Palermo (Sicily, Italy). Fungi isolated from symptomatic branches were identified as Diplodia africana and D. seriata by morphological characters and phylogenetic analyses of combined ITS and translation elongation factor 1-α sequences. Pathogenicity was verified by inoculating twigs of 3-y-old silky-oak plants. This is the first report of D. africana on G. robusta and the first record of D. seriata on this host in the northern hemisphere.
Pathogenicity and possible biological control of fungi associated to Botryosphaeria dieback of grapevine in Western Sicily
2018
Botryosphaeria dieback is a widespread grapevine trunk disease caused by species of fungi within the family Botryosphaeriaceae. Symptoms of the disease include bud necrosis, leaf chlorosis, vascular discoloration of the wood, cankers and dieback. In 2013 typical symptoms of Botryosphaeria dieback was observed in Western Sicily and four species associated with the syndrome were isolated and identified as Diplodia seriata, Lasiodiplodia mediterranea, Neofusicoccum parvum and Neofusicoccum vitifusiforme. In order to fulfill Koch’s postulates, pathogenicity tests of eighteen isolates were performed on two-year grapevine cuttings of cv. Inzolia. Six months after inoculation all the Botryosphaeri…
Effect of methyl jasmonate in gene expression, and in hormonal and phenolic profiles of holm oak embryogenic lines before and after infection with Ph…
2022
The dieback syndrome affecting Quercus ilex and other oak species impels the search for tolerant plant genotypes, as well as methods of plant immunization against such infections. Elicitation treatments can be an effective strategy to activate plant defense response and embryogenic lines represent a promising tool to generate new tolerant genotypes and also to study early markers involved in defense response. The aim of the presented work was to investigate changes in gene expression, and in hormonal and phenolic profiles induced in three holm oak embryogenic lines (ELs) elicited with methyl jasmonate (MeJA) before and after infection with the oomycete Phytophthora cinnamomi, which is the m…
Climate-growth relationships of Quercus gussonei (Borzì) Brullo in the Mediterranean region: adaptive traits and water use efficiency.
2016
Due to their marginal distribution, peripheral tree populations are highly vulnerable and are more likely to be influenced by extreme climate conditions. This occurrence is known to cause dieback in many species at their Mediterranean margins. Quercus gussonei (Borzì) Brullo is a deciduous oak endemic of Sicily. It is a thermophilous, peripheral form of Quercus cerris L. which is showing an incipient but ongoing decline. A deeper ecophysiological knowledge is urgently needed on this species in order to plan proper conservation actions and reduce the risk of its extinction. In the aim to understand at what extent changes in environmental conditions could be responsible for Q. gussonei declin…
Lasiolactols A and B Produced by the Grapevine Fungal Pathogen Lasiodiplodia mediterranea
2016
A strain of Lasiodiplodia mediterranea, a fungus associated with grapevine decline in Sicily, produced several metabolites in liquid medium. Two new dimeric c-lactols, lasiolactols A and B (1 and 2), were characterized as (2S*,3S*,4R*,5R*,20S*,30S*,40R*,50R*)-and (2R*,3S*,4R*,5R*,20R*,30S*,40R*,50R*)-(5-(4-hydroxymethyl-3,5-dimethyl-tetrahydrofuran- 2-yloxy)-2,4-dimethyl-tetrahydro-furan-3-yl]-methanols by IR, 1D-and 2D-NMR, and HR-ESI-MS. Other four metabolites were identified as botryosphaeriodiplodin, (5R)-5-hydroxylasiodiplodin, (-)-(1R, 2R)-jasmonic acid, and (-)-(3S, 4R, 5R)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone (3 - 6, resp.). The absolute configuration (R) at hydroxylated s…
Taxonomy, pathogenicity and phylogeny of fungi associated with Botryosphaeria dieback in Sicily
2015
Since the first report of “Botryosphaeria dieback” caused by Lasiodiplodia theobromae in 2008, other Botryosphaeriaceae were found associated with declining vines in grape-growing areas of Western and Central Sicily. In a recent study, Diplodia seriata, Lasiodiplodia sp., Neofusicoccum parvum and Neofusicoccum vitifusiforme were isolated from declining grapevines. In order to fulfill Koch’s postulates and verify any genetic variability among isolates, pathogenicity, morphological, molecular and phylogenetic analyses were performed. The pathogenicity of eighteen isolates was tested by inoculating 2-year-old rooted grapevine cuttings (cv. Inzolia) and evaluating vascular discoloration length …
Les maladies du bois de la vigne : recherches pour apporter des solutions de lutte aux Professionnels
2017
Les travaux réalisés sur deux maladies du bois de la vigne (esca, BDA) ont montré leur effet sur la récolte et la croissance de la pousse printanière qui était annulé deux années après l’apparition des symptômes. Ces maladies ont aussi conduit à des modifications des propriétés analytiques des moûts et des vins. Les vins issus de raisins collectés sur des ceps symptomatiques n’étaient pas toujours les plus dépréciés. Les études effectuées sur le cycle biologique ont permis de mettre au point des outils pour différencier les individus de deux espèces de Botryosphaeriaceae et des outils d’hybridation in situ qui permettront de les localiser précisément dans les tissus. Elles ont aussi identif…