Phytopathologia Mediterranea https://oajournals.fupress.net/index.php/pm <p><em>Phytopathologia Mediterranea</em> is an international open-access, peer-reviewed journal edited by the <a title="Mediterranean phytopathological union" href="http://www.unifi.it/istituzioni/mpu/" target="_blank" rel="noopener">Mediterranean Phytopathological Union</a>. The journal deals with the main areas of plant pathology as epidemiology, control, biochemical and physiological aspects, application of molecular biology techniques, applied to fungi, bacteria, phytoplasmas, viruses, viroids, nematodes, etc. Special attention is given to phytopathological problems of the Mediterranean area. The journal includes 3 issues per year in which a review paper, original research papers, short notes and new disease reports are published. It also includes Book reviews of interest for Mediterranean phytopathologists. Papers are published in English. Phytopathologia Mediterranea is covered by CAB, BIOSIS, AGRIS, Chemical Abstracts, CSA, JSTORE.</p> <p><em>Phytopathologia Mediterranea</em> is printed with the financial support of the Ministero per i Beni Culturali, Roma, Italy.</p> Firenze University Press en-US Phytopathologia Mediterranea 0031-9465 <p>Authors retain the copyright and grant the journal right of first publication with the work simultaneously licensed under a <strong>Creative Commons Attribution 4.0 International Public License (<a href="https://creativecommons.org/licenses/by/4.0/">CC-BY-4.0</a>)</strong>&nbsp;that allows others to share the work with an acknowledgment of the work's authorship and initial publication in PHYTO</p> <p><a href="http://creativecommons.org/licenses/by/4.0/" rel="license"><img style="border-width: 0;" src="https://i.creativecommons.org/l/by/4.0/88x31.png" alt="Creative Commons License"></a><br>This work is licensed under a <a href="http://creativecommons.org/licenses/by/4.0/" rel="license">Creative Commons Attribution 4.0 International License</a></p> Allexivirus: review and perspectives https://oajournals.fupress.net/index.php/pm/article/view/12043 <p class="p1"><span class="s1"><em>Allexivirus</em></span> (<span class="s1"><em>Alphaflexiviridae</em></span>) was first described in 1970 by Razvjazkina. Since then, <span class="s1"><em>Allexivirus</em></span> species have been detected in many countries. Although this genus primarily infects plants in the <span class="s1"><em>Amaryllidaceae</em></span>, other hosts include plants in the <span class="s1"><em>Fabaceae</em></span>, <span class="s1"><em>Rosaceae</em></span> and <span class="s1"><em>Orchidaceae</em></span>. Thirteen <span class="s1"><em>Allexivirus</em></span> species have been assigned. Eight of these infect <span class="s1"><em>Allium </em></span>hosts, and these include: shallot virus X (ShVX), garlic virus A (GarV-A), garlic virus B (GarV-B), garlic virus C (GarV-C), garlic virus D (GarV-D), garlic virus E (GarV-E), garlic virus X (GarV-X), and garlic-mite filamentous virus (GarMbFV). Five have been described from non-<span class="s1"><em>Allium</em></span> hosts, including blackberry virus E (BVE), vanilla latent virus (VLV), alfalfa virus S (AVS), Arachis pintoi virus (ApV), and Senna severe yellow mosaic virus (SSYMV). This review analyzes the taxonomic positions of the thirteen recognized species and four unassigned species (Allexivirus DS-2013/CZE isolate, shallot mite-borne latent virus (SMbLV), cassia mild mosaic virus (CaMMV), and papaya virus A (PaVA)). Based on the inspection of data, we have concluded that PaVA is an <span class="s1"><em>Allexivirus</em></span>, DS-2013/CZE is an isolate of GarV-D, and SMbLV is an isolate of ShVX. Current knowledge of the host ranges, symptoms, genome structure and modes of transmission of these viruses is also summarized, and control measures employed against them are outlined.</p> Faten Mansouri Pavel Ryšánek Copyright (c) 2021 Faten Mansouri, Pavel Ryšánek https://creativecommons.org/licenses/by/4.0 2021-11-15 2021-11-15 60 3 389 402 10.36253/phyto-12043 Sternbergia lutea, a new host of Narcissus late season yellows virus https://oajournals.fupress.net/index.php/pm/article/view/12709 <p class="p1">In autumn 2017, autumn daffodil plants with yellow-green stripes on the leaves were observed at a botanical garden in Budapest, Hungary. Indicator plants were inoculated, but symptoms did not develop. RT-PCR tests of the indicator plants were also negative for the viruses. <span class="s1"><em>Potyvirus</em></span> specific ACP-ELISA and RT-PCR were carried out on the symptomatic <span class="s1"><em>S. lutea</em></span> leaf samples. RT-PCR with universal potyvirus primers resulted in one, approx. 1700 base pair PCR product. Phylogenetic analysis of the nucleotide sequence of the coat protein demonstrated 98.78-99.51% identity with three Japanese isolates of <span class="s1"><em>Narcissus late season yellows virus</em></span>. While unidentified potyvirus infection of autumn daffodil has been previously reported, sequence data have not been published. Therefore, this is the first report of <span class="s1"><em>Sternbergia lutea</em></span> as a host of <span class="s1"><em>Narcissus late season yellows virus</em></span>.</p> János Ágoston Asztéria Almási Katalin Salánki László Palkovics Copyright (c) 2021 János Ágoston, Asztéria Almási, Katalin Salánki, László Palkovics https://creativecommons.org/licenses/by/4.0 2021-11-15 2021-11-15 60 3 403 407 10.36253/phyto-12709 Nightshade (Solanum nigrum), an intermediate host between tomato and cucurbits of Tomato leaf curl New Delhi virus https://oajournals.fupress.net/index.php/pm/article/view/12745 <p class="p1">Geminiviruses infect many crop plants, and are limiting factors for vegetable crop production. Begomoviruses (<span class="s1"><em>Geminiviridae</em></span>) cause typical symptoms of leaf curling and puckering in nightshade (<span class="s1"><em>Solanum nigrum</em></span>), a seasonal weed in Bihar, India. To investigate if nightshade was an intermediate host for begomovirus, virus DNA was extracted and characterized. The DNA-A of the virus yielded 2737 nt and DNA-B yielded 2706 nt. The intergenic region (IR) showed a conserved nonanucleotide sequence that potentially forms a stem-loop structure. The genomic sequence of DNA-A shared 94% identity with that of <span class="s1"><em>Tomato leaf curl New Delhi virus </em></span>(ToLCNDV)<span class="s1"><em>-</em></span>ivy gourd isolate. However, the sequence of DNA-B showed 95% identity with a bitter gourd isolate. PCR-based detection revealed the presence ToLCNDV in bottle gourd, pumpkin, sponge gourd, and bitter gourd. The IR sequences of the viruses isolated from these cucurbits and tomato were 100% identical. Whitefly-mediated transmission of the virus to cucurbits and tomato from nightshade was also demonstrated. These results indicate that nightshade may act as reservoir of ToLCNDV, and is involved in developing epidemics in cucurbit species. The strain of ToLCNDV has probably adapted from solanaceous to cucurbitaceous hosts. This is the first report of ToLCNDV infecting nightshade in India, highlighting this virus as a possible cause of disease epidemics in economically important cucurbits.</p> Mohammad Ansar Aniruddha Kumar Agnihotri Tushar Ranjan Monika Karn Srinivasaraghavan A Ravi Ranjan Kumar Arun Prasad Bhagat Copyright (c) 2021 Mohammad Ansar, Aniruddha Kumar Agnihotri, Tushar Ranjan, Monika Karn, Srinivasaraghavan A, Ravi Ranjan Kumar, Arun Prasad Bhagat https://creativecommons.org/licenses/by/4.0 2021-11-15 2021-11-15 60 3 409 419 10.36253/phyto-12745 High-density ‘Spadona’ pear orchard shows reduced tree sensitivity to fire blight damage due to decreased tree vigour https://oajournals.fupress.net/index.php/pm/article/view/12847 <p class="p1">Fire blight, caused by <span class="s1"><em>Erwinia amylovora</em></span>, is a severe disease of pear (<span class="s1"><em>Pyrus communis</em></span>). Highly vigorous trees are more sensitive to <span class="s1"><em>E. amylovora </em></span>damage after summer pruning. Trees grown in high-density orchards have lower vigour than those in low-density orchards, reducing required inputs for pruning and tying, and increasing per hectare yields orchard profitability. Tree damage due to fire blight was assessed in high-density pear orchards <span class="s1"><em>vs.</em></span> the common Israeli low-density orchards. Pear trees were planted at high densities using the spindle system (2500 trees ha<sup>-1</sup> for ‘Spadona’ and 1250 trees ha<sup>-1</sup> for ‘Coscia’), or at low density (1000 trees ha<sup>-1</sup>) using palmeta (’Spadona’) or open vase (‘Coscia’) systems. Four years after planting, both orchards were similarly infected with fire blight (11–50 infected blossoms per tree), but 1 year after infection, trees in the high density orchard had blossoms infections in the main limbs or trunk bases compared to the low-density orchard. At 3 years after initial infection, no trees had died in the high density orchard, whereas in the low density ‘Spadona’ orchard, 10% of the trees were wilted. For the more tolerant ‘Coscia’, infection did not progress at either orchard density. These results indicate that in fire blight-susceptible pear cultivars, a high density planting system, associated with reduced tree vigour, presents a decreased risk of fire blight damage.</p> Mery Dafny-Yelin Jehudith Clara Moy Raphael A. Stern Israel Doron Miriam Silberstein Daphna Michaeli Copyright (c) 2021 Mery Dafny-Yelin, Jehudith Clara Moy, Raphael A. Stern, Israel Doron, Miriam Silberstein, Daphna Michaeli https://creativecommons.org/licenses/by/4.0 2021-11-15 2021-11-15 60 3 421 426 10.36253/phyto-12847 Fungal pathogens associated with harvested table grapes in Lebanon, and characterization of the mycotoxigenic genera https://oajournals.fupress.net/index.php/pm/article/view/12946 <p class="p1">Table grapes are exposed to fungal infections before and after harvest. In particular, <span class="s1"><em>Aspergillus</em></span>,<span class="s1"><em> Penicillium</em></span>, and <span class="s1"><em>Alternaria</em></span> can cause decays and contamination by mycotoxins. The main fungi affecting Lebanese table grapes after harvest were assessed as epiphytic populations, latent infections, and rots. Effects of storage with and without SO<sub>2</sub> generating pads were also evaluated. Representative isolates of toxigenic genera were characterised, and their genetic potential to produce ochratoxin A, fumonisins, and patulin was established. The epiphytic populations mainly included wound pathogens (<span class="s1"><em>Aspergillus</em></span> spp. and <span class="s1"><em>Penicillium</em></span> spp.), while latent infections and rots were mostly caused by <span class="s1"><em>Botrytis</em></span> spp. The use of SO<sub>2</sub> generating pads reduced the epiphytic populations and rots, but was less effective against latent infections. Characterization of <span class="s1"><em>Aspergillus</em></span>, <span class="s1"><em>Penicillium,</em></span> and <span class="s1"><em>Alternaria</em></span> isolates showed that <span class="s1"><em>A. tubingensis</em></span>, <span class="s1"><em>P. glabrum,</em></span> and <span class="s1"><em>A. alternata</em></span> were the most common species. Strains of <span class="s1"><em>A. welwitschiae</em></span> and <span class="s1"><em>P. expansum</em></span> were also found to be genetically able to produce, respectively, ochratoxin A plus fumonisins and patulin. These data demonstrate the need for effective measures to prevent postharvest losses caused by toxigenic fungi.</p> Wassim Habib Jack Khalil Annamaria Mincuzzi Carine Saab Elvis Gerges Hala Chahine Tsouvalakis Antonio Ippolito Simona Marianna Sanzani Copyright (c) 2021 Wassim Habib, Jack Khalil, Annamaria Mincuzzi, Carine Saab, Elvis Gerges, Hala Chahine Tsouvalakis, Antonio Ippolito, Simona Marianna Sanzani https://creativecommons.org/licenses/by/4.0 2021-11-15 2021-11-15 60 3 427 439 10.36253/phyto-12946 Histopathological aspects of resistance in wheat to Puccinia triticina, induced by Pseudomonas protegens CHA0 and β-aminobutyric acid https://oajournals.fupress.net/index.php/pm/article/view/13123 <p class="p1">After perception of specific biotic or abiotic stimuli, such as root colonization by rhizobacteria or selected chemicals, plants can enhance their basal resistance against pathogens. Due to its likely sustainability, this induced resistance will be valuable for disease management in agriculture. This study examined resistance against wheat leaf rust (<span class="s1"><em>Puccinia triticina</em></span>) induced by <span class="s1"><em>Pseudomonas protegens</em></span> CHA0 (CHA0) and β-aminobutyric acid (BABA). Seed dressing with CHA0 reduced the number of sporulating pustules on leaves, and expression of resistance was visible as necrotic or chlorotic leaf flecks. Beneficial effect of CHA0 on wheat seedlings growth was observed in when they were challenged or not with leaf rust. BABA was tested at 10, 15 or 20 mM, and a dose-dependent reduction of leaf rust infections was observed with greatest protection at 20 mM. However, BABA treatment repressed plant growth at 20 mM. Balancing the BABA impact on plant growth and its protective capacity, 15 mM of the compound was selected as suitable to protect wheat seedlings against leaf rust, with the least impact on vegetative host growth. Histological aspects of the pathogen infection process was studied to understand mechanisms of behind the observed resistance. The pre-entry process was not affected by the two resistance inducers, but both treatments reduced fungus penetration and haustorium formation. Timing and amplitude of the resistance reactions were different after bacterial or chemical induction, leading to different levels of resistance. During fungal colonization of host tissues, high deposition of callose and accumulation of H<sub>2</sub>O<sub>2 </sub>in both CHA0- and BABA-treated plants indicated important contributions to resistance.</p> Fares Bellameche Mohammed Abbas Jasim Brigitte Mauch-Mani Fabio Mascher Copyright (c) 2021 Fares Bellameche, Mohammed Abbas Jasim, Brigitte Mauch-Mani, Fabio Mascher https://creativecommons.org/licenses/by/4.0 2021-11-15 2021-11-15 60 3 441 453 10.36253/phyto-13123 Assessment of weed root extracts for allelopathic activity against Orobanche and Phelipanche species https://oajournals.fupress.net/index.php/pm/article/view/12917 <p class="p1">Broomrapes (<em>Orobanche</em> and <em>Phelipanche</em> species) are holoparasitic weeds that infect roots of crop hosts from Asteraceae, Brassicaceae, Apiaceae, Fabaceae, and Solanaceae. The parasitic weeds are difficult to control selectively without crop damage once attached to their roots. Identification of natural compounds with herbicidal activity against pre-attached broomrape stages can provide control alternatives. With the aim to identify plant species with efficacy for broomrape control, organic and residual aqueous phase extracts from roots of seventeen weed species common in south Spanish broomrape-infested fields were assessed as potential inducers of suicidal broomrape germination and as inhibitors of broomrape radicle growth. Assessments were carried out <em>in vitro</em> using seeds and seedlings of four noxious broomrape species, <em>Orobanche crenata</em> Forsk<em>.</em>, <em>Orobanche cumana </em>Wallr., <em>Orobanche minor</em> Sm. and <em>Phelipanche ramosa </em>(L.) Pomel. While root extracts from all the weed species did not induce suicidal germination on <em>O. crenata</em> seeds, most of the extracts induced germination of <em>P. ramosa</em> except for those obtained from <em>Amaranthus albus</em> L., <em>Amaranthus retroflexus</em> L. and <em>Convolvulus arvensis </em>L. Moderate levels of germination activity were induced in <em>O. cumana</em> and <em>O. minor</em> seeds by some of the root extracts tested, with strongest induction obtained from <em>Heliotropium europaeum </em>L. on <em>O. cumana</em> seeds, and from <em>Silybum marianum </em>(L.) Gaertn<em>. </em>on <em>O. minor</em> seeds. For root extract inhibition of broomrape radicles, the extract from <em>C. arvensis</em> roots strongly inhibited radicles of all the broomrape species. While extracts from the other weed species induced low or negligible inhibition of <em>O. cumana</em> and <em>O. crenata</em> radicle growth, many inhibited <em>P. ramosa</em> and <em>O. minor</em> radicles. Exceptions were root extracts from <em>Datura stramonium </em>L., <em>Heliotropium europaeum </em>L., <em>Malva sylvestris </em>L., <em>Solanum nigrum</em> L. and <em>Urtica dioica</em> L., which did not inhibit <em>P. ramosa</em> radicles, and those from <em>A. retroflexus</em>, <em>Datura stramonium </em>L., <em>Malva sylvestris </em>L., <em>Portulaca oleracea</em> L. and <em>S. nigrum</em>, which did not inhibit <em>O. minor</em> radicles. Among the active organic extracts assessed, those showing promising chemical profiles were selected for future studies to characterize natural compounds with potential herbicidal activity on early stages of broomrape growth.</p> Mónica Fernández-Aparicio Alessio Cimmino Gabriele Soriano Marco Masi Susana Vilariño Antonio Evidente Copyright (c) 2021 Mónica Fernández-Aparicio, Alessio Cimmino, Gabriele Soriano, Marco Masi, Susana Vilariño, Antonio Evidente https://creativecommons.org/licenses/by/4.0 2021-12-30 2021-12-30 60 3 455 466 10.36253/phyto-12917 Dissemination of esca-related pathogens in German vineyards: do arthropods play roles in vectoring spores? https://oajournals.fupress.net/index.php/pm/article/view/12948 <p class="p1"><span class="s1">Grapevine Trunk Diseases (GTDs) such as esca challenge viticulture. The main fungal agents of Petri disease or young esca, <em>Phaeomoniella</em>&nbsp;<em>chlamydospora</em> (<em>Pch</em>), diverse <em>Phaeoacremonium</em> species (<em>Pm</em> spp.) and <em>Cadophora</em>&nbsp;<em>luteo-olivacea</em> (<em>Clo</em>), are transmitted to pruning wounds of vines by rain splashes and air currents. Arthropod-mediated dispersal is another possibility for the pathogens to reach pruning wounds. The present study was the first to evaluate possible involvement of arthropods in the dissemination process of esca-related pathogens in German vineyards. Diversity of arthropods on grapevine trunks was determined in 2019 and 2020, using cardboard traps mounted on vine trunks. Captured arthropods were surveyed for the presence of esca-related pathogens on their exoskeletons by using a nested multiplex PCR. In total, 2099 arthropods were examined, of which 35% were positive for <em>Phaeomoniella chlamydospora</em> (<em>Pch</em>), 21% for <em>Phaeoacremonium</em> spp. (<em>Pm</em>), and 7% for <em>Cadophora luteo-olivacea</em> (<em>Clo</em>). Earwigs and spiders were the most prevalent trapped arthropods; <em>Pch</em> was detected on 27% of earwigs and 38% of spiders, <em>Pm</em> spp. on 17 and 19%, and <em>Clo</em> on 3 and 8% of these arthropods. In both years, arthropods carrying the pathogens were already present in April, and therefore within the presumed susceptibility phase of pruned vines. These results indicate involvement of arthropods in the dispersal of esca-related pathogens in German vineyards. Further research, particularly to determine the infection potential of insect-borne fungi, is needed to confirm transmission risk. These results underline the importance of protecting vine pruning wounds to prevent host invasion by GTD pathogens.</span></p> Elisa Maria Kalvelage Ralf Thomas Voegele Michael Fischer Copyright (c) 2021 Elisa Maria Kalvelage, Ralf Thomas Voegele, Michael Fischer https://creativecommons.org/licenses/by/4.0 2021-12-30 2021-12-30 60 3 467 478 10.36253/phyto-12948 Leaf anthracnose and defoliation of blueberry caused by Colletotrichum helleniense in Northern Italy https://oajournals.fupress.net/index.php/pm/article/view/12377 <p class="p1">Highbush blueberry is an increasingly important crop due to its economic value and demonstrated health benefits of blueberries. Leaf spots are considered as minor diseases of blueberry plants, but they adversely affect blueberry productivity, causing reduced photosynthetic activity, flower bud formation and berry production. Surveys of blueberry crops were conducted in Piedmont, Northern Italy, during 2019-2020. Fungi isolated from leaf spots of the blueberry cultivar ‘Blue Ribbon’ were identified as <em>Colletotrichum helleniense</em> through a robust multi-locus phylogeny. Eight genomic loci were considered: <em>tub</em>, <em>gapdh</em>,<em> act</em>, <em>cal</em>, <em>his3</em>, <em>chs-1</em>, <em>ApMat</em> and <em>gs</em>. Morphological characters of a representative strain were assessed. Pathogenicity was confirmed on four blueberry cultivars, although with different levels of aggressiveness to the cultivars. This study shows the importance of a polyphasic approach to investigate species of <em>Colletotrichum</em>, and the relevance of molecular tools for the species-level characterization within the ‘Kahawae’ clade. This is the first report of <em>Colletotrichum helleniense </em>causing leaf anthracnose on <em>Vaccinium corymbosum</em>.</p> Vladimiro Guarnaccia ilaria Martino Luca Brondino Angelo Garibaldi Maria Lodovica Gullino Copyright (c) 2021 Vladimiro Guarnaccia, ilaria Martino, Luca Brondino, Angelo Garibaldi, Maria Lodovica Gullino https://creativecommons.org/licenses/by/4.0 2021-12-30 2021-12-30 60 3 479 491 10.36253/phyto-12377 Viruses of cucurbit crops: current status in the Mediterranean Region https://oajournals.fupress.net/index.php/pm/article/view/12340 <p class="p1">Cucurbits are among the most cultivated crops, and the most economically important species are melon (<em>Cucumis melo</em> L.), cucumber (<em>Cucumis sativus</em> L.), watermelon (<em>Citrullus lanatus</em> Thumb.), squash (<em>Cucurbita pepo</em> L.), and pumpkin (<em>Cucurbita </em>spp.). These crops have become important income sources providing export and local consumption commodities in many Mediterranean countries. Increased area of cucurbits has led to the emergence of several viral diseases, which can have impacts on crop production and threaten agricultural sustainability. An overview of the most damaging cucurbit viruses in the Mediterranean area is provided to improve understanding of the diseases they cause and to emphasize effective disease management strategies. An updating of the geographical distribution of these viruses, the symptoms they cause and their means of transmission is also provided. Disease management methods and measures by farmers and phytosanitary authorities to address the virus outbreaks are outlined, including diagnostics, use of tolerant cultivars, and chemical and biological vector control. Mediterranean region farmers have learned many lessons from the damaging pandemics caused by cucurbit viruses, through the extensive published research, and this review provides a basis for managing future outbreaks of newly emerging virus infections.</p> Nabil Radouane Said Ezrari Zineb Belabess Abdessalem Tahiri Rachid Tahzima Sebastien Massart Haissam Jijakli Meryem Benjelloun Rachid Lahlali Copyright (c) 2021 Nabil Radouane, Said Ezrari, Zineb Belabess, Abdessalem Tahiri, Rachid Tahzima, Sebastien Massart, Haissam Jijakli, Meryem Benjelloun, Rachid Lahlali https://creativecommons.org/licenses/by/4.0 2021-12-30 2021-12-30 60 3 493 519 10.36253/phyto-12340 The distribution of Phytophthora cinnamomi in the Americas is related to its main host (Persea americana), but with high potential for expansion https://oajournals.fupress.net/index.php/pm/article/view/12327 <p class="p1"><span class="s1"><em>Phytophthora cinnamomi </em>is among the most destructive plant pathogens that affect many host plants in different ecosystems. Economically important hosts of this pathogen include avocado (<em>Persea americana</em>), and this oomycete may cause large-scale destructive epidemics. This study analyzed the potential geographic distribution of <em>P. cinnamomi </em>(pathogen) and avocado (host), and distribution of the pathogen in relation to multiple hosts in the Americas. Niche overlap between hosts and pathogen were also evaluated, using a multistep process of ecological niche modelling and the MaxEnt algorithm. Niche similarity among pathogen populations in different hosts and related niche similarity were also examined. As a complement, a tool was designed to visualize the risk of this pathogen in avocado. Results showed that the pathogen was randomly distributed in the avocado niche environmental space, but the niche of the pathogenwas narrower than<span class="Apple-converted-space">&nbsp; </span>that of its principal host. The niche of the pathogen was largely a function of the host niches. Areas with potential to grow avocado could present low risk of <em>P. cinnamomi</em>, but given the invasiveness of this pathogen, they may be affected in the future.</span></p> Joaquín Guillermo Ramírez-Gil Juan Gonzalo Morales-Osorio A. Townsend Peterson Copyright (c) 2021 Joaquín Guillermo Ramírez-Gil, Juan Gonzalo Morales-Osorio , A. Townsend Peterson https://creativecommons.org/licenses/by/4.0 2021-12-30 2021-12-30 60 3 521 534 10.36253/phyto-12327 In vitro evaluation of grapevine endophytes, epiphytes and sap micro-organisms for potential use to control grapevine trunk disease pathogens https://oajournals.fupress.net/index.php/pm/article/view/12500 <p class="p1">Grapevine trunk diseases (GTDs) threaten the economic sustainability of viticulture, causing reductions of yield and quality of grapes. Biological control is a promising sustainable alternative to cultural and chemical methods to mitigate the effects of pathogens causing GTDs, including Botryosphaeria dieback, Eutypa dieback and Esca. This study aimed to identify naturally occurring potential biological control agents from grapevine sap, cane and pith tissues, and evaluate their <em>in vitro</em> antagonistic activity against selected fungal GTD pathogens. Bacterial and fungal isolates were preliminarily screened in dual culture assays to determine their antifungal activity against <em>Neofusicoccum parvum</em> and <em>Eutypa lata</em>. Among the fungal isolates, <em>Trichoderma </em>spp. inhibited mycelium growth of <em>E. lata</em> by up to 64% and of <em>N. parvum</em> by up to 73%, with overgrowth and growth cessation being the likely antagonistic mechanisms. Among the bacterial isolates, <em>Bacillus</em> spp. inhibited mycelium growth of <em>E. lata</em> by up to 20% and of <em>N. parvum</em> by up to 40%. Selected antagonistic isolates of <em>Trichoderma, Bacillus </em>and<em> Aureobasidium</em> spp<em>.</em> were subjected to further dual culture antifungal analyses against <em>Diplodia seriata</em> and <em>Diaporthe ampelina, </em>with <em>Trichoderma</em> isolates consistently causing the greatest inhibition. Volatile organic compound antifungal analyses showed that these <em>Trichoderma</em> isolates inhibited mycelium growth of <em>N. parvum</em> (20% inhibition)<em>, E</em>. <em>lata</em> (61% inhibition) and <em>Dia. ampelina</em> (71% inhibition). Multilocus sequence analyses revealed that the <em>Trichoderma</em> isolates were most closely related to <em>Trichoderma asperellum</em> and <em>Trichoderma hamatum</em>. This study had identified grapevine sap as a novel source of potential biological control agents for control of GTDs. Further testing will be necessary to fully characterize modes of antagonism of these microorganisms, and assess their efficacy for pruning wound protection <em>in planta</em>.</p> Robert Blundell Molly Arreguin Akif Eskalen Copyright (c) 2021 Robert Blundell, Molly Arreguin, Akif Eskalen https://creativecommons.org/licenses/by/4.0 2021-12-30 2021-12-30 60 3 535 548 10.36253/phyto-12500 Structure analysis of the ribosomal intergenic spacer region of Phaeoacremonium italicum as a study model https://oajournals.fupress.net/index.php/pm/article/view/13159 <p class="p1">Increasing recognition of novel <em>Phaeoacremonium</em> species, and their recent taxonomic reassignment through phylogeny based on the β-tubulin and actin genes, have highlighted the presence of paraphyly, intraspecific variation, and incongruence of some <em>Phaeoacremonium</em> species. This study investigated the intergenic spacer rDNA regions of a representative collection of 31 <em>Phaeoacremonium</em> <em>italicum </em>strains, and compared their structures with those of the closest related species, <em>Phaeoacremonium</em> <em>alvesii</em> and <em>Phaeoacremonium</em> <em>rubrigenum</em>. These intergenic spacer sequences had five categories of repeat elements that were organised into distinct patterns. Morphological analyses of the <em>P. italicum</em> strains provided a more detailed description of <em>P. italicum</em>. The phylogenetic tree constructed using the intergenic spacer sequences compared with that obtained by combined analysis of β-tubulin and actin sequences indicated that the intergenic spacer rDNA region distinguished intraspecific and interspecific variations. Further molecular studies are required to determine whether intergenic spacer sequences can improve precision in defining <em>Phaeoacremonium</em> phylogeny, and prevent misidentification and the introduction of vague species boundaries for the genus.</p> Meriem Laidani Maria Luisa Raimondo Anna Maria D'Onghia Antonia Carlucci Copyright (c) 2021 Meriem Laidani, Maria Luisa Raimondo, Anna Maria D'Onghia, Antonia Carlucci https://creativecommons.org/licenses/by/4.0 2021-12-30 2021-12-30 60 3 549 570 10.36253/phyto-13159