https://oajournals.fupress.net/index.php/pm/issue/feed Phytopathologia Mediterranea 2021-05-20T09:12:22+00:00 Editorial Office phymed@unifi.it Open Journal Systems <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> https://oajournals.fupress.net/index.php/pm/article/view/11616 Mating type distribution, genetic diversity and population structure of Ascochyta rabiei, the cause of Ascochyta blight of chickpea in western Iran 2021-05-17T16:53:42+00:00 Somayeh FARAHANI null@null.com Reza TALEBI srtalebi@yahoo.com Mojdeh MALEKI mojdehmaleki@yahoo.com Rahim MEHRABI null@null.com Homayoun KANOUNI null@null.com <p class="p1"><span class="s1">Ascochyta blight (caused by </span><span class="s2">Ascochyta rabiei</span><span class="s1">) is an important disease of chickpea. Mating type distribution, genetic diversity and population structure </span><span class="s2">A. rabiei</span><span class="s1"> isolates from western Iran, using specific matting type primers, and ISSR and SSR molecular markers. Two mating types were identified, with the 57% of isolates belonging to MAT1-1. Ten ISSR markers produced 78 polymorphic bands with an average polymorphism information content (PIC) value of 0.33. Seven SSR markers showed high allelic variation (four to seven alleles) with the average PIC value of 0.61. The generated dendrogram using neighbor joining approach with ISSR and SSR marker data grouped isolates in three clusters. Combined dendrogram and model-based population structure analysis divided the isolates into two distinct populations. No significant correlation was found between geographical origins of isolates and their genetic diversity patterns, although the isolates from North Kermanshah and Kurdistan were closely grouped, and most of isolates from Lorestan and Kermanshah were clustered in a separate group. This relative spatial correlation between geographical locations and </span><span class="s2">A. rabiei</span><span class="s1"> grouping indicated high genetic diversity within populations and no significant gene flow between distinctly geographical regions. This suggests the nece0ssity of continuous monitoring of </span><span class="s2">A. rabiei</span><span class="s1"> populations in order to design effective chickpea breeding strategies to control the disease.</span></p> 2021-05-13T10:48:03+00:00 Copyright (c) 2021 S. Farahani, R. Talebi, Mojdeh Maleki, R. Mehrabi, H. Kanouni https://oajournals.fupress.net/index.php/pm/article/view/11840 Characterization of two Cucumber mosaic virus isolates infecting Allium cepa in Turkey 2021-05-17T07:51:18+00:00 Adyatma I. SANTOSA adyatma_santosa@yahoo.com Filiz ERTUNC ertunc@agri.ankara.edu.tr <p class="p1"><span class="s1">Cucumber mosaic virus</span> (CMV) is polyphagous, infecting plants in several families. CMV has occurred as a minor pathogen in <span class="s1">Allium</span> crops in several Mediterranean countries, but little was known of the virus naturally infecting <span class="s1">Allium</span> spp. This study completed molecular and biological characterization of CMV-14.3Po and CMV-15.5Po, two newly identified CMV isolates infecting onion (<span class="s1">Allium cepa</span> L.) in Turkey. Phylogenetic, and nucleotide and amino acid sequence identity analyses of partial RNA2 and RNA3 of the two isolates showed that they were very similar to other CMV isolates from Mediterranean, European, and East Asian countries. Phylogenetic analysis of the partial sequence of RNA3 also showed that the onion isolates belong to subgroup IA. Onion isolates were mechanically transmissible, and caused mild leaf malformation on onion, severe leaf malformation and stunting on garlic (<span class="s1">Allium sativus</span> L.), and mosaic and mottle on cucumber (<span class="s1">Cucumis sativus</span> L.) and melon (<span class="s1">Cucumis melo</span> L.).</p> 2021-05-13T10:48:51+00:00 Copyright (c) 2021 Adyatma Irawan Santosa, Filiz Ertunc https://oajournals.fupress.net/index.php/pm/article/view/11732 Antibacterial activity of tannins towards Pseudomonas syringae pv. tomato, and their potential as biostimulants on tomato plants 2021-05-20T09:12:22+00:00 Paolo CANZONIERE canzonierepaolo@gmail.com Sara FRANCESCONI francesconi.s@unitus.it Samuele GIOVANDO sgiovando@silvateam.com Giorgio BALESTRA balestra@unitus.it <p class="p1"><span class="s1">Pseudomonas syringae</span><span class="s2"> pv. </span><span class="s1">tomato</span><span class="s2"> (Pst), the causal agent of bacterial speck of tomato, is a significant cause of economic losses in tomato crops. This disease is mainly controlled with preventive use of cupric salt formulations. Antibacterial activity of the tannins U1, U2, U3 and U4, applied alone at 1% w/v concentration or in combination with half (0.045% w/v) of standard of copper hydroxide treatments, was assayed for effects on Pst. </span><span class="s1">In vitro</span><span class="s2">, the four tannins completely inhibited Pst colony formation after 24 h, but U2 (quebracho tannins) + ½ Cu(OH)<sub>2 </sub>allowed Pst growth after 48 h of incubation, indicating that, since U2 is composed of high molecular condensed tannins it is likely that their structures have chelated the copper hydroxide much more then hydrolysable ones, thus inactivating copper hydroxide and tannins. In fact, this activity of the tannins was equivalent to that for 0.045% w/v of copper hydroxide. Effects of tannins on tomato plant growth were also assessed. On seedlings, long-term U1 treatments increased dry weight of shoots compared to copper hydroxide, but not to water treatment. The U4 treatment increased the NBI values compared to copper treatment but did not show significant differences compared to the water treatment. Inhibitory activity of tannin treatments reduced disease by 37–62%, and 60% after copper treatment, while disease severity was reduced by 33–54% after treating plants with tannins and 36% after copper treatment. On mature plants treated once, the disease reduction was 27–39% after tannin treatments and 44% after copper treatment, while severity was reduced by 50–60% from tannin treatments, and 47% by copper. In seedlings and mature plants, these reductions were similar (</span><span class="s1">P</span><span class="s2"> &gt; 0.05) for the tannins and copper treatments. This study indicates a novel crop protection strategy using natural products as alternatives to xenobiotic compounds.</span></p> 2021-05-13T10:55:13+00:00 Copyright (c) 2021 P. Canzoniere, S. Francesconi, S. Giovando, G. M. Balestra https://oajournals.fupress.net/index.php/pm/article/view/11976 Infection of papaya (Carica papaya) by four powdery mildew fungi 2021-05-17T07:50:49+00:00 Diána SERESS seress.diana@agrar.mta.hu Gábor M. KOVÁCS gmkovacs@caesar.elte.hu Orsolya MOLNÁR molnar.orsolya@agrar.mta.hu Márk Z. NÉMETH nemeth.mark@agrar.mta.hu <p class="p1">Papaya (<span class="s1">Carica papaya </span>L.) is an important fruit crop in many tropical and subtropical countries. Powdery mildew commonly affects this host, causing premature leaf loss, reduced yields and poor fruit quality. At least fifteen different fungi have been identified as the causal agents of papaya powdery mildew. Powdery mildew symptoms were detected on potted papaya plants growing in two locations in Hungary. This study aimed to identify the causal agents. Morphology of powdery mildew samples was examined, and sequences of two loci were used for molecular taxonomic identifications. Only anamophs were detected in all samples, and four morphological types were distinguished. Most samples had <span class="s1">Pseudoidium</span> anamorphs, while some were of the <span class="s1">Fibroidium</span> anamorph. Based on morphology and molecular taxonomy, the <span class="s1">Fibroidium</span> anamorph<span class="Apple-converted-space">&nbsp; </span>was identified as <span class="s1">Podosphaera xanthii.</span> The <span class="s1">Pseudoidium</span> anamorphs corresponded to three different <span class="s1">Erysiphe</span> species: <span class="s1">E. cruciferarum</span>, <span class="s1">E. necator</span> and an unidentified <span class="s1">Erysiphe</span> sp., for which molecular phylogenetic analyses showed it belonged to an unresolved species complex of <span class="s1">E. malvae</span>, <span class="s1">E. heraclei</span> and <span class="s1">E. betae.</span> Infectivity of <span class="s1">P. xanthii</span> and <span class="s1">E. necator</span> on papaya was verified with cross inoculations. A review of previous records of powdery mildew fungi infecting papaya is also provided. <span class="s1">Podosphaera xanthii</span> was known to infect, and <span class="s1">E. cruciferarum</span> was suspected to infect<span class="s1"> Carica papaya</span>, while <span class="s1">E.&nbsp;necator</span> was recorded on this host only once previously. No powdery mildew fungus belonging to the <span class="s1">E.&nbsp;malvae</span>/<span class="s1">E. heraclei</span>/<span class="s1">E. betae</span> species complex is known to infect papaya or any other plants in the Caricaceae, so the unidentified <span class="s1">Erysiphe</span> sp. is a new record on papaya and the Caricaceae. This study indicates host range expansion of this powdery mildew fungus onto papaya.</p> 2021-05-13T11:01:08+00:00 Copyright (c) 2021 Diána Seress, Gábor Kovács M., Orsolya Molnár, Márk Z. Németh https://oajournals.fupress.net/index.php/pm/article/view/11726 Characterization of Xanthomonas campestris pv. campestris in Algeria 2021-05-17T07:50:37+00:00 Samia LAALA slaala@hotmail.com Sophie CESBRON sophie.cesbron@inrae.fr Mohamed KERKOUD 123kerkoud@gmail.com Franco VALENTINI valentini@iamb.it Zouaoui BOUZNAD z.bouznad@ensa.dz Marie-Agnès JACQUES marie-agnes.jacques@inrae.fr Charles MANCEAU charlesrene.manceau@gmail.com <p class="p1"><span class="s1">Xanthomonas campestris </span>pv. <span class="s1">campestris </span>(<span class="s1">Xcc</span>) causes the black rot of cruciferous plants. This seed-borne bacterium is considered as the most destructive disease to cruciferous crops. Although sources of contamination are various, seeds are the main source of transmission. Typical symptoms of black rot were first observed in 2011 on cabbage and cauliflower fields in the main production areas of Algeria. Leaf samples displaying typical symptoms were collected during 2011 to 2014, and 170 strains were isolated from 45 commercial fields. <span class="s1">Xcc </span>isolates were very homogeneous in morphological, physiological and biochemical characteristics similar to reference strains, and gave positive pathogenicity and molecular test results (multiplex PCR with specific primers). This is the first record of <span class="s1">Xcc </span>in Algeria. Genetic diversity within the isolates was assessed in comparison with strains isolated elsewhere. A multilocus sequence analysis based on two housekeeping genes (<span class="s1">gyrB</span> and <span class="s1">rpoD</span>) was carried out on 77 strains representative isolates. The isolates grouped into 20 haplotypes defined with 68 polymorphic sites. The phylogenetic tree obtained showed that <span class="s1">Xcc</span> is in two groups, and all Algerian strains clustered in group 1 in three subgroups. No relationships were detected between haplotypes and the origins of the seed lots, the varieties of host cabbage, the years of isolation and agroclimatic regions.</p> 2021-05-13T16:32:48+00:00 Copyright (c) 2021 S. Laala, S. Cesbron, M. Kerkoud, F. Valentini, Z. Bouznad, M.-A. Jacques, C. Manceau https://oajournals.fupress.net/index.php/pm/article/view/11066 Molecular detection and identification of a ‘Candidatus Phytoplasma solani’-related strain associated with pumpkin witches’ broom in Xinjiang, China 2021-05-17T16:55:47+00:00 Xu WANG wx_xhl@163.com Chun-Guang WANG jdwcg@imau.edu.cn Xiao-Yan LI lxywqx@163.com Zheng-Nan LI lizhengnan@imau.edu.cn <p class="p1">Pumpkin plants showing symptoms of witches’ broom (PuWB) were observed in Xinjiang Uyghur autonomous region, China, in September 2018. A phytoplasma was detected in symptomatic plants by PCR amplifying portions of the 16S ribosomal and <span class="s1">tuf</span> genes. In addition, the phylogeny based on these genes sequencing indicated that the PuWB strain clusters with ‘<span class="s1">Candidatus</span> Phytoplasma solani’ (subgroup 16SrXII-A). Furthermore, based on <span class="s1">in silico</span> and <span class="s1">in vitro</span> restriction fragment length polymorphism analyses, the PuWB phytoplasma was confirmed as a ‘<span class="s1">Ca.</span> P. solani’-related strain. This was the first record of the occurrence of phytoplasma presence in pumpkins in China, and the first record of 16SrXII phytoplasma infecting pumpkins in the world.</p> 2021-05-13T00:00:00+00:00 Copyright (c) 2021 Xu WANG, Chun-Guang WANG, Xiao-Yan LI, Zheng-Nan LI https://oajournals.fupress.net/index.php/pm/article/view/10723 Reduced fitness cost and increased aggressiveness in fenhexamid-resistant Botrytis cinerea field isolates from Chile 2021-05-17T07:50:24+00:00 Marcela ESTERIO mesterio@uchile.cl Claudio OSORIO-NAVARRO anduin@ug.uchile.cl Madelaine AZÓCAR madelaine.azocar@ug.uchile.cl Charleen COPIER c.copier.a@gmail.com Mauricio RUBILAR mrubilar@gmail.com Lorena PIZARRO lorepizaro@gmail.com Jaime AUGER jauger92@gmail.com <p class="p1">Disease management programmes in Chilean table grape vineyards use the hydroxyanilide fenhexamid as a pivotal fungicide for <span class="s1">Botrytis cinerea</span> control. However, fenhexamid-resistant populations of this pathogen have progressively increased in vineyards under fungicide use. <span class="s1">Botrytis cinerea</span> isolates were collected in ‘Thompson Seedless’ vineyards under fenhexamid control programmes (&gt;two sprays per season) from three regions of Central Chile, during the 2013-2014, 2014-2015 and 2015-2016 growing seasons. Focusing on the 2015-2016 growing season when the greatest level of resistance was measured, only 8% of recovered isolates were sensitive to fenhexamid with 92% of isolates exceeding the sensitivity threshold for mycelium growth. All fenhexamid resistant isolates analyzed carried a mutation in the <span class="s1">Erg27 </span>gene, which encodes for 3-keto reductase (3-KR) enzyme. The largest proportion of isolates presented a single-point mutation, leading to a substitution of phenylalanine by serine or isoleucine in the 412 residue of 3-KR (<span class="s1">erg27</span><sup>F412S</sup>, 27%; <span class="s1">erg27</span><sup>F412I</sup>, 48%). Substitution by valine in this position was observed in a lower proportion of isolates (<span class="s1">erg27</span><sup>F412V</sup>, 2%). In contrast to a previous report indicating high fitness cost in isolates carrying <span class="s1">erg27</span><sup>F412S</sup> or <span class="s1">erg27</span><sup>F412I</sup>, mycelium growth and sclerotia development under different restrictive temperatures were not affected compared to wildtype <span class="s1">Erg27</span><sup> F412</sup><span class="Apple-converted-space">&nbsp;</span> in Chilean mutant isolates. At 0°C, <span class="s1">erg27</span><sup>F412S</sup> and <span class="s1">erg27</span><sup>F412I</sup> generated larger lesions than <span class="s1">erg27</span><sup>F412V</sup> and <span class="s1">Erg27</span><sup>F412 </sup>isolates in wounded and unwounded berry assays. Another five mutations were detected in low-resistance <span class="s1">Erg27</span><sup> F412 </sup>isolates; one was<span class="Apple-converted-space">&nbsp; </span>a previously unreported mutation: <span class="s1">erg27</span><sup>R330P</sup>. This study has demonstrated a significant loss of sensitivity to fenhexamid, limited fitness cost and high aggressiveness levels (<span class="s1">erg27</span><sup>F412S </sup>and <span class="s1">erg27</span><sup> F412I</sup>) in field isolates carrying <span class="s1">Erg27</span> mutations, giving dirctions for the design of <span class="s1">Botrytis</span> control programmes based on fenhexamid.</p> 2021-05-13T17:02:35+00:00 Copyright (c) 2021 Marcela ESTERIO, Claudio OSORIO-NAVARRO, Madelaine AZÓCAR, Charleen COPIER, Mauricio RUBILAR, Lorena PIZARRO, Jaime AUGER https://oajournals.fupress.net/index.php/pm/article/view/12183 Neocosmospora spp. associated with dry root rot of citrus in South Africa 2021-05-17T07:50:14+00:00 Vladimiro GUARNACCIA vladimiro.guarnaccia@unito.it Jan VAN NIEKERK janvn@cri.co.za Pedro CROUS p.crous@wi.knaw.nl Marcelo SANDOVAL-DENIS m.sandoval@wi.knaw.nl <p class="p1">Citrus is one of the most important fruit crops cultivated in South Africa. Internationally, citrus dry root rot is a common disease in major citrus production areas. Several abiotic and biotic factors are involved in disease development, in which <span class="s1">Neocosmospora</span> species are important biotic agents. The diversity of <span class="s1">Neocosmospora</span> species associated with dry root rot symptoms of <span class="s1">Citrus </span>trees cultivated in South Africa was evaluated using morphological and molecular analyses. Multi-locus analysis was conducted, based on fragments of seven loci including: ATP citrate lyase (<span class="s1">acl1</span>), calmodulin (<span class="s1">cal</span>), internal transcribed spacer region of the rRNA (ITS), large subunit of the rRNA (LSU), RNA polymerase largest subunit (<span class="s1">rpb1</span>), RNA polymerase second largest subunit (<span class="s1">rpb2</span>), and translation elongation factor 1-alpha (<span class="s1">tef1</span>). A total of 62 strains representing 11 <span class="s1">Neocosmospora </span>species were isolated from crowns, trunks and roots of citrus trees affected by dry root rot, as well as from soils sampled in affected citrus orchards. The most commonly isolated taxa were <span class="s1">N. citricola</span>, <span class="s1">N. ferruginea</span> and <span class="s1">N. solani</span>, while rarely encountered taxa included <span class="s1">N</span>. <span class="s1">brevis</span>, <span class="s1">N</span>. <span class="s1">crassa</span>, <span class="s1">N. hypothenemi</span> and<span class="s1"> N. noneumartii</span>. Furthermore, four <span class="s1">Neocosmospora </span>species are also newly described, namely <span class="s1">N. addoensis</span>, <span class="s1">N. citricola</span>,<span class="s1"> N. gamtoosensis </span>and<span class="s1"> N. lerouxii.</span></p> 2021-05-13T17:17:08+00:00 Copyright (c) 2021 Vladimiro GUARNACCIA, Jan VAN NIEKERK, Pedro CROUS, Marcelo SANDOVAL-DENIS https://oajournals.fupress.net/index.php/pm/article/view/12207 Molecular and serological detection of Parietaria mottle virus in Phytolacca americana, a new host of the virus 2021-05-17T07:50:06+00:00 Giuseppe PARRELLA giuseppe.parrella@ipsp.cnr.it Elisa TROIANO elisa.troiano@ipsp.cnr.it Adriano STINCA adriano.stinca@unina.it Maria Isabella POZZI mariaisabella.pozzi95@gmail.com <p class="p1">Parietaria mottle virus (PMoV) is an emerging virus in Mediterranean countries, responsible for severe disease in tomato and pepper crops in the field and protected cultivation. The principal wild reservoir of PMoV is <span class="s1">Parietaria officinalis</span>, and only few additional wild plants have been described as natural reservoirs of the virus. During field survey in southern Italy, several plants of <span class="s1">Phytolacca americana</span> showing virus-like symptoms were collected. Serological and molecular assays showed that these plants were infected by PMoV. Sequence comparison of the movement protein gene of the PMoV isolate from <span class="s1">P. americana</span> showed the greatest similarity to the corresponding sequence from tomato plants growing nearby. These results indicate that <span class="s1">P. ameriacana</span> is a new natural host of PMoV, and further investigation is warranted to establish the potential of this host as reservoir of the virus in the field.</p> 2021-05-13T17:23:24+00:00 Copyright (c) 2021 Giuseppe PARRELLA, Elisa TROIANO, Adriano STINCA, Maria Isabella POZZI https://oajournals.fupress.net/index.php/pm/article/view/11821 First report of blast of durum wheat in Bangladesh, caused by Magnaporthe oryzae pathotype Triticum 2021-05-17T07:49:56+00:00 Krishna Kanta ROY rkrishnaroy666@gmail.com Muzahid RAHMAN mmer_bari@yahoo.com Kishowar MUSTARIN rimubari@yahoo.com Mostafa Ali REZA marezawrc@gmail.com Paritosh Kumar MALAKER pkmalakerwrc@gmail.com Naresh Chandra DEB BARMA ncdbarma@gmail.com Xinayo HE x.he@cgiar.org Pawan Kumar SINGH PK.singh@cgiar.org <p class="p1">Durum wheat (<span class="s1">Triticum turgidum</span> var. <span class="s1">durum</span> Desf.) is an important cereal crop in many regions of the world. In March of 2018 and 2019, symptoms typical of blast were frequently observed on durum wheat plants under field conditions in Jashore, Bangladesh. The putative causal pathogen was isolated from infected wheat spike specimens onto potato dextrose agar and oatmeal agar, and was identified from mono-conidium cultures as <span class="s1">Magnaporthe oryzae</span>, based on morphological features. The pathotype of the fungus was identified as <span class="s1">Triticum</span>, based on comparative molecular analyses of ITS sequences and MoT3 specific markers. BLAST analysis revealed &gt;99.8% similarity with <span class="s1">M. oryzae/P. oryzae,</span> retrieved from the NCBI Genebank. This was confirmed through amplification of the predicted products with MoT3 primers in PCR analysis. Pathogenicity was confirmed by inoculating healthy durum wheat seedling leaves and spikes with a conidium suspensions of <span class="s1">M</span>. <span class="s1">oryzae</span> isolate DuBWMRI1901.2A. The fungus produced similar symptoms on inoculated leaves and spikes as those observed in the field, and was subsequently re-isolated, fulfilling Koch’s postulates. This is the first report of blast of durum wheat caused by <span class="s1">Magnaporthe oryzae</span> pathotype <span class="s1">Triticum</span> in Bangladesh.</p> 2021-05-13T17:29:42+00:00 Copyright (c) 2021 Krishna Kanta ROY, Muzahid RAHMAN, Kishowar MUSTARIN, Mostafa Ali REZA, Paritosh Kumar MALAKER, Naresh Chandra DEB BARMA, Xinayo HE, Pawan Kumar SINGH https://oajournals.fupress.net/index.php/pm/article/view/11216 Temperature and incubation period affect Septoria pistaciarum conidium germination: disease forecasting and validation 2021-05-17T07:49:46+00:00 Thomas THOMIDIS thomidis@cp.teithe.gr Konstantinos MICHOS k_michos@neuropublic.gr Fotis CHATZIPAPADOPOULOS f_chatzipapadopoulos@neuropublic.gr Amalia TAMPAKI a_tampaki@neuropublic.gr <p class="p1">Septoria leaf spot is an important disease of pistachio trees in Greece. This study aimed to determine effects of temperature and the incubation period on germination of conidia of <span class="s1">Septoria pistaciarum</span>, and to evaluate a generic model to forecast pistachio leaf spot under the field conditions of Aegina Island, Greece. The optimum temperature for conidium germination was 23°C, and germination was inhibited at 35 and 4°C. At constant temperature of 23°C, conidia commenced germination after 9 h. The predictive model indexed disease risk close to 100 at 10 May at two locations (Rachi Moschona and Vigla) in 2017, and first leaf spot symptoms were observed on 17 May. Moderate to high disease severity (&gt;25% leaves infected) were observed in unsprayed trees at the end of May. In 2018, the model indexed risk close to 100 on 9 May at Rachi Moschona, and first symptoms were observed on 18 May. Moderate to high disease severity (&gt;25% leaves infected) were observed in unsprayed trees on 25th of May. This study has shown that the forecasting model can be used in Aegina Island, Greece, to predict the severity of Septoria leaf spot of pistachio.</p> 2021-05-13T17:34:55+00:00 Copyright (c) 2021 Thomas THOMIDIS, Konstantinos MICHOS, Fotis CHATZIPAPADOPOULOS, Amalia TAMPAKI https://oajournals.fupress.net/index.php/pm/article/view/12396 Virulence and diversity of Puccinia striiformis in South Russia 2021-05-17T07:49:39+00:00 Galina V. VOLKOVA galvol@bpp.yandex.ru Olga A. KUDINOVA alosa@list.ru Irina P. MATVEEVA irina.matveeva14@yandex.ru <p class="p1"><span class="s1">Puccinia striiformis </span>causes wheat yield losses in all countries where wheat is cultivated. Virulence and diversity of the <span class="s1">P. striiformis</span> were assessed in 2013–2018 in South Russia, and this showed that the North Caucasian population of the pathogen was diverse. One hundred and eighty two virulence phenotypes were identified in 186 <span class="s1">P. striiformis</span> isolates. Among isolates collected in 2014, 2015, and 2018, all phenotypes were unique. In the 2013 and 2017 populations, phenotypes with few (one to eight) virulence alleles prevailed. In the 2014, 2015, and 2018 populations, most of the phenotypes contained greater numbers (nine to 19) of virulence alleles. Over the 5 years of research, the pathogen population lacked isolates virulent to the host <span class="s1">Yr</span> resistance genes <span class="s1">3, 5, 26, </span>and <span class="s1">Sp</span>. Single (from 1 to 5%) occurrences of isolates virulent to host lines with <span class="s1">Yr</span> genes <span class="s1">3a, 17, 24, 3b + 4a + H46, </span>and <span class="s1">3c + Min</span> were identified. Differences in frequencies of virulence alleles between years in the <span class="s1">P. striiformis</span> populations (Ney indices, N) were generally non-significant (N = 0.11 to 0.23), with the exception of the populations in 2013 and 2017 (N = 0.37). The minimum N values was found for the populations of 2015 and 2018 (N = 0.10). Over the five years of this study, the dynamics of the virulence of the population and jumps in the frequency of isolates with respect to many <span class="s1">Yr</span> genes were identified. This feature of the <span class="s1">P. striiformis</span> populations in South Russia, combined with high phenotypic diversity, indicates the ability for rapid race formation and morphogenesis in response to changes in biotic and abiotic factors.</p> 2021-05-14T07:12:01+00:00 Copyright (c) 2021 Galina V. VOLKOVA, Olga A. KUDINOVA, Irina P. MATVEEVA https://oajournals.fupress.net/index.php/pm/article/view/12170 Bioactive secondary metabolites produced by the emerging pathogen Diplodia olivarum 2021-05-17T07:49:32+00:00 Roberta DI LECCE roberta.dilecce@unina.it Marco MASI marco.masi@unina.it Benedetto Teodoro LINALDEDDU benedetto.linaldeddu@unipd.it Gennaro PESCITELLI gennaro.pescitelli@unipi.it Lucia MADDAU lmaddau@uniss.it Antonio EVIDENTE evidente@unina.it <p class="p1">A new cleistanthane <span class="s1">nor</span>-diterpenoid, named olicleistanone (<span class="s1">1</span>), was isolated as a racemate from the culture filtrates of <span class="s1">Diplodia olivarum</span>, an emerging pathogen involved in the aetiology of branch canker and dieback of several plant species typical of the Mediterranean maquis in Sardinia, Italy. When the fungus was grown <span class="s1">in vitro</span> on Czapek medium, olicleistanone was isolated together with some already known phytotoxic diterpenoids identified as sphaeropsidins A, C, and G, and diplopimarane (<span class="s1">2</span>-<span class="s1">5</span>). Olicleistanone was characterized as 4-ethoxy-6a-methoxy-3,8,8-trimethyl-4,5,8,9,10,11-hexahydrodibenzo[<span class="s1">de,g</span>]chromen-7(6a<span class="s1">H</span>)-one. When <span class="s1">D. olivarum </span>was grown on mineral salt medium it produced (-)-mellein (<span class="s1">6</span>), sphaeropsidin A and small amounts of sphaeropsidin G and diplopimarane. Olicleistanone (<span class="s1">1</span>) exhibited strong activity against the insect <span class="s1">Artemia salina</span> L. (100% larval mortality) at 100 μg mL<sup>-1</sup> but did not exhibit phytotoxic, antifungal or antioomycete activity. Among the metabolites isolated (<span class="s1">1</span>-<span class="s1">6</span>), sphaeropsidin A (<span class="s1">2</span>) was active in all bioassays performed exhibiting strong phytotoxicity on leaves of <span class="s1">Phaseolus vulgaris</span> L., <span class="s1">Juglans regia</span> L. and <span class="s1">Quercus suber</span> L. at 1 mg mL<sup>-1</sup>. Sphaeropsidin A (<span class="s1">2</span>) also completely inhibited mycelium growth of <span class="s1">Athelia rolfsii,</span> <span class="s1">Diplodia corticola</span>, <span class="s1">Phytophthora cambivora</span> and <span class="s1">P. lacustris</span> at 200 μg per plug, and was active in the <span class="s1">Artemia salina</span> assay. Also in this assay, diplopimarane (<span class="s1">5</span>) and sphaeropsidin G (<span class="s1">4</span>) were active (100% larval mortality). Diplopimarane also showed antifungal and antioomycete activities. <span class="s1">Athelia rolfsii</span> was the most sensitive species to diplopimarane. Sphaeropsidin C (<span class="s1">3</span>) and (-)-mellein (<span class="s1">6</span>) were inactive in all bioassays. These results expand knowledge on the metabolic profile of <span class="s1">Botryosphaeriaceae</span>, and embody the first characterization of the main secondary metabolites secreted by <span class="s1">D. olivarum.</span></p> 2021-05-14T07:23:37+00:00 Copyright (c) 2021 Roberta DI LECCE, Marco MASI, Benedetto Teodoro LINALDEDDU, Gennaro PESCITELLI, Lucia MADDAU, Antonio EVIDENTE https://oajournals.fupress.net/index.php/pm/article/view/12019 Antifungal activity of hydroxytyrosol enriched extracts from olive mill waste against Verticillium dahliae, the cause of Verticillium wilt of olive 2021-05-17T07:49:22+00:00 Mounira Inas DRAIS drais@unitus.it Elisa PANNUCCI e.pannucci@unitus.it Rocco CARACCIOLO caracciolo.rocco@gmail.com Roberta BERNINI roberta.bernini@unitus.it Annalisa ROMANI annalisa.romani@unifi.it Luca SANTI luca.santi@unitus.it Leonardo VARVARO varvaro@unitus.it <p class="p1">Verticillium wilt (caused by <span class="s1">Verticillium dahliae</span>&nbsp;Kleb.) is an important disease affecting olive (<span class="s1">Olea europaea</span>&nbsp;L.) production. Effective control of this disease relies on integrated management strategies. <span class="s1">In vitro</span> antifungal activity of two hydroxytyrosol (HTyr) enriched extracts (HTE1 and HTE2) obtained from olive mill waste products (OMWP) was assessed against <span class="s1">V. dahliae.</span> Inhibitory effects of pure HTyr as a standard, and HTE1 and HTE2 at different concentrations, were evaluated on mycelium growth and conidium germination of<span class="s1"> V. dahliae</span>. Chemical characterization of HTE1 and HTE2 allowed identification and quantification of HTyr as the main constituent in both extracts along with other low molecular weight phenols. HTE1 showed a higher inhibitory activity in both growth and conidium germination of <span class="s1">V. dahliae</span>. At the tested concentrations, low antifungal effects of HTyr were observed. After 3 d, 1 mg mL<sup>-1 </sup>of HTE1 gave greater inhibition of mycelium growth than HTE2 or HTyr. After 24 h, HTE1 gave 55% inhibition of conidium germination, and HTyr and HTE2 both gave 37% inhibition. This study has demonstrated that phenolic compounds derived from OMWP have antifungal activity against <span class="s1">V. dahliae</span>, indicating the potential of these compounds for eco-friendly control of Verticillium wilt.</p> 2021-05-14T07:33:13+00:00 Copyright (c) 2021 Mounira Inas DRAIS, Elisa PANNUCCI, Rocco CARACCIOLO, Roberta BERNINI, Annalisa ROMANI, Luca SANTI, Leonardo VARVARO https://oajournals.fupress.net/index.php/pm/article/view/11978 Biocontrol agents and resistance inducers reduce Phytophthora crown rot (Phytophthora capsici) of sweet pepper in closed soilless culture 2021-05-17T16:56:52+00:00 Giovanna GILARDI giovanna.gilardi@unito.it Athina VASILEIADOU athina.vasileiadou@unito.it Angelo GARIBALDI angelo.garibaldi@unito.it Maria Lodovica GULLINO marialodovica.gullino@unito.it <p class="p1"><span class="s1">Twelve trials, in closed soilless culture under controlled conditions, were carried out to evaluate the efficacy of resistance inducers (based on K-phosphite and K-silicate used alone or in combination), and of experimental biocontrol agents (</span><span class="s2">Trichoderma </span><span class="s1">sp.</span> <span class="s1">TW2, a mixture of </span><span class="s2">Pseudomonas</span><span class="s1"> FC 7B, FC 8B, and FC 9B, </span><span class="s2">Fusarium solani </span><span class="s1">FUS25, </span><span class="s2">Pseudomonas </span><span class="s1">sp. PB26), and a commercial formulation of </span><span class="s2">Trichoderma gamsii </span><span class="s1">+ </span><span class="s2">T. asperellum</span><span class="s1">,</span> <span class="s1">against diseases caused by </span><span class="s2">Phytophthora capsici</span><span class="s1"> of sweet pepper. The products were applied using three different protocols, and effects on incidence of Phytophthora crown, stem and root rots (% dead plants), disease development (area under the disease progress curve; AUDPC), and plant fresh weights were evaluated. Potassium phosphite, applied directly at standard P<sub>2</sub>O<sub>5</sub>:K<sub>2</sub>O, 1.30 + 1.05 g L<sup>-1</sup>) and at half standard rates, onto growing media, or via nutrient solution, and before infestation of peat plant growing medium with </span><span class="s2">P. capsici</span><span class="s1">, provided the best disease management in a dose-dependent manner, with an 80% reduction of Phytophthora crown, stem and root rots for the standard dosage and for both types of application. These treatments also reduced proportions of dead plants by 47% from the standard rate and by 62% at the half standard rate, when applied via the nutrient solution or directly to the substrate. K-silicate alone partially reduced the percentage of dead plants, with efficacy of 20–23%. No improvement in disease control was observed when K-silicate was applied in combination with phosphite, while K-silicate alone or combined with K-phosphite reduced disease development, compared to untreated controls. Biocontrol agents (BCAs), applied preventively, reduced Phytophthora crown, stem and root rots,</span> <span class="s1">with similar or better results than those from the commercial mixture of </span><span class="s2">Trichoderma asperellum</span><span class="s1"> + </span><span class="s2">T. gamsii. </span><span class="s1">Among the tested BCAs, </span><span class="s2">Fusarium solani </span><span class="s1">FUS25 provided the most consistent disease reduction (60–65%) and gave increased plant fresh weights. All the tested BCAs reduced disease development, with a similar trend for different disease pressures. The least AUDPC values, compared to the non-treated controls, were from </span><span class="s2">Fusarium solani</span><span class="s1"> FUS25, followed by the tested </span><span class="s2">Pseudomonas </span><span class="s1">strains and </span><span class="s2">Trichoderma</span><span class="s1"> sp. TW2. These results indicate the potential for potassium phosphite and biocontrol agents in management of Phytophthora crown, stem and root rots of pepper grown in soilless systems.</span></p> 2021-05-14T07:43:59+00:00 Copyright (c) 2021 Giovanna GILARDI, Athina VASILEIADOU, Angelo GARIBALDI, Maria Lodovica GULLINO https://oajournals.fupress.net/index.php/pm/article/view/11985 Detection and phylogeny of viruses in native Albanian olive varieties 2021-05-17T07:49:03+00:00 Toufic ELBEAINO elbeaino@iamb.it Magdalena CARA mcara@ubt.edu.al Shpend SHAHINI shpend.shahini@gmail.com Pasko PANDELI pasko@iamb.it <p class="p1">Forty samples representing 14 native Albanian and two foreign olive varieties were collected from an olive varietal collection plot in the Valias region (Tirana, Albania). The samples were assayed by RT-PCR for presence of olive-infecting viruses, including arabis mosaic virus (ArMV), cherry leaf roll virus (CLRV), cucumber mosaic virus (CMV), olive latent ringspot virus (OLRSV), olive latent virus 1 (OLV-1), olive leaf yellowing-associated virus (OLYaV), strawberry latent ringspot virus (SLRSV) and by PCR for the bacterium<span class="s1"> Xylella fastidiosa</span> (Xf). Ninety-eight percent of the samples were infected with at least one virus. OLYaV was the most prevalent (85% of samples), followed by OLV-1 (50%), OLRSV (48%), CMV (28%), SLRSV (3%) and CLRV (5%), whereas ArMV and Xf were absent. Fifty-five percent of the samples were infected with one virus, 13% with two viruses, 20% with three, and 5% with four. Analyses of the nucleotide sequences of the Albanian virus isolates generally showed low genetic variability, and that most were phylogenetically related to Mediterranean isolates, in particular to those from Greece and Italy. Five olive trees, representing three native cultivars (‘Managiel’, ‘Kalinjot’ and ‘Kushan-Preze’) and one foreign (‘Leccino’), were found to be plants of the <span class="s1">Conformitas Agraria Communitatis</span> (“<span class="s1">CAC</span>”) category i.e<span class="s1">.</span> free of ArMV, CLRV, SLRSV and OLYaV. Only one tree of the native cultivar ‘Ulliri i kuq’ was free of all tested viruses, so this is plant material of the “Virus-tested” category. Olives derived from both categories could be used for propagation of standard quality plant materiel in a future certification programme for olive in Albania. This is the first report of CLRV, OLRSV, CMV and OLV-1 in Albania. The study also reveals the precarious health status of native olive varieties in the Valias varietal collection plot. However, the discovery of six plants representing two certifiable categories is a first step in a future olive tree certification program in the country.</p> 2021-05-14T07:50:57+00:00 Copyright (c) 2021 Toufic ELBEAINO, Magdalena CARA, Shpend SHAHINI, Pasko PANDELI