The complex of Diplodia species associated with Fraxinus and some other woody hosts in Italy and Portugal

Isolation, molecular characterization and first report of Dothiorella gregaria associated with fruit rot of walnuts of Jammu and Kashmir, India

Walnuts are known for their high levels of antioxidants, which are linked to various health benefits. However, challenges related to distribution and storage, as well as the risk of fungal infections, can affect the quality of walnut kernels. Fungal pathogens from the Botryosphaeriaceae family, including Dothiorella species and Diplodia species, can damage fruit and reduce its antioxidant content. To comprehend the cause of fruit rot in walnuts, Dothiorella gregaria isolates were studied using polyphasic methods, including multiple gene sequences and morphological identification, as well as analysis of polyphenol content and pathogenicity. The walnuts kernels purchased from market places of Jammu and Kashmir (J&K), India were observed to be affected by Dothiorella gregaria species causing the quality detoriation and decrease in polyphenol content thus undeniably with decreased antioxidant properties. D. gregaria Infected walnut kernels were having some brown and black spots and some were having white mycelial growth and however, most samples were asymptomatic. Pathogenicity testing revealed that the pathogen was able to develop all the symptoms under experimental conditions and the reisolated pathogen was morphologically similar to D. gregaria. The samples infected with this pathogen showed considerable decrease in polyphenol content, 10.9 ± 2.66 mgGAE/g (mean ± standard deviation) thus decreased antioxidant quality as compared to the samples which showed zero incidence of this pathogen, 52.50 ± 4.27 mgGAE/g (mean ± standard deviation). Furthermore, the pathogen was studied using polyphasic approach involving morphological, molecular and phylogenetic analysis. Combined nucleotide dataset of nuclear ribosomal ITS and tef1-α revealed that Dothiorella gregaria (NY6) formed a clade with Dothiorlla iberica (MAEC33), Dothiorella sarmentorium (MAEC28) and Dothiorella iberica (CAA905) strains with 83% bootstrap support. Besides, we observed six nucleotide changes, four were insertions or deletions and two were substitutions in the 502-bp region of the ITS rRNA gene when we compared our isolate to the most equivalent sequences submitted to NCBI GenBank. This is the first report of Dothiorella gregaria affecting walnuts purchased from various markets in J&K, India, causing fruit rot in walnuts after harvest. Given that local farmers store and export walnuts, it could pose an emerging threat to their livelihood. Thus, creating post-harvesting interventions for D. gregaria and knowing more about the fruit rot in walnuts can be benefited from morphological and molecular identification using several gene loci, genetic variability in the ITS rRNA gene, and total phenol analysis.

Re-Evaluating Botryosphaeriales: Ancestral State Reconstructions of Selected Characters and Evolution of Nutritional Modes

Botryosphaeriales (Dothideomycetes, Ascomycota) occur in a wide range of habitats as endophytes, saprobes, and pathogens. The order Botryosphaeriales has not been subjected to evaluation since 2019 by Phillips and co-authors using phylogenetic and evolutionary analyses. Subsequently, many studies introduced novel taxa into the order and revised several families separately. In addition, no ancestral character studies have been conducted for this order. Therefore, in this study, we re-evaluated the character evolution and taxonomic placements of Botryosphaeriales species based on ancestral character evolution, divergence time estimation, and phylogenetic relationships, including all the novel taxa that have been introduced so far. Maximum likelihood, maximum parsimony, and Bayesian inference analyses were conducted on a combined LSU and ITS sequence alignment. Ancestral state reconstruction was carried out for conidial colour, septation, and nutritional mode. Divergence times estimates revealed that Botryosphaeriales originated around 109 Mya in the early epoch of the Cretaceous period. All six families in Botryosphaeriales evolved in the late epoch of the Cretaceous period (66-100 Mya), during which Angiosperms also appeared, rapidly diversified and became dominant on land. Families of Botryosphaeriales diversified during the Paleogene and Neogene periods in the Cenozoic era. The order comprises the families Aplosporellaceae, Botryosphaeriaceae, Melanopsaceae, Phyllostictaceae, Planistromellaceae and Saccharataceae. Furthermore, current study assessed two hypotheses; the first one being "All Botryosphaeriales species originated as endophytes and then switched into saprobes when their hosts died or into pathogens when their hosts were under stress"; the second hypothesis states that "There is a link between the conidial colour and nutritional mode in botryosphaerialean taxa". Ancestral state reconstruction and nutritional mode analyses revealed a pathogenic/saprobic nutritional mode as the ancestral character. However, we could not provide strong evidence for the first hypothesis mainly due to the significantly low number of studies reporting the endophytic botryosphaerialean taxa. Results also showed that hyaline and aseptate conidia were ancestral characters in Botryosphaeriales and supported the relationship between conidial pigmentation and the pathogenicity of Botryosphaeriales species.

Diplofuranoxin, a disubstituted dihydrofuranone, was produced together with sphaeropsidin A and epi-sphaeropsidone by Diplodia subglobosa, an emerging ash (Fraxinus excelsior L.) pathogen in Europe

An undescribed disubstituted dihydrofuranone, named diplofuranoxin, was isolated, together with the six well known metabolites sphaeropsidins A and C, epi-sphaeropsidone, mellein and cis- and trans-4-hydroxymelleins, from the fungal species Diplodia subglobosa, an emerging pathogen involved in the ash dieback aetiology in Europe. Currently, the disease represents the main threat to European ash heritage and the wood associated industry. Diplofuranoxin, was characterized essentially by NMR and HRESIMS spectra as (3Z)-3-(2,3-dihydroxybutylidene)-5-methyldihydrofuran-2(3H)-one. Its relative and absolute configuration was determined by joining NOESY NMR experiments and computational analysis of electronic circular dichroism spectrum. All the metabolites were screened for phytotoxic, antioomycetes and zootoxic activities and only sphaeropsidin A and epi-sphaeropsidone were active in two out of three bioassays performed. In addition, sphaeropsidin A completely inhibited mycelium growth of Phytophthora cambivora, whereas the inhibition rate of epi-sphaeropsidone was less than 50% at the higher concentration used. Both metabolites were inactive in the Artemia salina assay. Results obtained in this study have allowed to characterize for the first time the main metabolites produced in vitro by D. subglobosa and to increase the knowledge on the metabolic profile of Botryosphaeriaceae for a correct taxonomic classification of the strains belonging to this family.

Current Insight into Traditional and Modern Methods in Fungal Diversity Estimates

Fungi are an important and diverse component in various ecosystems. The methods to identify different fungi are an important step in any mycological study. Classical methods of fungal identification, which rely mainly on morphological characteristics and modern use of DNA based molecular techniques, have proven to be very helpful to explore their taxonomic identity. In the present compilation, we provide detailed information on estimates of fungi provided by different mycologistsover time. Along with this, a comprehensive analysis of the importance of classical and molecular methods is also presented. In orderto understand the utility of genus and species specific markers in fungal identification, a polyphasic approach to investigate various fungi is also presented in this paper. An account of the study of various fungi based on culture-based and cultureindependent methods is also provided here to understand the development and significance of both approaches. The available information on classical and modern methods compiled in this study revealed that the DNA based molecular studies are still scant, and more studies are required to achieve the accurate estimation of fungi present on earth.

Fungi of quarantine concern for China I: Dothideomycetes

The current list of Chinese quarantine pests includes 130 fungal species. However, recent changes in the taxonomy of fungi following the one fungus = one name initiative and the implementation of DNA phylogeny in taxonomic revisions, resulted in many changes of these species names, necessitating an update of the current list. In addition, many quarantine fungi lack modern morphological descriptions and authentic DNA sequences, posing significant challenges for the development of diagnostic protocols. The aim of the present study was to review the taxonomy and names of the 33 Chinese quarantine fungi in Dothideomycetes, and provide reliable DNA barcodes to facilitate rapid identification. Of these, 23 names were updated according to the single name nomenclature system, including one new combination, namely Cophinforma tumefaciens comb. nov. (syn. Sphaeropsis tumefaciens). On the basis of phylogenetic analyses and morphological comparisons, a new genus Xenosphaeropsis is introduced to accommodate the monotypic species Xenosphaeropsis pyriputrescens comb. nov. (syn. Sphaeropsis pyriputrescens), the causal agent of a post-harvest disease of pears. Furthermore, four lectotypes (Ascochyta petroselini, Mycosphaerella ligulicola, Physalospora laricina, Sphaeria lingam), three epitypes (Ascochyta petroselini, Phoma lycopersici, Sphaeria lingam), and two neotypes (Ascochyta pinodella, Deuterophoma tracheiphila) are designated to stabilise the use of these names. A further four reference strains are introduced for Cophinforma tumefaciens, Helminthosporium solani, Mycocentrospora acerina, and Septoria linicola. In addition, to assist future studies on these important pathogens, we sequenced and assembled whole genomes for 17 species, including Alternaria triticina, Boeremia foveata, B. lycopersici, Cladosporium cucumerinum, Didymella glomerata, Didymella pinodella, Diplodia mutila, Helminthosporium solani, Mycocentrospora acerina, Neofusicoccum laricinum, Parastagonospora pseudonodorum, Plenodomus libanotidis, Plenodomus lingam, Plenodomus tracheiphilus, Septoria petroselini, Stagonosporopsis chrysanthemi, and Xenosphaeropsis pyriputrescens. Citation: Zhao P, Crous PW, Hou LW, et al. 2021. Fungi of quarantine concern for China I: Dothideomycetes. Persoonia 47: 45-105. https://doi.org/10.3767/persoonia.2021.47.02.

https://botryosphaeriales.org/, an online platform for up-to-date classification and account of taxa of Botryosphaeriales

Fungi are eukaryotes that inhabit various ecosystems worldwide and have a decomposing effect that other organisms cannot replace. Fungi are divided into two main groups depending on how their sexual spores are formed, viz. Ascomycota and Basidiomycota. The members of Botryosphaeriales (Dothideomycetes, Ascomycota) are ubiquitous. They are pathogenic on a wide range of hosts, causing diverse diseases including dieback, canker, leaf spots and root rots and are also reported as saprobes and endophytes worldwide. As an important fungal group, of which most are plant pathogens, it is necessary to organize data and information on Botryosphaeriales so that scientific literature can be used effectively. For this purpose, a new website, https://botryosphaeriales.org is established to gather all published data together with updates on the present taxonomy of Botryosphaeriales. The website consists of an easy-to-operate searching system and provides an up-to-date classification together with accounts of Botryosphaeriales taxa, including colour illustrations, descriptions, notes and numbers of species in each genus, as well as their classification. Thus, readers will be able to obtain information on botryosphaerialean taxa through this platform. Database URL: https://botryosphaeriales.org/.

Genetic Diversity and Pathogenicity of Botryosphaeriaceae Species Associated with Symptomatic Citrus Plants in Europe

This study represents the first survey studying the occurrence, genetic diversity, and pathogenicity of Botryosphaeriaceae species associated with symptomatic citrus species in citrus-production areas in five European countries. Based on morphological features and phylogenetic analyses of internal transcribed spacer (ITS) of nuclear ribosomal DNA (nrDNA), translation elongation factor 1-alpha (TEF1) and β-tubulin (TUB2) genes, nine species were identified as belonging to the genera Diplodia, Dothiorella, Lasiodiplodia, and Neofusicoccum. Isolates of Neofusicoccum parvum and Diplodia pseudoseriata were the most frequently detected, while Dothiorella viticola had the widest distribution, occurring in four of the five countries sampled. Representative isolates of the nine Botryosphaeriaceae species used in the pathogenicity tests caused similar symptoms to those observed in nature. Isolates assayed were all re-isolated, thereby fulfilling Koch's postulates. Isolates of Diplodia pseudoseriata and Diplodia olivarum are recorded for the first time on citrus and all species found in our study, except N. parvum, are reported for the first time on citrus in Europe.

Early Season Symptoms on Stem, Inflorescences and Flowers of Grapevine Associated with Botryosphaeriaceae Species

Botryosphaeria dieback caused by several Botryosphaeriaceae species is one of the most important grapevine trunk diseases affecting vineyards worldwide. These fungi cause wedge-shaped perennial cankers and black streaking of the wood and have also been associated with intervein leaf chlorosis, dried or mummified berries, and eventually, the death of the plant. Early season symptoms may sometimes be disregarded by growers, being mistaken with symptoms from other diseases such as downy mildew or botrytis rot. Currently, few studies are available to determine what species may be causing these early season symptoms in grapevines. During the 2018 season, during the flowering period, grapevine samples showing necrosis on green shoots, dried inflorescences, and flowers, were collected in vineyards throughout the central regions of Portugal. Isolations were performed from symptomatic organs, and twenty-three isolates of Botryosphaeriaceae were selected. An analysis of the ITS and part of the translation elongation factor 1-α sequences was performed, revealing that the two main species apparently responsible for these symptoms were Diplodia seriata and Neofusicoccum parvum. In pathogenicity tests conducted on 1-year-old plants grown under controlled conditions in a greenhouse and on field-grown clusters, symptoms were reproduced, confirming the pathogenic behavior of the selection of isolates.

Diplodia fraxini and Diplodia subglobosa: The Main Species Associated with Cankers and Dieback of Fraxinus excelsior in North-Eastern Italy

In Italy, after the first report in Friuli-Venezia Giulia along the border with Slovenia in 2009, ash dieback has successively been reported in Veneto, Tuscany and Trentino-Alto Adige. Given its alarming expansion in European ash formations along the sub-montane belt of north-eastern Italy and the limited information about the associated fungal microorganisms; since 2017, a study has been conducted in order to isolate and characterize the fungal species involved in the aetiology of the disease. The surveys were conducted in six ash–maple forests distributed along the Veneto and Friuli-Venezia Giulia pre-Alpine regions (Italy). In each site, the health status of ash trees was assessed and a sample (shoot or branch) with the typical symptoms of the disease was taken from ten trees to isolate the associated pathogens. The fungal colonies developed were identified using morphological features and DNA sequences. The 60 samples processed yielded a total of 109 fungal isolates belonging to 9 families including: Botryosphaeriaceae (62 isolates), Diaporthaceae (18), Nectriaceae (10), Didymellaceae (9), Helotiaceae (5), Diatrypaceae (2), Didymosphaeriaceae (1), Phaeosphaeriaceae (1) and Valsaceae (1). In particular, three species—Diplodia subglobosa, Diplodia fraxini and Diaporthe eres—were isolated with high frequency, while Hymenoscyphus fraxineus was isolated from only five plants distributed in four sites. The pathogenicity tests, conducted on 3-year-old seedlings, detached branches (3–4 cm diameter), and leaves of Fraxinus excelsior, showed that Diplodia fraxini is the most virulent species and the only one able to reproduce the symptoms observed in nature. Overall, the results obtained emphasize that several fungal pathogens are involved in the aetiology of the disease, many of which belong to the Botryosphaeriaceae family.

Fungal diversity notes 1151–1276: taxonomic and phylogenetic contributions on genera and species of fungal taxa

Fungal diversity notes is one of the important journal series of fungal taxonomy that provide detailed descriptions and illustrations of new fungal taxa, as well as providing new information of fungal taxa worldwide. This article is the 11th contribution to the fungal diversity notes series, in which 126 taxa distributed in two phyla, six classes, 24 orders and 55 families are described and illustrated. Taxa in this study were mainly collected from Italy by Erio Camporesi and also collected from China, India and Thailand, as well as in some other European, North American and South American countries. Taxa described in the present study include two new families, 12 new genera, 82 new species, five new combinations and 25 new records on new hosts and new geographical distributions as well as sexual-asexual reports. The two new families are Eriomycetaceae (Dothideomycetes, family incertae sedis) and Fasciatisporaceae (Xylariales, Sordariomycetes). The twelve new genera comprise Bhagirathimyces (Phaeosphaeriaceae), Camporesiomyces (Tubeufiaceae), Eriocamporesia (Cryphonectriaceae), Eriomyces (Eriomycetaceae), Neomonodictys (Pleurotheciaceae), Paraloratospora (Phaeosphaeriaceae), Paramonodictys (Parabambusicolaceae), Pseudoconlarium (Diaporthomycetidae, genus incertae sedis), Pseudomurilentithecium (Lentitheciaceae), Setoapiospora (Muyocopronaceae), Srinivasanomyces (Vibrisseaceae) and Xenoanthostomella (Xylariales, genera incertae sedis). The 82 new species comprise Acremonium chiangraiense, Adustochaete nivea, Angustimassarina camporesii, Bhagirathimyces himalayensis, Brunneoclavispora camporesii, Camarosporidiella camporesii, Camporesiomyces mali, Camposporium appendiculatum, Camposporium multiseptatum, Camposporium septatum, Canalisporium aquaticium, Clonostachys eriocamporesiana, Clonostachys eriocamporesii, Colletotrichum hederiicola, Coniochaeta vineae, Conioscypha verrucosa, Cortinarius ainsworthii, Cortinarius aurae, Cortinarius britannicus, Cortinarius heatherae, Cortinarius scoticus, Cortinarius subsaniosus, Cytospora fusispora, Cytospora rosigena, Diaporthe camporesii, Diaporthe nigra, Diatrypella yunnanensis, Dictyosporium muriformis, Didymella camporesii, Diutina bernali, Diutina sipiczkii, Eriocamporesia aurantia, Eriomyces heveae, Ernakulamia tanakae, Falciformispora uttaraditensis, Fasciatispora cocoes, Foliophoma camporesii, Fuscostagonospora camporesii, Helvella subtinta, Kalmusia erioi, Keissleriella camporesiana, Keissleriella camporesii, Lanspora cylindrospora, Loratospora arezzoensis, Mariannaea atlantica, Melanographium phoenicis, Montagnula camporesii, Neodidymelliopsis camporesii, Neokalmusia kunmingensis, Neoleptosporella camporesiana, Neomonodictys muriformis, Neomyrmecridium guizhouense, Neosetophoma camporesii, Paraloratospora camporesii, Paramonodictys solitarius, Periconia palmicola, Plenodomus triseptatus, Pseudocamarosporium camporesii, Pseudocercospora maetaengensis, Pseudochaetosphaeronema kunmingense, Pseudoconlarium punctiforme, Pseudodactylaria camporesiana, Pseudomurilentithecium camporesii, Pseudotetraploa rajmachiensis, Pseudotruncatella camporesii, Rhexocercosporidium senecionis, Rhytidhysteron camporesii, Rhytidhysteron erioi, Septoriella camporesii, Setoapiospora thailandica, Srinivasanomyces kangrensis, Tetraploa dwibahubeeja, Tetraploa pseudoaristata, Tetraploa thrayabahubeeja, Torula camporesii, Tremateia camporesii, Tremateia lamiacearum, Uzbekistanica pruni, Verruconis mangrovei, Wilcoxina verruculosa, Xenoanthostomella chromolaenae and Xenodidymella camporesii. The five new combinations are Camporesiomyces patagoniensis, Camporesiomyces vaccinia, Camposporium lycopodiellae, Paraloratospora gahniae and Rhexocercosporidium microsporum. The 22 new records on host and geographical distribution comprise Arthrinium marii, Ascochyta medicaginicola, Ascochyta pisi, Astrocystis bambusicola, Camposporium pellucidum, Dendryphiella phitsanulokensis, Diaporthe foeniculina, Didymella macrostoma, Diplodia mutila, Diplodia seriata, Heterosphaeria patella, Hysterobrevium constrictum, Neodidymelliopsis ranunculi, Neovaginatispora fuckelii, Nothophoma quercina, Occultibambusa bambusae, Phaeosphaeria chinensis, Pseudopestalotiopsis theae, Pyxine berteriana, Tetraploa sasicola, Torula gaodangensis and Wojnowiciella dactylidis. In addition, the sexual morphs of Dissoconium eucalypti and Phaeosphaeriopsis pseudoagavacearum are reported from Laurus nobilis and Yucca gloriosa in Italy, respectively. The holomorph of Diaporthe cynaroidis is also reported for the first time.

Mating type gene analyses in the genus Diplodia: From cryptic sex to cryptic species

Cryptic species are common in Diplodia, a genus that includes some well-known and economically important plant pathogens. Thus, species delimitation has been based on the phylogenetic species recognition approach using multigene genealogies. We assessed the potential of mating type (MAT) genes sequences as phylogenetic markers for species delimitation in the genus Diplodia. A PCR-based mating type diagnostic assay was developed that allowed amplification and sequencing of the MAT1-1-1 and MAT1-2-1 genes, and determination of the mating strategies used by different species. All species tested were shown to be heterothallic. Phylogenetic analyses were performed on both MAT genes and also, for comparative purposes, on concatenated sequences of the ribosomal internal transcribed spacer (ITS), translation elongation factor 1-alpha (tef1-α) and beta-tubulin (tub2). Individual phylogenies based on MAT genes clearly differentiated all species analysed and agree with the results obtained with the commonly used multilocus phylogenetic analysis approach. However, MAT genes genealogies were superior to multigene genealogies in resolving closely related cryptic species. The phylogenetic informativeness of each locus was evaluated revealing that MAT genes were the most informative loci followed by tef1-α. Hence, MAT genes can be successfully used to establish species boundaries in the genus Diplodia.

Fraxitoxin, a New Isochromanone Isolated from Diplodia fraxini

A new isochromanone, named fraxitoxin, was isolated together with (-)-mellein and tyrosol from liquid cultures of Diplodia fraxini, a pathogen involved in the etiology of canker and dieback disease of Fraxinus spp. in Europe. It was characterized as 5-methoxy-3-methylisochroman-1-one using spectroscopic methods (essentially NMR and HR-EI-MS). Its absolute configuration (R) at C(3) was assigned by electronic circular dichroism (ECD) measurements and calculations. Phytotoxic activity of the compound was evaluated on ash, cork and holm oak leaves at concentration of 1 mg/ml by the leaf-puncture assay. Interestingly, fraxitoxin caused necrotic lesions only on ash leaves.

Botryosphaeriaceae Species Associated With Cankers and Dieback Symptoms of Acacia mangium and Pinus caribaea var. hondurensis in Venezuela

Several species in the Botryosphaeriaceae family cause wood stain, cankers, and dieback of trunks and branches in a wide range of forest tree species. The aim of this study was to characterize the botryosphaeriaceous fungi associated with decline symptoms observed in Acacia mangium and Pinus caribaea var. hondurensis, two economically important forest tree species grown in commercial plantations in Venezuela. Fungi isolated from symptomatic samples collected from both hosts in commercial sites were identified based on their morphology and DNA sequences of the internal transcribed spacer region (ITS1-5.8S-ITS2) and part of the β-tubulin and translation elongation factor 1-α genes. Lasiodiplodia theobromae and L. venezuelensis were routinely isolated from A. mangium and P. caribaea var. hondurensis. Additionally, the novel species Diplodia guayanensis was isolated and characterized from symptomatic and asymptomatic tissues of A. mangium. Multigene phylogenetic analyses along with restriction fragment length polymorphism studies further supported the identification of these species. A pathogenicity study was conducted under natural conditions and 12 weeks after inoculation all Botryosphaeriaceae spp. were shown to be highly virulent on A. mangium. Contrary, no lesions were observed in the wood of P. caribaea var. hondurensis when inoculated with L. theobromae and L. venezuelensis. However, both species were consistently reisolated from the asymptomatic tissue beyond the inoculation point. This study contributes to a better understand the role that species in the Botryosphaeriaceae play on disease symptoms and dieback of A. mangium and P. caribaea var. hondurensis from plantations in eastern Venezuela.

Families, genera, and species of Botryosphaeriales

Members of Botryosphaeriales are ecologically diverse, but most commonly associated with leaf spots, fruit and root rots, die-back or cankers of diverse woody hosts. Based on morphology and DNA sequence data, the Botryosphaeriales have to date been shown to contain eight families, with an additional two, Endomelanconiopsisaceae (Endomelanconiopsis) and Pseudofusicoccumaceae (Pseudofusicoccum) being newly described in this study. Furthermore, Oblongocollomyces is introduced as new genus, while Spencermartinsia is reduced to synonymy under Dothiorella. Novel species include Diplodia pyri (Pyrus sp., the Netherlands), Diplodia citricarpa (Citrus sp., Iran), Lasiodiplodia vitis (Vitis vinifera, Italy), L. sterculiae (Sterculia oblonga, Germany), Neofusicoccum pistaciarum (Pistacia vera, USA), N. buxi (Buxus sempervirens, France), N. stellenboschiana (Vitis vinifera, South Africa), and Saccharata hawaiiensis (Protea laurifolia, Hawaii). New combinations are also proposed for Camarosporium pistaciae (associated with fruit rot of Pistacia vera) in Neofusicoccum, and Sphaeria gallae (associated with galls of Quercus) in Diplodia. The combination of large subunit of the nuclear ribosomal RNA gene (LSU)-rpb2 proved effective at delineating taxa at family and generic level. Furthermore, rpb2 also added additional resolution for species delimitation, in combination with ITS, tef1 and tub2. In this study we analysed 499 isolates, and produce an expanded phylogenetic backbone for Botryosphaeriales, which will help to delimit novelties at species, genus and family level in future.

Endemic and Emerging Pathogens Threatening Cork Oak Trees: Management Options for Conserving a Unique Forest Ecosystem

Cork oak (Quercus suber) forests are economically and culturally intertwined with the inhabitants of the Mediterranean basin and characterize its rural landscape. These forests cover over two million hectares in the western Mediterranean basin and sustain a rich biodiversity of endemisms as well as representing an important source of income derived from cork production. Currently cork oak forests are threatened by several factors including human-mediated disturbances such as poor or inappropriate management practices, adverse environmental conditions (irregular water regime with prolonged drought periods), and attacks of pathogens and pests. All these adverse factors can interact, causing a complex disease commonly known as "oak decline." Despite the numerous investigations carried out so far, decline continues to be the main pathological problem of cork oak forests because of its complex etiology and the resulting difficulties in defining suitable control strategies. An overview of the literature indicates that several pathogenic fungi and oomycota can play a primary role in the etiology of this syndrome. Therefore, the aim of this review is to analyze the recent advances achieved regarding the bio-ecology of the endemic and emerging pathogens that threaten cork oak trees with particular emphasis on the species more directly involved in oak decline. Moreover, the effect of climate change on the host-pathogen interactions, a task fundamental for making useful decisions and managing cork oak forests properly, is considered.

Diplopimarane, a 20-nor-ent-pimarane produced by the oak pathogen Diplodia quercivora

In this study a new 20-nor-ent-pimarane, named diplopimarane, was isolated together with sphaeropsidins A (9) and C (10), and (+)-epiepoformin (11) from organic crude extracts of Diplodia quercivora, a recently described oak pathogen originally found on declining Quercus canariensis trees in Tunisia. Diplopimarane was characterized as (1S,2R)-2,8,8-trimethyl-2-vinyl-1,2,3,4,5,6,7,8-octahydrophenanthrene-1,9,10-triol by spectroscopic, X-ray, optical, and chemical methods. It exhibited a wide range of activities including remarkable phytotoxicity on nonhost plants such as tomato cuttings, moderate antifungal activity against important plant pathogens, and moderate zootoxicity against Artemia salina. Its derivatives (2-4 and 6) were also tested for their phytotoxic and zootoxic activities. All these derivatives proved to be active against A. salina at 200 μg/mL, while 2 and 6 were also active on tomato cuttings. The other secondary metabolites (9, 10, and 11) herein reported for D. quercivora exhibited phytotoxic, antifungal, and zootoxic activity. This is the first report on the secondary metabolites secreted in vitro by this oak pathogen that could be key components of its adaptative strategies.