Diatrypaceous Fungi Research Articles

 Stromatolinea, a new diatrypaceous fungal genus (Ascomycota, Sordariomycetes, Xylariales, Diatrypaceae) from China.

Molecular phylogeny and morphological characteristics of collections of diatrypaceous fungi from Guizhou Province, China, lead to the establishment of a new genus, Stromatolinea, and the identification of four new species and two new combinations. The taxa were found growing on the dead culms of Phyllostachys bamboo. The new genus is distinguished by its well-developed, discrete linear stromata with yellow interior tissue and allantoid subhyaline ascospores. The newly described species are Stromatolineagrisea, S.guizhouensis, S.hydei, and S.xishuiensis. Additionally, two new combinations, Stromatolinealinearis and S.phaselina, are proposed based on comparative analysis and morphology. Phylogenetic analyses were conducted using ITS and TUB2 sequences. The study includes comprehensive morphological descriptions, illustrations, and a phylogenetic tree depicting the placement of the new taxa.

Molecular detection and identification of Diatrypaceous airborne spores in Australian vineyards revealed high species diversity between regions.

The grapevine trunk disease, Eutypa dieback (ED), causes significant vine decline and yield reduction. For many years, the fungus Eutypa lata was considered the main pathogen causing ED of grapevines in Australia. Recent studies showed other Diatrypaceous fungi were also associated with vines exhibiting dieback symptoms but there is limited information on how these fungal pathogens spread in vineyards. Thus, information on the spore dispersal patterns of Diatrypaceous fungi in different wine regions will assist in identifying high-risk infection periods in vineyards. Using more than 6800 DNA samples from airborne spores collected from eight wine regions in south-eastern Australia over 8 years using a Burkard spore trap, this study investigated the diversity and abundance of Diatrypaceous species, using multi-faceted molecular tools. A multi-target quantitative PCR (qPCR) assay successfully detected and quantified Diatrypaceous spores from 30% of the total samples with spore numbers and frequency of detection varying between regions and years. The high-resolution melting analysis (HRMA) coupled with DNA sequencing identified seven species, with E. lata being present in seven regions and the most prevalent species in the Adelaide Hills, Barossa Valley and McLaren Vale. Cryptovalsa ampelina and Diatrype stigma were the predominant species in the Clare Valley and Coonawarra, respectively while Eutypella citricola and Eu. microtheca dominated in the Hunter Valley and the Riverina regions. This study represents the first report of D. stigma and Cryptosphaeria multicontinentalis in Australian vineyards. This study further showed rainfall as a primary factor that triggers spore release, however, other weather factors that may influence the spore release in different climatic regions of Australia still requires further investigation.

Taxonomic and phylogenetic contributions to Diatrypaceae from southeastern Tibet in China.

In this study, we investigated the diversity of diatrypaceous fungi from southeastern Tibet in China. The phylogenetic analyses were carried out based on ITS and β-tubulin sequences of 75 taxa of Diatrypaceae from around the world. Based on a combination of morphological features and molecular evidence, a new genus-Alloeutypa, with three new species-A. milinensis, Diatrype linzhiensis, and Eutypella motuoensis, and a new combination-A. flavovirens, were revealed by the materials in China. Alloeutypa is characterized by stromatal interior olivaceous buff, stromata producing well-developed discrete, and ascospores allantoid, subhyaline. These characteristics separate the new genus from the similar genus Eutypa. Comprehensive morphological descriptions, illustrations, and a phylogenetic tree to show the placement of new taxa are provided. All novelties described herein are morphologically illustrated and phylogeny investigated to better integrate taxa into the higher taxonomic framework and infer their phylogenetic relationships as well as establish new genera and species. Our results indicate that the diatrypaceous fungi harbor higher species diversity in China.

The Hidden Diversity of Diatrypaceous Fungi in China.

In this study, we investigated the diversity of diatrypaceous fungi from six regions in China based on morpho-molecular analyses of combined ITS and tub2 gene regions. We accept 23 genera in Diatrypaceae with 18 genera involved in the phylogram, and the other five genera are lacking living materials with sequences data. Eleven species included in four genera (viz. Allocryptovalsa, Diatrype, Diatrypella, and Eutypella) have been isolated from seven host species, of which nine novel species (viz. Allocryptovalsa castaneae, A. castaneicola, Diatrype betulae, D. castaneicola, D. quercicola, Diatrypella betulae, Da. betulicola, Da. hubeiensis, and Da. shennongensis), a known species of Diatrypella favacea, and a new record of Eutypella citricola from the host genus Morus are included. Current results show the high diversity of Diatrypaceae which are wood-inhabiting fungi in China.

Modern Taxonomic Approaches to Identifying Diatrypaceous Fungi from Marine Habitats, with a Novel Genus Halocryptovalsa Dayarathne & K.D.Hyde, Gen. Nov.

Marine diatrypaceous fungi are associated with many host species, including Avicennia spp., Halosarceia halocnemoides (Nees) Paul G.Wilson, Kandelia candel (L.) Druce, Salicornia sp., Rhizophora apiculata Blume and Suaeda fruticosa (L.) Forssk. Accurate morphological identification of individual taxa of this family is difficult, as previous classifications generally lack sequence data. We provide a detailed account of all known marine diatrypaceous taxa and determine their phylogenetic and morphological relationships. A novel genus Halocryptovalsa Dayarathne & K.D.Hyde, gen. nov. is established to accommodate Halocryptovalsa salicorniae Dayarathne & K.D.Hyde, sp. nov., and Halocryptovalsa avicenniae, comb. nov. (synonym of Cryptovalsa avicenniae). Three novel species Cryptosphaeria avicenniae Devadatha & V.V.Sarma, sp. nov., Cryptosphaeria halophila Dayarathne & K.D.Hyde, sp. nov., and Diatrype mangrovei Dayarathne & K.D.Hyde, sp. nov., are introduced from mangroves. Halodiatrype is amended with asexual morph characters.

A new genus Allodiatrype, five new species and a new host record of diatrypaceous fungi from palms (Arecaceae)

A new genus Allodiatrype, five new species and a new host record of diatrypaceous fungi from palms (Arecaceae)

Taxonomy and molecular phylogeny of Diatrypaceae (Ascomycota, Xylariales) species from the Brazilian semi-arid region, including four new species

Members of the Diatrypaceae are predominantly saprotrophic on the decaying wood of angiosperms worldwide and the family has received little attention due to its difficult taxonomy. However, the recent detection of several pathogenic species, once considered saprotrophic, associated with the wood of diseased grapevines has increased interest in this family. The diversity of tropical species is less well known and more poorly sampled in phylogenetic studies than temperate species. In the present study, we investigated the diversity of diatrypaceous fungi from three areas in the Brazilian semi-arid region and performed phylogenetic analyses of the family based on the entire internal transcribed spacer (ITS) region and partial s-tubulin gene. Twenty-eight new ITS and 19 new s-tubulin sequences were generated, representing eight species distributed in five clades. Diatrypella atlantica, Eutypa guttulata, Eutypella cearensis, and Peroneutypa diminutispora are proposed here as new species, while Eutypella microtheca and P. curvispora are new records for Brazil. All eight species are described, illustrated, and discussed.

Diatrypella macrospora sp. nov. and new records of diatrypaceous fungi from Iran

Descriptions and illustrations are provided for six diatrypaceous species from Iran. Diatrypella macrospora is introduced as new to science. It differs from all other Diatrypella species by its larger ascospores. New records for the Iranian mycota include Cryptovalsa rabenhorstii, Eutypella citricola, Peroneutypa scoparia and Quaternaria quaternata. Descriptions and illustrations of microscopic characters, ITS sequence data and taxonomic notes are provided for these newly reported taxa.

Diatrypaceous fungi in north-eastern China. 1. Cryptosphaeria and Diatrype

The paper considers 13 species belonging to the genera Diatrype and Cryptosphaeria (Diatrypaceae) found in north-eastern China (Heilongjiang and Jilin Provinces). Cryptosphaeria nigrescens and Diatrype sinensis are described as new species. Four species recorded are only known from the area around the Sea of Japan, three other species display a biogeographical pattern known as ‘Asa Gray disjunction’, and two species are reported far from their main findings in Europe.

Plant-fungal association in trees: Insights into changes in ecological strategies of Peroneutypa scoparia (Diatrypaceae)

Fungal endophytes comprise a highly diverse group of particular interest for their relevant implications to the ecosystems they inhabit. The objective of this study was to infer the phylogenetic affinity between strains of Peroneutypa scoparia exhibiting different lifestyles to elucidate possible shifts in ecological roles. Specimens and living cultures used in the present study were obtained from decaying wood and from live stem tissues of the invasive host species Broussonetia papyrifera. The similarity between the fungal strains was studied through molecular analyses. The results showed a close phylogenetic link and high genetic similarity between endophytic and saprotrophic strains. The main findings suggest that P. scoparia has primary access to the substrate as an endophyte and then this organism may change its use of the available resources presenting a saprotrophic growth. These results provide valuable information about the roles that diatrypaceous fungi play as endophytes or as decaying wood inhabitants and contributes to evaluate the ecological significance of this group.

Pathogenicity of Diatrypaceous Fungi on Grapevines in Australia.

In addition to Eutypa lata, which causes Eutypa dieback, numerous other fungi in the Diatrypaceae family have been isolated from diseased grapevines (Vitis vinifera) and other woody hosts. Pathogenicity trials comprising 70 strains of diatrypaceous fungi representing nine species in six genera were conducted to determine whether these fungi, collected in Australia, were pathogenic to grapevines. When inoculated into wounded trunks of 'Cabernet Sauvignon', eight species, including E. lata, E. leptoplaca, Cryptovalsa ampelina, C. rabenhorstii, Eutypella citricola, E. microtheca, Diatrypella vulgaris, and a Diatrype sp. produced necrotic lesions significantly longer than on controls. In addition, all nine species (including a Cryptosphaeria sp.) were reisolated from the margins of developing lesions and at varying distances above and below the point of inoculation. Diatrypaceous fungi were frequently isolated from asymptomatic or otherwise healthy tissue several centimeters ahead of the disease margin. Methods to control diseases associated with diatrypaceous fungi must take into account their propensity to colonize woody tissues ahead of or in the absence of visible symptoms. Current recommendations for the management of Eutypa dieback using remedial surgery and pruning wound protection appear sufficient for the control of the other diatrypaceous fungi included in this study.

Efficacy of fungicides on mycelial growth of diatrypaceous fungi associated with grapevine trunk disease

Several species of Diatrypaceae have been recently isolated from the wood of cankered grapevines in several regions of the world and shown to be pathogenic with varying degrees of virulence when inoculated in stems of potted vines. Existing management strategies have focussed on the development of procedures and products to prevent or reduce Eutypa lata infection. The best method to prevent infection is by applying fungicides to wounds, but there are few registered chemicals for any of the diatrypaceous fungi in Australia. Six selected fungicides were evaluated in vitro for their efficacy in reducing mycelial growth of Eutypa lata, Cryptovalsa ampelina, Diatrypella vulgaris, Eutypa leptoplaca, Eutypella citricola and Eutypella microtheca. Carbendazim, fluazinam, tebuconazole, and prothioconazole + tebuconazole were effective at inhibiting mycelial growth of all Diatrypaceae spp. tested. Pyraclostrobin reduced colony diameter of most of the fungal species by 50% or more. Pyrimethanil was ineffective at reducing mycelial growth of these pathogens. Five of the six fungicides evaluated in this study have shown efficacy in vitro against Diatrypaceae spp. and require further evaluation in the field. This study represents the first approach for fungicide evaluation against mycelial growth of diatrypaceous fungi, other than Ea. lata. It contributes to the development of integrated management strategies for grapevine trunk diseases.

Taxonomy and DNA phylogeny of Diatrypaceae associated with Vitis vinifera and other woody plants in Australia

The Diatrypaceae occur worldwide and comprise a number of pathogens of woody crops, forest and ornamental tree species. Despite the taxonomic difficulties within this family, interest in the Diatrypaceae has increased recently, mainly due to the recent detection of these fungi in the premium grape growing regions of California. In the present study, we investigated the diversity and host range of diatrypaceous fungi from prominent wine grape growing regions in South Australia, New South Wales and Western Australia. Approximately 100 isolates were collected from grapevine and other woody plants and compared with reference collections from the United States and Europe. Phylogenetic analyses of the complete sequence of the internal transcribed spacer (ITS) region of the ribosomal DNA and partial sequence of the β-tubulin gene, combined with morphological analyses separated 12 species. These included the previously described species Cryptovalsa ampelina, C. rabenhorstii, Diatrype brunneospora, Eutypa lata, E. leptoplaca, Eutypella australiensis, E. citricola, a Cryptosphaeria sp. and a Diatrype sp., whereas Diatrypella vulgaris, Eutypella cryptovalsoidea and E. microtheca are described as new. Seven species were isolated from grapevine but the prevalence of Diatrypaceae in grapevine cankers varied among the regions surveyed. In many instances in WA and NSW, these newly reported fungi were more widespread and abundant than E. lata. This study provides new information to assist with diagnosis of the causal agents of dieback and canker diseases in Australia and development of management strategies. Further studies to characterize the pathogenicity of diatrypaceous species to grapevines and to elucidate the biology of these fungi are underway.

Pathogenicity of Diatrypaceae Species in Grapevines in California.

Diatrypaceous fungi have been isolated from cankered wood of grapevines (Vitis vinifera) in California. However, the pathogenicity of these fungi and their potential to cause diseases in grapevine was unknown. A series of pathogenicity tests were conducted to determine if these fungi were grapevine pathogens. In all experiments, species of the family Diatrypaceae were re-isolated from the margins of developing lesions, although frequency of re-isolation and average length of vascular discolorations varied among isolates. Cryptovalsa ampelina, Diatrype stigma, and Eutypa leptoplaca were capable of colonizing dormant canes and causing vascular necrosis. Cryptosphaeria pullmanensis, C. ampelina, D. stigma, Diatrype whitmanensis, and E. leptoplaca infected and caused lesions in green shoots of the new vegetative growth. Diatrype oregonensis and Diatrypella verrucaeformis isolates did not produce lesions that were significantly different from those produced in the control shoots and canes. This suggests that D. oregonensis and D. verrucaeformis fungi may be saprophytic rather than pathogenic to grapevine.

Diversity of diatrypaceous fungi associated with grapevine canker diseases in California

Eutypa lata is the most common diatrypaceous fungus in grapevine cankers. This study was undertaken to determine the presence and diversity of other members of the Diatrypaceae in grapevines in California. We isolated into pure culture 11 species of Diatrypaceae from the wood of diseased grapevines including Cryptosphaeria pullmanensis, Cryptovalsa ampelina, Diatrype oregonensis, D. stigma, D. whitmanensis, Diatrype sp., Diatrypella verrucaeformis and four putative species of Eutypella. Species were identified or grouped morphologically and by phylogenetic analyses of the complete sequence of the internal transcribed spacer (ITS) of the rDNA and β-tubulin gene. Diatrypaceous fungi also occurred frequently on the native flora surrounding vineyards, thus serving as possible inoculum sources for these putative pathogens.

Identification, Incidence, and Pathogenicity of Fungal Species Associated with Grapevine Dieback in Texas

Grapevine cankers and consequent dieback have been commonly observed in Texas vineyards. However, identity of the grapevine canker-causing agents in Texas has not been reported. Between 2007 and 2009, diseased grapevine samples showing perennial cankers from 45 vineyards in Texas were collected and inspected for fungal identification. Eleven fungal species—<i>Lasiodiplodia theobromae</i>, <i>Botryosphaeria dothidea</i>, <i>Neofusicoccum parvum</i>, <i>Diplodia seriata</i>, <i>Diplodia corticola</i>, <i>Phomopsis viticola</i>, <i>Eutypella vitis</i>, <i>Diatrypella</i> sp., <i>Truncatella</i> sp., <i>Pestalotiopsis uvicola</i>, and <i>Pestalotiopsis</i> sp.—were isolated from grapevine cankers and identified based on morphological characteristics and analyses of nucleotide sequences of the internal transcribed spacer region (ITS1-5.8S-ITS2). Botryosphaeriaceae spp. were the most common fungi isolated from grapevine dieback in Texas followed by <i>Pestalotiopsis</i> spp., <i>P. viticola</i>, and Diatrypaceae spp. Pathogenicity of all species was verified by inoculation of excised mature lignified dormant canes of Redglobe and Cabernet Sauvignon grapevines under controlled laboratory conditions. Isolates of <i>L. theobromae</i> and <i>N. parvum</i> were the most virulent based on the length of vascular necrosis in the wood and percentage of fungal re-isolation. <i>Phomopsis viticola</i> isolates followed in virulence to <i>L. theobromae</i> and <i>N. parvum</i> and were shown to be capable of colonizing mature wood and cause vascular necrosis and cankers. The diatrypaceous fungi <i>E. vitis</i> and <i>Diatrypella</i> sp. were the least virulent to grapevines among all fungi tested. All these fungal species represent newly recorded fungal pathogens of grapevines in Texas. Moreover, the association of <i>D. corticola</i> with grapevines is reported.

Detection ofEutypa lataandEutypella vitisin Grapevine by Nested Multiplex Polymerase Chain Reaction

ABSTRACT Two fungi were isolated from grapevines in Michigan vineyards with Eutypa dieback symptoms: Eutypa lata and Eutypella vitis. These fungi are difficult to distinguish morphologically but are genetically distinct as determined by sequencing of the internal transcribed spacer (ITS) regions. The ITS regions of 25 Eutypa lata and 15 Eutypella vitis isolates were sequenced. Eutypa lata sequences were more variable than those of Eutypella vitis. Polymerase chain reaction (PCR) primers were designed for each species and evaluated against isolates of both fungi as well as 11 closely related Diatrypaceous fungi and 23 isolates of other fungi representing various pathogenic, saprophytic, and endophytic genera on grape and other small fruit crops. The primers were specific for their intended species. A nested multiplex PCR protocol was developed and used to successfully detect these fungi in wood samples from cankers with and without stromata from naturally infected vines as well as in artificially inoculated, potted canes. The primers developed in this study will assist in our abilities to diagnose and study the roles of Eutypa lata and Eutypella vitis in Eutypa dieback development.

Identification of Eutypa lata by PCR-RFLP.

Eutypa lata is a vascular canker pathogen of woody plants commonly diagnosed by isolating the pathogen from infected tissue. Related fungi from the same family, the Diatrypaceae, also have been found in association with grapevine in Californian vineyards. An in situ polymerase chain reaction (PCR) method has been developed for detection of E. lata in infected wood tissue. However, our results indicate that this method also would amplify other Diatrypaceous fungi, which could potentially lead to an incorrect diagnosis. Therefore, we developed a PCR-restriction fragment length polymorphism (PCR-RFLP) assay. The internal transcribed spacer (ITS)1/5.8S/ITS2 ribosomal DNA region was amplified by PCR using universal primers, and RFLP patterns were determined after digestion with AluI. The restriction profiles obtained served to distinguish E. lata from wood trunk pathogens of grapevine (Phomopsis viticola, Botryodiplodia sp., Phaeoacremonium aleophilum, and Phaeomoniella chlamydospora), Diatrypaceous fungi (Diatrype sp., Diatrypella sp., Eutypella vitis, and Eutypa leptoplaca), and Cryptovalsa sp. found on dead wood of grapevine, and other Eutypa spp. (E.petrakii var. hederae, E. astroidea, E. crustata, and E. lejoplaca), with the exception of E. armeniacae, which we regard as a synonym for E. lata, and E. laevata, which has not been found on grapevine.

Conidial Nuclei in three Species of Diatrypaceae and Diaporthe Vaccinii

Morphology of conidial nuclei in Cryptosphaeria populina, Eutypella vitis, and Diatrype stigma was studied and compared with that of nuclei in conidia of Diaporthe vaccinii. Giemsa and DAPI stains revealed that the diatrypaceous conidial nuclei were elongate and centrally located, often occupying a large cellular volume. Diaporthe vaccinii beta conidial nuclei were shorter and located near the basal ends of spores, while those of alpha conidia were ovoid and usually in the central regions of the spores. Similarities between conidial nuclei of diatrypaceous and xylariaceous fungi are noted. The significance of these findings in relation to the taxonomy of the Diatrypaceae, Xylariaceae, and Diaporthales is discussed.