scholarly journals A Novel Fusarium Species Causes a Canker Disease of the Critically Endangered Conifer, Torreya taxifolia

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 633-639 ◽  
Author(s):  
Jason A. Smith ◽  
Kerry O'Donnell ◽  
Lacey L. Mount ◽  
Keumchul Shin ◽  
Kelly Peacock ◽  
...  
Keyword(s):  
Fusarium Species ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Causal Agent ◽  
Its Rdna ◽  
Critically Endangered ◽  
Internal Transcribed Spacer Region ◽  
Canker Disease ◽  
Critically Endangered Species ◽  
Rdna Sequences

A canker disease of Florida torreya (Torreya taxifolia) has been implicated in the decline of this critically endangered species in its native range of northern Florida and southeastern Georgia. In surveys of eight Florida torreya sites, cankers were present on all dead trees and 71 to 100% of living trees, suggesting that a fungal pathogen might be the causal agent. To identify the causal agent, nuclear ribosomal internal transcribed spacer region (ITS rDNA) sequences were determined for 115 fungi isolated from cankers on 46 symptomatic trees sampled at three sites in northern Florida. BLASTn searches of the GenBank nucleotide database, using the ITS rDNA sequences as the query, indicated that a novel Fusarium species designated Fsp-1 might be the etiological agent. Molecular phylogenetic analyses of partial translation elongation factor 1-alpha (EF-1) and RNA polymerase second largest subunit (RPB2) gene sequences indicate that Fsp-1 represents a novel species representing one of the earliest divergences within the Gibberella clade of Fusarium. Results of pathogenicity experiments established that the four isolates of Fsp-1 tested could induce canker symptoms on cultivated Florida torreya in a growth chamber. Koch's postulates were completed by the recovery and identification of Fsp-1 from cankers of the inoculated plants.

Fungal Pathogens Associated With Canker Diseases of Almond in California

Plant Disease ◽  
2020 ◽  
pp. PDIS-10-19-2128
Author(s):  
Leslie A. Holland ◽  
Florent P. Trouillas ◽  
Mohamed T. Nouri ◽  
Daniel P. Lawrence ◽  
Maria Crespo ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Central Valley ◽  
Disease Diagnosis ◽  
Mature Trees ◽  
Internal Transcribed Spacer Region ◽  
Canker Disease ◽  
Eutypa Lata ◽  
Almond Orchards

Almond canker diseases are destructive and can reduce the yield as well as the lifespan of almond orchards. These diseases may affect the trunk and branches of both young and mature trees and can result in tree death soon after orchard establishment in severe cases. Between 2015 and 2018, 70 almond orchards were visited throughout the Central Valley of California upon requests from farm advisors for canker disease diagnosis. Two major canker diseases were identified, including Botryosphaeriaceae cankers and Ceratocystis canker. In addition, five less prevalent canker diseases were identified, including Cytospora, Eutypa, Diaporthe, Collophorina, and Pallidophorina canker. Seventy-four fungal isolates were selected for multilocus phylogenetic analyses of internal transcribed spacer region ITS1-5.8S-ITS2 and part of the translation elongation factor 1-α, β-tubulin, and glyceraldehyde 3-phosphate dehydrogenase gene sequences; 27 species were identified, including 12 Botryosphaeriaceae species, Ceratocystis destructans, five Cytospora species, Collophorina hispanica, four Diaporthe species, two Diatrype species, Eutypa lata, and Pallidophorina paarla. The most frequently isolated species were Ceratocystis destructans, Neoscytalidium dimidiatum, and Cytospora californica. Pathogenicity experiments on almond cultivar Nonpareil revealed that Neofusicoccum parvum, Neofusicoccum arbuti, and Neofusicoccum mediterraneum were the most virulent. Botryosphaeriaceae cankers were predominantly found in young orchards and symptoms were most prevalent on the trunks of trees. Ceratocystis canker was most commonly found in mature orchards and associated with symptoms found on trunks or large scaffold branches. This study provides a thorough examination of the diversity and pathogenicity of fungal pathogens associated with branch and trunk cankers of almond in California.

Generic classification of some more hyphomycetes with solitary conidia borne on phialides

1998 ◽  
Vol 76 (9) ◽  
pp. 1570-1583 ◽  
Author(s):  
W Gams ◽  
K O'Donnell ◽  
H -J Schroers ◽  
M Christensen
Keyword(s):  
New Species ◽  
Phylogenetic Analyses ◽  
Large Subunit ◽  
Elongation Factor ◽  
28S Rdna ◽  
New Combination ◽  
Rdna Sequences ◽  
28S Rdna Sequences ◽  
Three New Species ◽  
Morphological Species

Unlike most phialide-producing fungi that liberate a multiplicity of conidia from each conidiogenous cell, only single conidia are formed on phialide-like conidiogenous cells in Aphanocladium, Verticimonosporium, and some species of Sibirina. A group of isolates obtained from soil of native Artemisia tridentata (sagebrush) grassland in Wyoming and from desert soil in Iraq is compared with these genera and classified as a fourth genus, Stanjemonium, honouring Stanley J. Hughes. Phylogenetic analyses of partial nuclear small- (18S) and large-subunit (28S) rDNA sequences indicate that Stanjemonium spp. form a monophyletic group with Emericellopsis. Sequences from the nuclear 18S and 28S rDNA were too conserved to resolve morphological species of Stanjemonium; however, phylogenetic analysis of b-tubulin and translation elongation factor 1a gene exons and introns resolved all species distinguished morphologically. Numerous conidiogenous cells or denticles are scattered along the cells of aerial hyphae in Aphanocladium and Stanjemonium spp., very rapidly collapsing into denticles in the former, somewhat more persistent and leaving broad scars in the latter. In Cladobotryum-Sibirina and Verticimonosporium spp., conidiogenous cells are discrete in terminal and intercalary whorls; phialides of the latter taxon are particularly swollen. The taxonomy of Aphanocladium is not yet resolved. Two species are recognized in Verticimonosporium. Three new species of Stanjemonium are described, and one new combination from Aphanocladium is proposed, along with one new species of Cladobotryum.Key words: Aphanocladium, Cladobotryum, conidiogenesis, hyphomycetes, molecular phylogeny, phialide, Stanjemonium, systematics, Verticimonosporium.

Molecular identification of cyst-forming nematodes (Heteroderidae) from Iran and a phylogeny based on ITS-rDNA sequences

Nematology ◽  
2003 ◽  
Vol 5 (1) ◽  
pp. 99-111 ◽  
Author(s):  
Zahra Tanha Maafi ◽  
Sergei Subbotin ◽  
Maurice Moens
Keyword(s):  
Phylogenetic Analyses ◽  
Species Level ◽  
Its Rdna ◽  
Heterodera Avenae ◽  
Published Data ◽  
Rdna Sequences ◽  
First Time ◽  
Group Species ◽  
High Support ◽  
Different Parts

Abstract RFLP and sequences of ITS-rDNA of 45 populations of cyst-forming nematodes collected from different parts of Iran were analysed and identified as representatives of 21 species. Eight enzymes generated RFLP for all studied populations. Comparison of RFLP profiles and sequences of the ITS regions with published data confirmed the presence of Heterodera avenae, H. filipjevi, H. glycines, H. hordecalis, H. latipons, H. schachtii and H. trifolii in Iran. RFLP patterns and ITS sequences for H. elachista, H. turcomanica, H. mothi and C. cacti were obtained for the first time in this study. Heterodera humuli, H. goettingiana, H. fici, H. elachista, H. turcomanica and Cactodera cacti are recorded for the first time in Iran. These results correspond with morphological and morphometric identification of the populations. Several populations were not identified at the species level and are attributed to Heterodera sp.; some of these may correspond to new species. Twenty-one new sequences from Iranian cyst-forming nematodes and 36 known sequences were used for the phylogenetic analyses. The cyst-forming nematodes formed several clades corresponding to their morphological features. Heterodera mothi and H. elachista clustered with high support with other Cyperi group species and H. turcomanica formed a moderately to highly supported clade with the Humuli group.

Amanita submelleialba sp. nov. in section Amanita from northern Thailand

Phytotaxa ◽  
2021 ◽  
Vol 513 (2) ◽  
pp. 129-140
Author(s):  
YUAN S. LIU ◽  
JIAN-KUI LIU ◽  
PETER E. MORTIMER ◽  
SAISAMORN LUMYONG
Keyword(s):  
Rna Polymerase Ii ◽  
Phylogenetic Analyses ◽  
Line Drawing ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Nuclear Rdna ◽  
Internal Transcribed Spacer Region ◽  
Northern Thailand ◽  
Extant Species ◽  
Distinct Lineage

Amanita submelleialba sp. nov. in section Amanita, is described from northern Thailand based on both multi-gene phylogenetic analysis and morphological evidences. It is characterized by having small to medium-sized basidiomata; a yellow to yellowish pale pileus covering pyramidal to subconical, white to yellow white volval remnants; globose stipe base covered conical, white to yellow white volval remnants; fugacious subapical annulus; and absent clamps. Multi-gene phylogenetic analyses based on partial nuclear rDNA internal transcribed spacer region (ITS), partial nuclear rDNA larger subunit region (nrLSU), RNA polymerase II second largest subunit (RPB2), partial translation elongation factor 1-alpha (TEF1-α) and beta-tubulin gene (TUB) indicated that A. submelleialba clustered together with A. elata and A. mira, but represented as a distinct lineage from other extant species in section Amanita. The detailed morphological characteristics, line-drawing illustration and comparisons with morphologically similar taxa are provided.

Identification of Photobionts from the lichen family Physciaceae using algal-specific ITS rDNA sequencing

2001 ◽  
Vol 33 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Gert Helms ◽  
Thomas Friedl ◽  
Gerhard Rambold ◽  
Helmut Mayrhofer
Keyword(s):  
Phylogenetic Analyses ◽  
Pcr Primers ◽  
Its Rdna ◽  
Generic Level ◽  
Sequence Comparisons ◽  
Its Phylogeny ◽  
Specific Pcr ◽  
Rdna Sequences ◽  
Rdna Sequencing ◽  
Geographical Regions

AbstractThe identity of photobionts from 20 species of the Physciaceae from different habitats and geographical regions has been determined by ITS rDNA sequence comparisons in order to estimate the diversity of photobionts within that lichen group, to detect patterns of specificity of mycobionts towards their photobionts and as a part of an ongoing study to investigate possible parallel cladogenesis of both symbionts. Algal-specific PCR primers have been used to determine the ITS rDNA sequences from DNA extractions of dried lichens that were up to 5 years old. Direct comparisons and phylogenetic analyses allowed the assignment of Physciaceae photobionts to four distinct clades in the photobiont ITS rDNA phylogeny. The results indicate a diversity within the genus Trebouxia Puymaly and Physciaceae photobionts that is higher than expected on the basis morphology alone. Physciaceae photobionts belonged to 12 different ITS lineages of which nine could unambiguously be assigned to six morphospecies of Trebouxia. The identity of the remaining three sequences was not clarified; they may represent new species. Specificity at the generic level was low as a whole range of photobiont species were found within a genus of Physciaceae and different ranges were detected. The photobionts of Physcia (Schreb.) Michaux were closely related and represented one morphospecies of Trebouxia, whereas the algal partners of Buellia De Not and Rinodina (Ach.) Gray were in distant lineages of the ITS phylogeny and from several Trebouxia morphospecies. Photobiont variation within a genus of Physciaceae may be due to phylogeny, geographical distance or because photobionts from neighbouring lichens were taken (“algal sharing“). At the species level Physciaceae mycobionts seem to be rather selective and contained photobionts that were very closely related within one morphospecies of Trebouxia.

scholarly journals Phomopsis Stem Canker: A Reemerging Threat to Sunflower (Helianthus annuus) in the United States

2015 ◽  
Vol 105 (7) ◽  
pp. 990-997 ◽  
Author(s):  
Febina M. Mathew ◽  
Kholoud M. Alananbeh ◽  
James G. Jordahl ◽  
Scott M. Meyer ◽  
Lisa A. Castlebury ◽  
...  
Keyword(s):  
United States ◽  
Helianthus Annuus ◽  
Great Plains ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Stem Canker ◽  
The United States ◽  
Northern Great Plains ◽  
Type Specimens ◽  
Internal Transcribed Spacer Region

Phomopsis stem canker causes yield reductions on sunflower (Helianthus annuus L.) on several continents, including Australia, Europe, and North America. In the United States, Phomopsis stem canker incidence has increased 16-fold in the Northern Great Plains between 2001 and 2012. Although Diaporthe helianthi was assumed to be the sole causal agent in the United States, a newly described species, D. gulyae, was found to be the primary cause of Phomopsis stem canker in Australia. To determine the identity of Diaporthe spp. causing Phomopsis stem canker in the Northern Great Plains, 275 infected stems were collected between 2010 and 2012. Phylogenetic analyses of sequences of the ribosomal DNA internal transcribed spacer region, elongation factor subunit 1-α, and actin gene regions of representative isolates, in comparison with those of type specimens, confirmed two species (D. helianthi and D. gulyae) in the United States. Differences in aggressiveness between the two species were determined using the stem-wound method in the greenhouse; overall, D. helianthi and D. gulyae did not vary significantly (P ≤ 0.05) in their aggressiveness at 10 and 14 days after inoculation. These findings indicate that both Diaporthe spp. have emerged as sunflower pathogens in the United States, and have implications on the management of this disease.

Root Rot Caused by Species of Fusarium on Brassica carinata in South Dakota

2018 ◽  
Vol 19 (3) ◽  
pp. 188-192
Author(s):  
Paul N. Okello ◽  
Kristina Petrović ◽  
Brian Kontz ◽  
Shaukat Ali ◽  
Laura F. Marek ◽  
...  
Keyword(s):  
South Dakota ◽  
Root Rot ◽  
Rating Scale ◽  
Fusarium Species ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
The United States ◽  
Brassica Carinata ◽  
Oilseed Crop ◽  
Root Diseases

Brassica carinata is an emerging oilseed crop in the United States, and root diseases caused by Fusarium have the potential to cause yield losses in production. In this study, B. carinata plants were randomly sampled at vegetative and seed development plant stages from South Dakota State University experimental plots. Reddish-brown lesions were observed on roots of sampled plants from which F. acuminatum, F. oxysporum, F. solani, and F. sporotrichioides were recovered. The Fusarium species were identified based on morphology and phylogenetic analyses of the translation elongation factor 1-α gene region. Pathogenicity of the four Fusarium species was evaluated on five B. carinata accessions using a modified inoculum layer method in the greenhouse. At 21 days after inoculation, root rot severity caused by Fusarium on the B. carinata accessions was assessed on a rating scale of 0 to 4 and evaluated using relative treatment effects (RTEs). The F. oxysporum isolate caused significant differences in RTE (P = 0.01) among the B. carinata accessions. However, there were no significant differences in RTE among the B. carinata accessions in response to F. acuminatum (P = 0.82), F. solani (P = 0.76), and F. sporotrichioides (P = 0.47) isolates.

scholarly journals A Survey of Trunk Disease Pathogens within Citrus Trees in Iran

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 754
Author(s):  
Nahid Espargham ◽  
Hamid Mohammadi ◽  
David Gramaje
Keyword(s):  
Sequence Data ◽  
Fusarium Species ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Nuclear Ribosomal Dna ◽  
Internal Transcribed Spacer Region ◽  
Lasiodiplodia Theobromae ◽  
Dna Sequence Data ◽  
Pathogenicity Tests ◽  
Citrus Trees

Citrus trees with cankers and dieback symptoms were observed in Bushehr (Bushehr province, Iran). Isolations were made from diseased cankers and branches. Recovered fungal isolates were identified using cultural and morphological characteristics, as well as comparisons of DNA sequence data of the nuclear ribosomal DNA-internal transcribed spacer region, translation elongation factor 1α, β-tubulin, and actin gene regions. Dothiorella viticola, Lasiodiplodia theobromae, Neoscytalidium hyalinum, Phaeoacremonium (P.) parasiticum, P. italicum, P. iranianum, P. rubrigenum, P. minimum, P. croatiense, P. fraxinopensylvanicum, Phaeoacremonium sp., Cadophora luteo-olivacea, Biscogniauxia (B.) mediterranea, Colletotrichum gloeosporioides, C. boninense, Peyronellaea (Pa.) pinodella, Stilbocrea (S.) walteri, and several isolates of Phoma, Pestalotiopsis, and Fusarium species were obtained from diseased trees. The pathogenicity tests were conducted by artificial inoculation of excised shoots of healthy acid lime trees (Citrus aurantifolia) under controlled conditions. Lasiodiplodia theobromae was the most virulent and caused the longest lesions within 40 days of inoculation. According to literature reviews, this is the first report of L. theobromae and N. hyalinum on citrus in Iran. Additionally, we report several Phaeoacremonium species, S. walteri, Pa. pinodella and C. luteo-olivacea on citrus trees for the first time in the world.

Fusarium spp. associated with root rot of pulse crops and their cross pathogenicity to cereal crops in Montana

Plant Disease ◽  
2020 ◽  
Author(s):  
Swarnalatha Moparthi ◽  
Mary Eileen Burrows ◽  
Josephine Mgbechi-Ezeri ◽  
Bright Agindotan
Keyword(s):  
Root Rot ◽  
Fusarium Species ◽  
Elongation Factor ◽  
Abundant Species ◽  
Cereal Crops ◽  
Fusarium Spp ◽  
Internal Transcribed Spacer Region ◽  
Translation Elongation ◽  
Pulse Crops ◽  
Disease Management Strategy

Root rot caused by Fusarium species is a major problem in the pulse growing regions of Montana. Fusarium isolates (n=112) were obtained from seeds and/or roots of chickpea, dry pea, and lentil. Isolates were identified by comparing the sequences of the internal transcribed spacer region and the translation elongation factor 1-α in Fusarium-ID database. Fusarium avenaceum was the most abundant species (28%), followed by F. acuminatum (21%), F. poae (13%), F. oxysporum (8%), F. culmorum (6%), F. redolens (6%), F. sporotrichioides (6%), F. solani (4%), F. graminearum (2%), F. torulosum (2%) and F. tricinctum (0.9%). The aggressiveness of a subset of 50 isolates that represent various sources of isolation was tested on three pulse crops and two cereal crops. Nonparametric analysis of variance conducted on ranks of disease severity indicated that F. avenaceum and F. solani isolates were highly aggressive on pea and chickpea. In lentil, F. avenaceum and F. culmorum were highly aggressive. In barley, F. avenaceum, F. solani, F. culmorum, and F. graminearum were highly aggressive. In wheat, F. avenaceum, F. graminearum, and F. culmorum were highly aggressive. Two F. avenaceum isolates were highly aggressive across all the crops tested and found to be cross pathogenic. One isolate of F. culmorum and an isolate of F. graminearum obtained from chickpea and lentil seed were highly aggressive on barley and wheat. The results indicate that multiple Fusarium spp. from seeds and roots can cause root rot on both pulse and cereal crops. Rotating these crops may still lead to an increase in inoculum levels, making crop rotation limited in efficacy as a disease management strategy.

scholarly journals Molecular Characterization and Disease Control of Stem Canker on Royal Poinciana (Delonix regia) Caused by Neoscytalidium dimidiatum in the United Arab Emirates

2020 ◽  
Vol 21 (3) ◽  
pp. 1033
Author(s):  
Seham M. Al Raish ◽  
Esam Eldin Saeed ◽  
Arjun Sham ◽  
Khulood Alblooshi ◽  
Khaled A. El-Tarabily ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Stem Canker ◽  
Canker Disease ◽  
Delonix Regia ◽  
Neoscytalidium Dimidiatum ◽  
Morphological Studies ◽  
Advanced Stages ◽  
Reference Specimens

In the United Arab Emirates (UAE), royal poinciana (Delonix regia) trees suffer from stem canker disease. Symptoms of stem canker can be characterized by branch and leaf dryness, bark lesions, discoloration of xylem tissues, longitudinal wood necrosis and extensive gumming. General dieback signs were also observed leading to complete defoliation of leaves and ultimately death of trees in advanced stages. The fungus, Neoscytalidium dimidiatum DSM 109897, was consistently recovered from diseased royal poinciana tissues; this was confirmed by the molecular, structural and morphological studies. Phylogenetic analyses of the translation elongation factor 1-a (TEF1-α) of N. dimidiatum from the UAE with reference specimens of Botryosphaeriaceae family validated the identity of the pathogen. To manage the disease, the chemical fungicides, Protifert®, Cidely® Top and Amistrar® Top, significantly inhibited mycelial growth and reduced conidial numbers of N. dimidiatum in laboratory and greenhouse experiments. The described “apple bioassay” is an innovative approach that can be useful when performing fungicide treatment studies. Under field conditions, Cidely® Top proved to be the most effective fungicide against N. dimidiatum among all tested treatments. Our data suggest that the causal agent of stem canker disease on royal poinciana in the UAE is N. dimidiatum.

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