scholarly journals A Reassessment of the Species Concept in Eutypa lata, the Causal Agent of Eutypa Dieback of Grapevine

2006 ◽  
Vol 96 (4) ◽  
pp. 369-377 ◽  
Author(s):  
P. E. Rolshausen ◽  
N. E. Mahoney ◽  
R. J. Molyneux ◽  
W. D. Gubler
Keyword(s):  
Species Concept ◽  
Phylogenetic Analyses ◽  
Distinct Species ◽  
Causal Agent ◽  
Internal Transcribed Spacer Region ◽  
Eutypa Lata ◽  
The Third ◽  
Eutypa Dieback ◽  
Morphological Differences ◽  
Branch Dieback

Eutypa dieback is a vascular disease of several cultivated crops and trees worldwide. The attribution of the name to the agent responsible for branch dieback is ambiguous. Pathogenicity of Eutypa sp. first was reported on apricot and the causal agent was named E. armeniacae. However, no morphological differences were reported with the previously described E. lata, and some authors considered both species synonymous. Others regarded them as distinct species on the basis of pathogenesis and molecular analysis. We further investigated the relatedness of both species by phylogenetic analyses of the internal transcribed spacer region and β-tubulin gene. These analyses included several other taxa placed in the same family (Diatrypaceae), and yielded three groups. The isolates referred to as E. lata in previous work clustered with Diatrype stigma in one group. Isolates of E. armeniacae and E. lata clustered in a second group, supporting the synonymy of these species. The third group included other Eutypa spp. supporting the polyphyletic origin of this genus. Measurements of conidia length and secondary metabolite production of isolates supported the phylogenetic analyses. Secondary metabolites appeared to be a synapomorphic character shared by several taxa including E. lata, E. armeniacae, E. laevata, and E. petrakii var. petrakii.

scholarly journals Eutypa, Eutypella, and Cryptovalsa Species (Diatrypaceae) Associated with Prunus Species in South Africa

Plant Disease ◽  
2018 ◽  
Vol 102 (7) ◽  
pp. 1402-1409 ◽  
Author(s):  
Providence Moyo ◽  
Ulrike Damm ◽  
Lizel Mostert ◽  
Francois Halleen
Keyword(s):  
South Africa ◽  
Phylogenetic Analyses ◽  
Fruit Trees ◽  
Fungal Species ◽  
Stone Fruit ◽  
Prunus Species ◽  
Internal Transcribed Spacer Region ◽  
Eutypa Lata ◽  
Eutypa Dieback ◽  
Prunus Spp

Stone fruit trees (Prunus spp.) are economically important fruit trees cultivated in South Africa. These trees are often grown in close proximity to vineyards and are to a large extent affected by the same trunk disease pathogens as grapevines. The aim of the present study was to determine whether stone fruit trees are inhabited by Diatrypaceae species known from grapevines and whether these trees could act as alternative hosts for these fungal species. Isolations were carried out from symptomatic wood of Prunus species (almond, apricot, cherry, nectarine, peach, and plum) in stone fruit growing areas in South Africa. Identification of isolates was based on phylogenetic analyses of the internal transcribed spacer region and β-tubulin gene. Forty-six Diatrypaceae isolates were obtained from a total of 380 wood samples, from which five species were identified. All five species have also been associated with dieback of grapevine. The highest number of isolates was found on apricot followed by plum. No Diatrypaceae species were isolated from peach and nectarine. Eutypa lata was the dominant species isolated (26 isolates), followed by Cryptovalsa ampelina (7), Eutypa cremea (5), Eutypella citricola (5), and Eutypella microtheca (3). First reports from Prunus spp. are E. cremea, E. citricola, and E. microtheca. Pathogenicity tests conducted on apricot and plum revealed that all these species are pathogenic to these hosts, causing red-brown necrotic lesions like those typical of Eutypa dieback on apricot.

Morphological and molecular characterization of two species of Gelidium (Gelidiales, Rhodophyta) from Mexico: G. nayaritense sp. nov. and the new record of G. sanyaense

Phytotaxa ◽  
2021 ◽  
Vol 527 (3) ◽  
pp. 161-176
Author(s):  
NATALY QUIROZ-GONZÁLEZ ◽  
MA. EDITH PONCE-MÁRQUEZ ◽  
NORMA LÓPEZ-GÓMEZ ◽  
DENÍ RODRÍGUEZ
Keyword(s):  
Gulf Of California ◽  
Phylogenetic Analyses ◽  
Distinct Species ◽  
Tropical Region ◽  
Mexican Pacific ◽  
Molecular Approaches ◽  
Diagnostic Characteristics ◽  
Morphological Differences ◽  
First Time

Gelidium pusillum is a species reported from the northern Gulf of California to the tropical region of the Mexican Pacific, but there is wide morphological variation among populations. The objective of this research was to evaluate of the Mexican species using morphological and molecular approaches, with the markers rbcL and COI-5P. This study examined 12 samples from four sites in the Mexican tropical Pacific. Phylogenetic analyses resolved these specimens within two clades separated from the topotype material of G. pusillum. The main morphological differences with other Mexican and phylogenetic closely related species were size, branching pattern, branching order, distribution of internal rhizoidal filaments, and shape of the tetrasporangial sori. The sequence divergences between these clades and the morphological differences support their representing distinct species so that Gelidium nayaritense sp. nov. is proposed for tropical specimens of the Mexican Pacific, whose diagnostic characteristics are the little or absent branching, its small size, as well as the presence of internal rhizoidal filaments concentrated in the subcortex, further G. sanyaense is register for first time from Mexico and Eastern Pacific.

Gelidium gonzalezii sp. nov. (Gelidiales, Rhodophyta) from the Mexican tropical Pacific based on molecular and morphological evidence

Phytotaxa ◽  
2020 ◽  
Vol 459 (2) ◽  
pp. 124-138
Author(s):  
NATALY QUIROZ-GONZÁLEZ ◽  
MA. EDITH PONCE-MÁRQUEZ ◽  
CINDY FERNÁNDEZ-GARCÍA ◽  
DENÍ RODRÍGUEZ
Keyword(s):  
Gulf Of California ◽  
Phylogenetic Analyses ◽  
Distinct Species ◽  
Tropical Pacific ◽  
Central American ◽  
Morphological Evidence ◽  
Tropical Region ◽  
Mexican Pacific ◽  
Pattern Shape ◽  
Morphological Differences

There are currently 23 reported species of Gelidium in Mexican Pacific coastal waters. Many of these species require taxonomic verification. Gelidium sclerophyllum is a species reported from the northern Gulf of California to the tropical region of the Mexican Pacific, but there is large morphological variation among populations. The objective of this research was to evaluate this species using a morphological and molecular approach, with COI-5P and rbcL molecular markers. A total of 13 samples were collected from five sites in the Mexican Tropical Pacific. Phylogenetic analyses resolved these specimens within a separate clade from that which includes the type of G. sclerophyllum and other Central American specimens. Differences with other species are subtle and based mainly on size, branching pattern, shape of tetrasporangia sori and size of tetraspores. The sequence divergences and the subtle morphological differences between these two clades support their recognition as two distinct species, and Gelidium gonzalezii sp. nov. is proposed for specimens from the Mexican Tropical Pacific.

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.

Integrative taxonomic investigation of Petaurus breviceps (Marsupialia: Petauridae) reveals three distinct species

2020 ◽  
Author(s):  
Teigan Cremona ◽  
Andrew M Baker ◽  
Steven J B Cooper ◽  
Rebecca Montague-Drake ◽  
Alyson M Stobo-Wilson ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Taxonomic Diversity ◽  
Distinct Species ◽  
Morphological Evidence ◽  
Northern Australia ◽  
Conservation Implications ◽  
Sugar Glider ◽  
Taxonomic Approach ◽  
Morphological Differences ◽  
Petaurus Breviceps

Abstract The Australian sugar glider, Petaurus breviceps s.l., is widely distributed across eastern and northern Australia. Examination of historical and contemporary collections of Petaurus specimens and phylogenetic analyses have revealed considerable taxonomic diversity within the genus. We aimed to utilize an integrative taxonomic approach, combining genetic and morphological evidence, to resolve the taxonomy of Australian gliders currently recognized as Petaurus breviceps. Herein, we confirm the existence of three distinct species: P. breviceps, P. notatus comb. nov. and P. ariel comb. nov.. Petaurus breviceps and P. notatus are each represented by major mtDNA lineages in P. breviceps, while P. ariel forms a sister-lineage to P. norfolcensis and P. gracilis. Subtle morphological differences distinguish P. breviceps from the closely related P. notatus, while the morphological distinctions between P. ariel and its genetically similar sister-taxa, P. norfolcensis and P. gracilis, are more obvious. Given the purported broad geographic distribution of the taxon, P. breviceps s.l. was not listed as threatened, but dividing this taxon into three species has important conservation implications for all taxa in the group, particularly given the lamentable record for mammal extinctions in Australia. Concerted and targeted conservation efforts are necessary to preserve these distinct, newly described species.

scholarly journals Two Novel Fungal Symbionts Fusarium kuroshium sp. nov. and Graphium kuroshium sp. nov. of Kuroshio Shot Hole Borer (Euwallacea sp. nr. fornicatus) Cause Fusarium Dieback on Woody Host Species in California

Plant Disease ◽  
2018 ◽  
Vol 102 (6) ◽  
pp. 1154-1164 ◽  
Author(s):  
Francis Na ◽  
Joseph D. Carrillo ◽  
Joey S. Mayorquin ◽  
Cedric Ndinga-Muniania ◽  
Jason E. Stajich ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Tree Species ◽  
Tree Mortality ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
San Diego County ◽  
Internal Transcribed Spacer Region ◽  
Branch Dieback ◽  
Fusarium Dieback ◽  
Disease Complexes

Shot hole borer (SHB)-Fusarium dieback (FD) is a new pest-disease complex affecting numerous tree species in California and is vectored by two distinct, but related ambrosia beetles (Euwallacea sp. nr. fornicatus) called polyphagous shot hole borer (PSHB) and Kuroshio shot hole borer (KSHB). These pest-disease complexes cause branch dieback and tree mortality on numerous wildland and landscape tree species, as well as agricultural tree species, primarily avocado. The recent discovery of KSHB in California initiated an investigation of fungal symbionts associated with the KSHB vector. Ten isolates of Fusarium sp. and Graphium sp., respectively, were recovered from the mycangia of adult KSHB females captured in three different locations within San Diego County and compared with the known symbiotic fungi of PSHB. Multigene phylogenetic analyses of the internal transcribed spacer region (ITS), translation elongation factor-1 alpha (TEF1-α), and RNA polymerase II subunit (RPB1, RPB2) regions as well as morphological comparisons revealed that two novel fungal associates Fusarium kuroshium sp. nov. and Graphium kuroshium sp. nov. obtained from KSHB were related to, but distinct from the fungal symbionts F. euwallaceae and G. euwallaceae associated with PSHB in California. Pathogenicity tests on healthy, young avocado plants revealed F. kuroshium and G. kuroshium to be pathogenic. Lesion lengths from inoculation of F. kuroshium were found to be significantly shorter compared with those caused by F. euwallaceae, while no difference in symptom severity was detected between Graphium spp. associated with KSHB and PSHB. These findings highlight the pest disease complexes of KSHB-FD and PSHB-FD as distinct, but collective threats adversely impacting woody hosts throughout California.

Electrophoretic and morphometric analyses of two sibling species pairs in Trachyphloeus (Coleoptera: Curculionidae)

1991 ◽  
Vol 22 (2) ◽  
pp. 159-170
Author(s):  
V. Simonsen ◽  
V. Loeschcke ◽  
V. Mahler ◽  
L.S. Jermn
Keyword(s):  
Sibling Species ◽  
Species Concept ◽  
Taxonomic Status ◽  
Distinct Species ◽  
Reliable Identification ◽  
Lack Of Information ◽  
Morphometric Analyses ◽  
Species Pairs ◽  
Parthenogenetic Reproduction ◽  
Morphological Differences

AbstractMisidentified specimens of Trachyphloeus bifoveolatus (Beck, 1817), T. angustisetulus Hansen, 1915, T. spinimanus Germar, 1824 and T. digitalis (Gyllenhal, 1827) are very frequent in weevil collections and reflect the ambiguous taxonomic status of some of these taxa. The taxonomic problems are a result of (1) sole use of traditional morphological differences, (2) the weevils' assumed parthenogenetic reproduction which prevents the use of Mayr's species concept, and (3) lack of information about their biology and genetics. Our present electrophoretic, morphometric and morphological analyses of live and dry-mounted samples of females from north and west Europe indicate that the four taxa are each genetically and morphologically distinct species. New keys which permit easy and reliable identification of the species are provided.

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.

scholarly journals Olive Twig and Branch Dieback in California Caused by Cytospora oleicola and the Newly Described Species Cytospora olivarum sp. nov.

Plant Disease ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 1908-1917 ◽  
Author(s):  
José Ramón Úrbez-Torres ◽  
Daniel P. Lawrence ◽  
Francesca Peduto Hand ◽  
Florent P. Trouillas
Keyword(s):  
Current Knowledge ◽  
Control Strategies ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Effective Control ◽  
Internal Transcribed Spacer Region ◽  
5.8S Rdna ◽  
Olive Trees ◽  
Branch Dieback ◽  
Taxonomic Studies

Field surveys conducted throughout California olive-growing regions in 2008 and 2009 resulted in a collection of 101 Cytospora-like isolates from olive twig and branch dieback symptoms. Cytospora isolates were isolated from multiple cvs. in different olive orchards in Fresno, Madera, Merced, Napa, Riverside, Santa Barbara, Sonoma, Tulare, and Ventura counties. Taxonomic studies of macro- and microscopic structures along with multigene phylogenetic analyses of the internal transcribed spacer region, including the 5.8S rDNA (ITS1–5.8S–ITS2), and fragments of the translation elongation factor 1-α, beta-tubulin, and actin genes identified two species, Cytospora oleicola and C. olivarum sp. nov. Pathogenicity studies conducted in mature olive trees cvs. Manzanillo and Sevillano showed both species to be pathogenic and able to cause vascular necrosis and cankers in olive branches. This study adds to the current knowledge on the etiology of olive twig and branch dieback and provides new important information for the development of effective control strategies against canker diseases affecting olive in California.

A scanning electron microscopic study of the eggs of Culicoides variipennis (Diptera: Ceratopogonidae)

1987 ◽  
Vol 45 ◽  
pp. 884-885 ◽  
Author(s):  
R. A. Nunamaker ◽  
C. E. Nunamaker ◽  
B. C. Wick
Keyword(s):  
Distinct Species ◽  
Hemorrhagic Disease ◽  
Insect Vector ◽  
Electron Microscopic ◽  
Important Species ◽  
Scanning Electron Microscopic Study ◽  
Laboratory Colony ◽  
Culicoides Variipennis ◽  
Morphological Differences ◽  
Scanning Electron

Culicoides variipennis (Coquillett) is probably the most economically important species of biting midge in the U.S. due to its involvement in the transmission of bluetongue (BT) disease of sheep, cattle and ruminant wildlife, and epizootic hemorrhagic disease (EHD) of deer. Proposals have been made to recognize the eastern and western populations of this insect vector as distinct species. Others recommend use of the term “variipennis complex” until such time that the necessary biosystematic studies have been made to determine the genetic nature and/or minute morphological differences within the population structure over the entire geographic range of the species. Increasingly, students of ootaxonomy are relying on scanning electron microscopy (SEM) to assess chorionic features. This study was undertaken to provide comparative chorionic data for the C. variipennis complex.Culicoides variipennis eggs were collected from a laboratory colony maintained in Laramie, Wyoming.

Sign in / Sign up

Export Citation Format

Share Document