scholarly journals Morphometric and Molecular Diversity among Seven European Isolates of Pratylenchus penetrans

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 674
Author(s):  
Mesfin Bogale ◽  
Betre Tadesse ◽  
Rasha Haj Nuaima ◽  
Bernd Honermeier ◽  
Johannes Hallmann ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Management Strategies ◽  
Ornamental Plants ◽  
Geographic Origin ◽  
Tail Length ◽  
Nematode Species ◽  
Intraspecific Diversity ◽  
Effective Control ◽  
Pratylenchus Penetrans ◽  
The Usa

Pratylenchus penetrans is an economically important root-lesion nematode species that affects agronomic and ornamental plants. Understanding its diversity is of paramount importance to develop effective control and management strategies. This study aimed to characterize the morphological and genetic diversity among seven European isolates. An isolate from the USA was included in the molecular analyses for comparative purposes. Morphometrics of the European P. penetrans isolates generally were within the range of the original descriptions for this species. However, multiple morphometric characteristics, including body length, maximum body width, tail length and length of the post-vulval uterine sac showed discrepancies when compared to other populations. Nucleotide sequence-based analyses revealed a high level of intraspecific diversity among the isolates. We observed no correlation between D2-D3 rDNA- and COXI-based phylogenetic similarities and geographic origin. Our phylogenetic analyses including selected GenBank sequences also suggest that the controversy surrounding the distinction between P. penetrans and P. fallax remains.

Species composition and structure of complex of phytonematodes of ornamental plants under conditions of Kiev Goloseevskiy park

2018 ◽  
Vol 12 (2) ◽  
pp. 91-94
Author(s):  
A.A. Babich ◽  
A.G. Babich
Keyword(s):  
Species Composition ◽  
Ornamental Plants ◽  
Nematode Species ◽  
Taxonomic Structure ◽  
Pratylenchus Penetrans ◽  
Composition And Structure ◽  
Ornamental Crops ◽  
Ditylenchus Dipsaci ◽  
Longidorus Elongatus

The purpose of the research: study of fauna phytonematodes of ornamental crops. Materials and methods. Studies were conducted in 2016-2017 years in Kiev Goloseevskiy park, Ukraine. Materials for studies were samples of soil, plants, larvae and adult nematodes. Production of temporal and permanent preparations, determination of nematode species composition were conducted according to common methods. Results and discussion. 41 phytonematode species belonging to 29 species, 16 families and 5 series were found in rhizosphere of ornamental plants of Goloseevskiy park. According to taxonomic structure 49% species of ornamental plant phytonematode complex belong to Tylenchidae, 36% - to Rhabditida, 7% - to Dorylaimida, 4% - to Enoplida and 4% - to Araeolaimida. It is reasonable to divide species of nematodes found in rhizosphere of plants into 4 groups: phytohelminths, micohelminths, saprobionts and predaceous species. Phytohelminths are 11 species, micohelminths are 7 species, saprobionts are 20 species and 2 species are predaceous speciesof nematodes. Cassagnau index was used in order to determine the state of dominance of dispersed species of nematodes (Cassagnau, 1947). According to this parameter Helycotylenchus dihystera, Aphelenchoides fragarie and Ditylenchus dipsaci were the predominate phytoparasitic species. The following species which we often found were: Tylenchorhynchus dubius, Pratylenchus penetrans, P. pratensis, D. destructor, Paratylenchus nanus, Rotylenchus robustus, A. ritzemabosi, species which we found rarely was Longidorus elongatus.

scholarly journals Symptom Development in Response to Combined Infection of In Vitro-grown Lilium longiflorum with Pratylenchus penetrans and Soilborne Fungi Collected from Diseased Roots of Field-grown Lilies

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 882-889 ◽  
Author(s):  
Dilip Lakshman ◽  
Paulo Vieira ◽  
Ruchi Pandey ◽  
Janet Slovin ◽  
Kathryn Kamo
Keyword(s):  
Pacific Northwest ◽  
Phylogenetic Analyses ◽  
Lilium Longiflorum ◽  
Nematode Species ◽  
The United States ◽  
Pratylenchus Penetrans ◽  
First Report ◽  
Fungal Isolates ◽  
Easter Lily

Eight fungal isolates (ELRF 1 to 8) were recovered from necrotic roots of Easter lilies, Lilium longiflorum cv. Nellie White, grown in a field in the U.S. Pacific Northwest. The eight fungal isolates were identified by sequencing and molecular phylogenetic analyses based on their ITS rDNA region. Five isolates were identified as Fusarium oxysporum, two as F. tricinctum, and one as Rhizoctonia sp. AG-I. This constitutes the first report of Rhizoctonia sp. AG-I infecting lilies worldwide and the first report of F. tricinctum infecting lilies in the United States. To study and validate their pathogenicity, pure cultures of each isolate were used to infect the roots of Easter lily plants growing in vitro. In addition, Easter lily plants growing in vitro were infected either with or without Pratylenchus penetrans, the root lesion nematode, prior to placing a culture plug of fungus 1 cm from a lily root. Pratylenchus penetrans is a nematode species commonly found in the sampled fields. The presence of both nematode and Rhizoctonia sp. AG-I isolate ELRF 3 in infected lilies was evaluated by molecular analyses, confirming the infection of roots 3 days after inoculation, prior to development of disease symptoms. Necrosis and root rot developed more rapidly with all eight fungal isolates when there had been prior infection with P. penetrans, the major nematode parasitizing Easter lily roots in the field in Oregon.

scholarly journals Characterization of Phytophthora spp. Isolated from Ornamental Plants in Florida

Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 500-509 ◽  
Author(s):  
Jaimin S. Patel ◽  
Anne Vitoreli ◽  
Aaron J. Palmateer ◽  
Ashraf El-Sayed ◽  
David J. Norman ◽  
...  
Keyword(s):  
Mating Type ◽  
Phylogenetic Analyses ◽  
Management Strategies ◽  
Ornamental Plants ◽  
Phytophthora Nicotianae ◽  
Cross Resistance ◽  
Phytophthora Spp ◽  
Molecular Phylogenetic ◽  
Ornamental Crops

This report investigates population structure and genetic variability of Phytophthora spp. isolated from botanically diverse plants in Florida. Internal transcribed spacer-based molecular phylogenetic analyses indicate that Phytophthora isolates recovered from ornamental plants in Florida represent a genetically diverse population and that a majority of the isolates belong to Phytophthora nicotianae (73.2%), P. palmivora (18.7%), P. tropicalis (4.9%), P. katsurae (2.4%), and P. cinnamomi (0.8%). Mating type analyses revealed that most isolates were heterothallic, consisting of both mating type A1 (25.2%) and mating type A2 (39.0%), and suggesting that they could outcross. Fungicide sensitivity assays determined that several isolates were moderate to completely insensitive to mefenoxam. In addition, several isolates were also moderately insensitive to additional fungicides with different modes of action. However, correlation analyses did not reveal occurrence of fungicide cross-resistance. These studies suggest that a genetically diverse Phytophthora population infects ornamental crops and the occurrence of mefenoxam-insensitive Phytophthora populations raises concerns about disease management in ornamentals. Mitigating fungicide resistance will require prudent management strategies, including tank mixes and rotation of chemicals with different modes of actions.

scholarly journals On the Close Relatedness of Two Rice-Parasitic Root-Knot Nematode Species and the Recent Expansion of Meloidogyne graminicola in Southeast Asia

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 175 ◽  
Author(s):  
Guillaume Besnard ◽  
Ngan Thi-Phan ◽  
Hai Ho-Bich ◽  
Alexis Dereeper ◽  
Hieu Trang Nguyen ◽  
...  
Keyword(s):  
Genomic Structure ◽  
Phylogenetic Analyses ◽  
Nuclear Genome ◽  
Nematode Species ◽  
Intraspecific Diversity ◽  
Nuclear Ribosomal Dna ◽  
Genomic Sequences ◽  
Root Knot Nematode ◽  
Meloidogyne Graminicola ◽  
Close Phylogenetic Relationship

Meloidogyne graminicola is a facultative meiotic parthenogenetic root-knot nematode (RKN) that seriously threatens agriculture worldwide. We have little understanding of its origin, genomic structure, and intraspecific diversity. Such information would offer better knowledge of how this nematode successfully damages rice in many different environments. Previous studies on nuclear ribosomal DNA (nrDNA) suggested a close phylogenetic relationship between M. graminicola and Meloidogyne oryzae, despite their different modes of reproduction and geographical distribution. In order to clarify the evolutionary history of these two species and explore their molecular intraspecific diversity, we sequenced the genome of 12 M. graminicola isolates, representing populations of worldwide origins, and two South American isolates of M. oryzae. k-mer analysis of their nuclear genome and the detection of divergent homologous genomic sequences indicate that both species show a high proportion of heterozygous sites (ca. 1–2%), which had never been previously reported in facultative meiotic parthenogenetic RKNs. These analyses also point to a distinct ploidy level in each species, compatible with a diploid M. graminicola and a triploid M. oryzae. Phylogenetic analyses of mitochondrial genomes and three nuclear genomic sequences confirm close relationships between these two species, with M. graminicola being a putative parent of M. oryzae. In addition, comparative mitogenomics of those 12 M. graminicola isolates with a Chinese published isolate reveal only 15 polymorphisms that are phylogenetically non-informative. Eight mitotypes are distinguished, the most common one being shared by distant populations from Asia and America. This low intraspecific diversity, coupled with a lack of phylogeographic signal, suggests a recent worldwide expansion of M. graminicola.

scholarly journals Phylogenetic analysis of Tomato mosaic virus from Hemerocallis sp. and Impatiens hawkeri

2007 ◽  
Vol 33 (4) ◽  
pp. 409-413 ◽  
Author(s):  
Lígia Maria Lembo Duarte ◽  
Maria Amélia Vaz Alexandre ◽  
Eliana Borges Rivas ◽  
Marina Blanco Cattai ◽  
Rodrigo Martins Soares ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Phylogenetic Analyses ◽  
Rna Extraction ◽  
Ornamental Plants ◽  
Pcr Amplification ◽  
Tomato Mosaic Virus ◽  
The Usa ◽  
Impatiens Hawkeri ◽  
Geographical Locations ◽  
Ornamental Species

The culture and commercialization of ornamental plants have considerably increased in the last years. To supply the commercial demand, several Hemerocallis and Impatiens varieties have been bred for appreciated qualities such as flowers with a diversity of shapes and colors. With the aim of characterizing the tobamovirus isolated from Hemerocallis sp. (tobamo-H) and Impatiens hawkeri (tobamo-I) from the USA and São Paulo, respectively, as well as to establish phylogenetic relationships between them and other Tobamovirus species, the viruses were submitted to RNA extraction, RT-PCR amplification, coat-protein gene sequencing and phylogenetic analyses. Comparison of tobamovirus homologous sequences yielded values superior to 98.5% of identity with Tomato mosaic virus (ToMV) isolates at the nucleotide level. In relation to tobamo-H, 100% of identity with ToMV from tomatoes from Australia and Peru was found. Based on maximum likelihood (ML) analysis it was suggested that tobamo-H and tobamo-I share a common ancestor with ToMV, Tobacco mosaic virus, Odontoglossum ringspot virus and Pepper mild mottle virus. The tree topology reconstructed under ML methodology shows a monophyletic group, supported by 100% of bootstrap, consisting of various ToMV isolates from different hosts, including some ornamentals, from different geographical locations. The results indicate that Hemerocallis sp. and I. hawkeri are infected by ToMV. This is the first report of the occurrence of this virus in ornamental species in Brazil.

scholarly journals Identification, Virulence and Fungicide Sensitivity of Colletotrichum gloeosporioides s.s. Responsible for Walnut Anthracnose Disease in China

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1358-1368 ◽  
Author(s):  
Qing-Hai Wang ◽  
Kun Fan ◽  
De-Wei Li ◽  
Chuan-Ming Han ◽  
Yong-Yun Qu ◽  
...  
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Phylogenetic Analyses ◽  
Juglans Regia ◽  
Population Diversity ◽  
Intraspecific Diversity ◽  
Effective Control ◽  
Maximal Effect ◽  
Fungicide Sensitivity ◽  
Geographic Regions ◽  
Walnut Leaves

Walnut (Juglans regia L.) is an economically important woody nut and edible oil tree all over the world. However, walnut production is limited by walnut anthracnose, which is a disastrous disease that causes significant yield losses. Studying the etiology of anthracnose on walnut and the pathogens’ virulence and sensitivities to fungicides would be beneficial for effective control. This study was conducted to identify the pathogen of walnut anthracnose and reveal the population diversity of pathogens through virulence, sensitivities to fungicides, and genetic variation. A total of 13 single-spore Colletotrichum isolates were collected from walnut anthracnose-diseased fruits and leaves from 13 walnut commercial orchards in Henan, Hubei, Shandong, and Shaanxi provinces in China. The isolates were identified as Colletotrichum gloeosporioides sensu stricto (s.s.) according to multilocus phylogenetic analyses (internal transcribed spacer, actin, glyceraldehyde-3-phosphate dehydrogenase, and chitin synthase), morphological as well as cultural characters, and pathogenicity. When the same walnut tissue was inoculated with different isolates, the disease lesion size was different. The results showed that the virulence of all isolates was considerably different, and the differences were not correlated with geographic origins. The virulence to walnut leaves and fruits inoculated with the same isolate was significantly different. Based on the virulence to walnut leaves and fruits, the 13 isolates were divided into three groups. Virulence of 69.2% of the isolates to walnut fruits was higher than that to leaves; 15.4% of isolates had no difference in pathogenicity, and the virulence to walnut leaves was higher for 15.4% of isolates. Tebuconazole, difenoconazole, flusilazole, and carbendazim inhibited the growth of fungal mycelia, and the concentration for 50% of maximal effect (EC50) values were 0.4 to 20.5, 0.6 to 2.6, 0.2 to 1.6, and 0.002 to 0.2 µg/ml, respectively, with average values of 6.5 ± 6.9, 1.5 ± 0.6, 0.9 ± 0.4, and 0.1 ± 0.05 µg/ml, respectively. All isolates were more sensitive to difenoconazole, flusilazole, and carbendazim than tebuconazole (P < 0.01). Isolate sensitivities to the same fungicide were different. Isolates SL-31 and TS-09 were the least sensitive to carbendazim and tebuconazole, respectively, and the resistance ratios were 87.3 and 51.6, respectively. Sensitivities to difenoconazole and flusilazole were largely consistent among all isolates, and the resistance ratios were from 1 to 4.6 and from 1 to 7, respectively. Therefore, difenoconazole and flusilazole could be chosen for disease control. The differences of pathogenicity and fungicide sensitivity were not correlated with geographic regions. These results indicated that there was high intraspecific diversity of populations in C. gloeosporioides s.s. that caused walnut anthracnose. For effective management, the targeted control strategy should be implemented based on the different geographic regions.

IPM—A Problem-based Learning Approach

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 509e-509
Author(s):  
Robert P. Rice
Keyword(s):  
Pest Control ◽  
Test Performance ◽  
Management Strategies ◽  
Ornamental Plants ◽  
Real Life ◽  
Problem Based Learning ◽  
Control Measures ◽  
Learning Approach ◽  
Pest Monitoring ◽  
Use Of Resources

The Cal Poly philosophy of “Learn and Understand by Doing” has been integrated with problem-based learning and the use of the latest technology to produce a class that closely simulates real-life pest control situations. Goals of the class, Disease and Pest Control Systems for Ornamental Plants, are to teach students pest monitoring, control and problem solving techniques, the use of resources including the internet and journals, and the use of the latest pest control equipment and application techniques. Students are shown pest situations and then work in groups to diagnose the problem, investigate management strategies, apply control measures, and monitor results. Weekly class presentations inform the class of the various projects and help to teach the class organization and presentation skills. Student evaluations and test performance have demonstrated that students achieve class objectives substantially better with the problem-based learning approach than with the previous lecture-based approach to the class.

scholarly journals Multilocus phylogenies reveal three new truffle-like taxa and the traces of interspecific hybridization in Octaviania (Boletaceae, Boletales)

IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Takamichi Orihara ◽  
Rosanne Healy ◽  
Adriana Corrales ◽  
Matthew E. Smith
Keyword(s):  
Rna Polymerase Ii ◽  
Phylogenetic Analyses ◽  
Large Subunit ◽  
Gene Tree ◽  
Phylogenetic Network ◽  
Elongation Factor ◽  
Morphological Observation ◽  
Tree Comparison ◽  
Unknown Species ◽  
The Usa

ABSTRACTAmong many convergently evolved sequestrate fungal genera in Boletaceae (Boletales, Basidiomycota), the genus Octaviania is the most diverse. We recently collected many specimens of Octaviania subg. Octaviania, including several undescribed taxa, from Japan and the Americas. Here we describe two new species in subgenus Octaviania, O. tenuipes and O. tomentosa, from temperate to subtropical evergreen Fagaceae forests in Japan based on morphological observation and robust multilocus phylogenetic analyses (nrDNA ITS and partial large subunit [LSU], translation elongation factor 1-α gene [TEF1] and the largest subunit of RNA polymerase II gene [RPB1]). Based on specimens from the Americas as well as studies of the holotype, we also taxonomically re-evaluate O. asterosperma var. potteri. Our analysis suggests that O. asterosperma var. potteri is a distinct taxon within the subgenus Octaviania so we recognize this as O. potteri stat. nov. We unexpectedly collected O. potteri specimens from geographically widespread sites in the USA, Japan and Colombia. This is the first verified report of Octaviania from the South American continent. Our molecular analyses also revealed that the RPB1 sequence of one O. tenuipes specimen was identical to that of a closely related species, O. japonimontana, and that one O. potteri specimen from Minnesota had an RPB1 sequence of an unknown species of O. subg. Octaviania. Additionally, one O. japonimontana specimen had an unusually divergent TEF1 sequence. Gene-tree comparison and phylogenetic network analysis of the multilocus dataset suggest that these heterogenous sequences are most likely the result of previous inter- and intra-specific hybridization. We hypothesize that frequent hybridization events in Octaviania may have promoted the high genetic and species diversity found within the genus.

scholarly journals Uncovering two phases of early intercontinental COVID-19 transmission dynamics

2020 ◽  
Vol 27 (8) ◽  
Author(s):  
Jing Yang ◽  
Juan Li ◽  
Shengjie Lai ◽  
Corrine W Ruktanonchai ◽  
Weijia Xing ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
International Travel ◽  
Contact Tracing ◽  
Genetic Sequencing ◽  
Response Strategies ◽  
The World ◽  
Containment Measures ◽  
The Usa ◽  
Community Transmission ◽  
Two Phases

Abstract Background The COVID-19 pandemic has posed an ongoing global crisis, but how the virus spread across the world remains poorly understood. This is of vital importance for informing current and future pandemic response strategies. Methods We performed two independent analyses, travel network-based epidemiological modelling and Bayesian phylogeographic inference, to investigate the intercontinental spread of COVID-19. Results Both approaches revealed two distinct phases of COVID-19 spread by the end of March 2020. In the first phase, COVID-19 largely circulated in China during mid-to-late January 2020 and was interrupted by containment measures in China. In the second and predominant phase extending from late February to mid-March, unrestricted movements between countries outside of China facilitated intercontinental spread, with Europe as a major source. Phylogenetic analyses also revealed that the dominant strains circulating in the USA were introduced from Europe. However, stringent restrictions on international travel across the world since late March have substantially reduced intercontinental transmission. Conclusions Our analyses highlight that heterogeneities in international travel have shaped the spatiotemporal characteristics of the pandemic. Unrestricted travel caused a large number of COVID-19 exportations from Europe to other continents between late February and mid-March, which facilitated the COVID-19 pandemic. Targeted restrictions on international travel from countries with widespread community transmission, together with improved capacity in testing, genetic sequencing and contact tracing, can inform timely strategies for mitigating and containing ongoing and future waves of COVID-19 pandemic.

scholarly journals A Review of Alternative Management Tactics Employed for the Control of Various Cockroach Species (Order: Blattodea) in the USA

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 550
Author(s):  
Ameya D. Gondhalekar ◽  
Arthur G. Appel ◽  
Gretchen M. Thomas ◽  
Alvaro Romero
Keyword(s):  
Applied Research ◽  
Research Effort ◽  
Effective Control ◽  
Control Methods ◽  
Alternative Tactics ◽  
Alternative Control ◽  
The Public ◽  
Concurrent Use ◽  
The Usa ◽  
Alternative Control Methods

Effective control of domestic and peridomestic cockroaches requires integrated approaches that emphasize concurrent use of chemicals with alternative control tactics. An integrated pest management (IPM) approach is particularly justified in environments where satisfactory cockroach control cannot be achieved due to multiple factors including development of insecticide aversion and resistance in some cockroach species, and poor sanitation or structural issues that foster infestations. While a flurry of research effort has been devoted to study alternative tactics for cockroach control, only a few of them have been evaluated in the context of IPM programs. This review focuses on examining studies on alternative tactics that are proven efficacious, economical, and logistically feasible for their inclusion in IPM programs for important domestic and peridomestic cockroaches in the USA. Management programs that educate the public on cockroach biology, behavior, and the importance of sanitation; use of traps to monitor infestation levels; apply targeted low impact insecticides such as baits, have demonstrated a greater success for effective and sustainable control of cockroaches when compared to an insecticide-only approach. Incorporation of other alternative control methods to IPM programs will require more applied research that validates their use in real-world scenarios and demonstrates their cost-effectiveness.

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