Molecular identification, phylogeny and phylogeography of the entomopathogenic nematodes of the genus Heterorhabditis Poinar, 1976: a multigene approach

Summary Presently, the genus Heterorhabditis contains 16 valid entomopathogenic nematode species. In this study we used samples from 11 species: H. amazonensis, H. bacteriophora, H. baujardi, H. beicherriana, H. downesi, H. floridensis, H. georgiana, H. indica, H. megidis, H. noenieputensis, and H. zealandica to amplify and sequence five gene fragments: the D2-D3 expansion segments of 28S rRNA, ITS rRNA, COI mtDNA genes and unc-87 and cmd-1 genes encoding thin filament (F-actin)-associated protein and calmodulin, respectively. Fifty new sequences for 11 species were generated. More than 980 sequences of five genes were analysed. Phylogenetic and sequence analysis of these genes using Bayesian inference, maximum likelihood and statistical parsimony confirmed a division of the genus into three clades (groups): ‘Indica’, ‘Bacteriophora’ and ‘Megidis’. The analysis of gene sequences downloaded from GenBank and identified as Heterorhabditis revealed many cases of species misidentifications and presence of reading mistakes in some sequences. Synonymisation of H. somsookae with H. baujardi, H. gerrardi, H. pakistanensis with H. indica, and H. sonorensis with H. taysearae, are confirmed by sequence and phylogenetic analysis. The ITS rRNA and COI genes could be considered as informative markers for species identification, barcoding and phylogeographical studies of Heterorhabditis.

Download Full-text

Virulence of two entomopathogenic nematode species, Steinernema sp. (strain PQ16) and Heterorhabditis indica (strain KT3987), to nymphs of the coffee cicada Dundubia nagarasingna

Nematology ◽

10.1163/15685411-00003193 ◽

2019 ◽

Vol 21 (1) ◽

pp. 35-44 ◽

Cited By ~ 1

Author(s):

Chau N. Nguyen ◽

Anh T. Do ◽

Phap Q. Trinh ◽

Phuc K. Hoang

Keyword(s):

Biological Control ◽

Entomopathogenic Nematodes ◽

Entomopathogenic Nematode ◽

Nematode Species ◽

Mortality Rates ◽

Coffee Plantations ◽

Heterorhabditis Indica ◽

Inoculation Dose ◽

Pot Trial

Summary The virulence and efficacy of two species of entomopathogenic nematodes, Steinernema sp. (strain PQ16) and Heterorhabditis indica (strain KT3987), against nymphs of the coffee cicada, Dundubia nagarasingna, was evaluated under laboratory and glasshouse conditions. The highest mortality rates of coffee cicada nymphs caused by these two nematode strains were 93.5 and 100%, respectively, at an inoculation dose of 600 infective juveniles (IJ) nymph−1. The virulence (LC50) was established as 137.5 IJ and 149.1 IJ for strains S-PQ16 and H-KT3987, respectively. The highest IJ yields of these nematode strains were 66 × 103 IJ (for S-PQ16) and 134.4 × 103 IJ (for H-KT3987) at a dose of 500 IJ nymph−1. The efficacies of the two nematode strains to coffee cicadas at treated dose of 60 × 103 IJ pot−1 were 84.4 and 88.9% after 30 days, higher than the efficacies at treated dose of 40 × 103 IJ pot−1. The number of IJ in 250 ml of soil at 10, 20 and 30 days after treatment, increased from 0.38 × 103 to 4.80 × 103 IJ in soil treated with a dose of 40 × 103 IJ and from 0.66 × 103 to 5.02 × 103 IJ in soil treated with a dose of 60 × 103 IJ (for S-PQ16). Similarly, for H-KT3987 the number of IJ increased from 0.43 × 103 to 8.99 × 103 IJ and from 0.62 × 103 to 9.64 × 103 IJ, at the respective doses. Based on results of a pot trial from glasshouse modelling, an IJ application dosage for biological control of coffee cicada nymphs in coffee plantations was proposed.

Download Full-text

Entomopathogenic nematode (Heterorhabditidae and Steinernematidae) spatial distribution in turfgrass

Parasitology ◽

10.1017/s0031182000081543 ◽

1996 ◽

Vol 113 (5) ◽

pp. 473-482 ◽

Cited By ~ 50

Author(s):

J. F. Campbell ◽

E. Lewis ◽

F. Yoder ◽

R. Gaugler

Keyword(s):

Spatial Distribution ◽

Vertical Distribution ◽

Entomopathogenic Nematodes ◽

Entomopathogenic Nematode ◽

Soil Surface ◽

Nematode Species ◽

Horizontal Distribution ◽

Steinernema Carpocapsae ◽

Foraging Strategies ◽

Temporal And Spatial Distribution

SUMMARYUnderstanding the temporal and spatial distribution of entomopathogenic nematodes is essential for determining the role of these insect parasites in soil communities and ultimately for their use in suppression of pest insect populations. We measured the vertical and horizontal distribution of endemic populations of entomopathogenic nematodes (Steinernema carpocapsae and Heterorhabditis bacteriophord) in turfgrass. Vertical distribution was determined by taking soil cores every 3 h from 05.00 to 23.00 h, over 4 days, and dividing the cores into 8, 1 cm deep sections. Steinernema carpocapsae was recovered primarily near the soil surface: 50% of positive sections were recovered in the thatch or first 1 cm of soil. S. carpocapsae recovery was lower during the middle of the day and none were recovered in the upper section. H. bacteriophora was recovered uniformly throughout the top 8 cm of soil and its vertical distribution did not change over the course of the day. Horizontal distribution was measured as the number of nematodes recovered from cores taken from 12 randomly selected 0·3 × 0·8 m sections from within four 15·3 × 15·3 m plots. Samples were collected biweekly over a 9-month period. H. bacteriophora had a patchier distribution than S. carpocapsae and both nematode species had more patchy distributions then their potential hosts. Our results support the hypothesis that these two species of nematode utilize different foraging strategies; S. carpocapsae primarily a surface adapted ambusher and H. bacteriophora as a cruise forager.

Download Full-text

Efficacy of Two Entomopathogenic Nematode Species as Potential Biocontrol Agents against the Diamondback Moth, Plutella xylostella (L.)

Journal of Biological Control ◽

10.18311/jbc/30/2/14919 ◽

2016 ◽

Vol 30 (2) ◽

pp. 78

Author(s):

Masaaod Zolfagharian ◽

Ayatollah Saeedizadeh ◽

Habib Abbasipour

Keyword(s):

Plutella Xylostella ◽

Laboratory Experiments ◽

Entomopathogenic Nematodes ◽

Entomopathogenic Nematode ◽

Larval Mortality ◽

Diamondback Moth ◽

Nematode Species ◽

Steinernema Carpocapsae ◽

Important Pest ◽

High Larval Mortality

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae) is an important pest of cruciferous crops in Iran. The susceptibility of P. xylostella larvae to two species of entomopathogenic nematodes (EPNs) (Steinernema carpocapsae and Heterorhabditis bacteriophora) was examined under laboratory conditions. Leaf bioassays were conducted to evaluate the nematode's capability to reach the larvae and kill them. High larval mortality (72.6-96%) was observed in laboratory experiments. The ET50 of H. bacteriophora was higher than that of S. carpocapsae. The ET50 of entomopatpgenic nematodes, H. bacteriophora and S. carpocapsae tested ranged from 21 to 139.7 and 11.3 to 71.4 hours, respectively. The effect of both factors infective juveniles (IJs) and exposure time of 50% (ET50) on the larval mortality was significant (df = 6; P < 0.001) and (df = 2; P < 0.001), respectively. This study revealed that entomopatogenic nematodes (EPNs) have great potential that should be exploited in diamondback moth, P. xylostella management.

Download Full-text

Entomopathogenic nematodes: A tool in biocontrol of insect pests of vegetables-A review

Agricultural Reviews ◽

10.18805/ag.v38i02.7945 ◽

2017 ◽

Vol 38 (02) ◽

Cited By ~ 3

Author(s):

Gitanjali Devi ◽

Dhrubajyoti Nath

Keyword(s):

Biological Control ◽

Entomopathogenic Nematodes ◽

Insect Pests ◽

Entomopathogenic Nematode ◽

Insect Pest ◽

Nematode Species ◽

Vegetable Crops ◽

Biological Control Agents ◽

Isolation And Identification ◽

Identification Technique

Biological control agents have become increasingly important component in integrated pest management programme. Entomopathogenic nematodes are effective biological control agents for many important insect pests of vegetable crops. Therefore entomopathogenic nematodes are gaining attention in the field of biocontrol research worldwide. With the development and improvement of isolation and identification technique many novel species and strains have been utilized for management of several insect pests. This review aims to explore the potentiality of entomopathogenic nematode species against economically important insect pest of vegetables in India as well as in other countries.

Download Full-text

Molecular Characterisation and Phylogenetic Analysis of Dermatophytic Fungi Isolated from Tinea Capitis in Northwest Nigeria Using Sequence of the 28S rRNA

Microbiology Research ◽

10.3390/microbiolres12030046 ◽

2021 ◽

Vol 12 (3) ◽

pp. 646-655

Author(s):

Hussain Yahaya Ungo-kore ◽

Joseph Olorunmola Ehinmidu ◽

Josiah Ademola Onaolapo ◽

Olayeni Stephen Olonitola

Keyword(s):

Phylogenetic Analysis ◽

Tinea Capitis ◽

28S Rdna ◽

Clinical Samples ◽

28S Rrna ◽

Trichophyton Tonsurans ◽

Detection And Identification ◽

Microsporum Audouinii ◽

Trichophyton Simii ◽

Dermatophyte Species

The detection and identification of fungal DNA from clinical samples is one of the fundamental approaches in biomedicine. The incidence, distribution, and control of dermatophytes has progress significantly and the use of phylogenetic species concepts based on rRNA regions have enhanced the taxonomy of dermatophyte species; however, the use of 28S rDNA genes has certain limitations. This gene has been used in dermatophyte taxonomy with limited enumeration; we appraised the sequence disparity within and among groups of the species, the gene ranking in identification, phylogenetic analysis, and taxonomy of 32 strains of eight dermatophyte species. In this study, a set of primers was adopted to amplify the target followed by a partial sequencing of the rDNA. The utilization of a pairwise nucleotide differentiation, an affinity was observed among eight dermatophyte species, with disparity among species ranging from 0 to 197 base pair (bp). Intra-species bp differences were found within strains of Trichophyton eriotrephon, Trichophyton bullosum, Trichophyton simii (Trichophyton genus), Microsporum audouinii, and Trichophyton tonsurans (Microsporum and Trichophyton genus, respectively); however, only some strains of Trichophyton eriotrephon were found to be invariant having three genotypes. Trichophyton tonsurans exhibited most intra-species variability. The characterization and construction of a phylogenetic tree of 28S rDNA gene on dermatophyte species provide a bedrock of an additional finding of connections between species. However, 28S rRNA capture provides a novel method of effective and sensitive detection of dermatophytes lodged in human skin scale. We report for the first time the emergence of T. eriotrephon, T. bullosum, T. simii, T. benhamiae, and Ctenomyces serratus dermatophytes from Tinea capitis in Nigeria.

Download Full-text

Extensive Phylogenetic Analysis of Piscine Orthoreovirus Genomic Sequences Shows the Robustness of Subgenotype Classification

Pathogens ◽

10.3390/pathogens10010041 ◽

2021 ◽

Vol 10 (1) ◽

pp. 41

Author(s):

Marcos Godoy ◽

Daniel A. Medina ◽

Rudy Suarez ◽

Sandro Valenzuela ◽

Jaime Romero ◽

...

Keyword(s):

Phylogenetic Analysis ◽

Genetic Variation ◽

Sequence Analysis ◽

Molecular Phylogeny ◽

Phylogenetic Trees ◽

Genomic Segment ◽

Double Stranded Rna ◽

The Family ◽

Original Classification

Piscine orthoreovirus (PRV) belongs to the family Reoviridae and has been described mainly in association with salmonid infections. The genome of PRV consists of about 23,600 bp, with 10 segments of double-stranded RNA, classified as small (S1 to S4), medium (M1, M2 and M3) and large (L1, L2 and L3); these range approximately from 1000 bp (segment S4) to 4000 bp (segment L1). How the genetic variation among PRV strains affects the virulence for salmonids is still poorly understood. The aim of this study was to describe the molecular phylogeny of PRV based on an extensive sequence analysis of the S1 and M2 segments of PRV available in the GenBank database to date (May 2020). The analysis was extended to include new PRV sequences for S1 and M2 segments. In addition, subgenotype classifications were assigned to previously published unclassified sequences. It was concluded that the phylogenetic trees are consistent with the original classification using the PRV genomic segment S1, which differentiates PRV into two major genotypes, I and II, and each of these into two subgenotypes, designated as Ia and Ib, and IIa and IIb, respectively. Moreover, some clusters of country- and host-specific PRV subgenotypes were observed in the subset of sequences used. This work strengthens the subgenotype classification of PRV based on the S1 segment and can be used to enhance research on the virulence of PRV.

Download Full-text

Cloning, sequence analysis, and expression of the genes encoding the two subunits of the methylotrophic bacterium W3A1 electron transfer flavoprotein.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)31609-0 ◽

1994 ◽

Vol 269 (51) ◽

pp. 32120-32130

Author(s):

D Chen ◽

R P Swenson

Keyword(s):

Electron Transfer ◽

Sequence Analysis ◽

Methylotrophic Bacterium ◽

Electron Transfer Flavoprotein ◽

Genes Encoding

Download Full-text

A Family of Genes Clustered at the Triplo-lethal Locus of Drosophila melanogaster Has an Unusual Evolutionary History and Significant Synteny With Anopheles gambiae

Genetics ◽

10.1093/genetics/165.2.613 ◽

2003 ◽

Vol 165 (2) ◽

pp. 613-621 ◽

Cited By ~ 2

Author(s):

Douglas R Dorer ◽

Jamie A Rudnick ◽

Etsuko N Moriyama ◽

Alan C Christensen

Keyword(s):

Phylogenetic Analysis ◽

Drosophila Melanogaster ◽

Anopheles Gambiae ◽

Evolutionary History ◽

Codon Bias ◽

Good Target ◽

The Family ◽

Genes Encoding ◽

And Function ◽

Gambiae Genome

Abstract Within the unique Triplo-lethal region (Tpl) of the Drosophila melanogaster genome we have found a cluster of 20 genes encoding a novel family of proteins. This family is also present in the Anopheles gambiae genome and displays remarkable synteny and sequence conservation with the Drosophila cluster. The family is also present in the sequenced genome of D. pseudoobscura, and homologs have been found in Aedes aegypti mosquitoes and in four other insect orders, but it is not present in the sequenced genome of any noninsect species. Phylogenetic analysis suggests that the cluster evolved prior to the divergence of Drosophila and Anopheles (250 MYA) and has been highly conserved since. The ratio of synonymous to nonsynonymous substitutions and the high codon bias suggest that there has been selection on this family both for expression level and function. We hypothesize that this gene family is Tpl, name it the Osiris family, and consider possible functions. We also predict that this family of proteins, due to the unique dosage sensitivity and the lack of homologs in noninsect species, would be a good target for genetic engineering or novel insecticides.

Download Full-text

Description of a new species of Auriculostoma (Digenea: Allocreadiidae) from Characidium heirmostigmata (Characiformes: Crenuchidae) from Argentina, using morphological and molecular data

Journal of Helminthology ◽

10.1017/s0022149x21000109 ◽

2021 ◽

Vol 95 ◽

Author(s):

M.M. Montes ◽

J. Barneche ◽

Y. Croci ◽

D. Balcazar ◽

A. Almirón ◽

...

Keyword(s):

Phylogenetic Analysis ◽

New Species ◽

National Park ◽

Molecular Data ◽

Rrna Gene ◽

28S Rrna ◽

The Family ◽

Parasitological Survey ◽

Morphological And Molecular Data ◽

A New Species

Abstract During a parasitological survey of fishes at Iguazu National Park, Argentina, specimens belonging to the allocreadiid genus Auriculostoma were collected from the intestine of Characidium heirmostigmata. The erection of the new species is based on a unique combination of morphological traits as well as on phylogenetic analysis. Auriculostoma guacurarii n. sp. resembles four congeneric species – Auriculostoma diagonale, Auriculostoma platense, Auriculostoma tica and Auriculostoma totonacapanensis – in having smooth and oblique testes, but can be distinguished by a combination of several morphological features, hosts association and geographic distribution. Morphologically, the new species can be distinguished from both A. diagonale and A. platense by the egg size (bigger in the first and smaller in the last); from A. tica by a shorter body length, the genital pore position and the extension of the caeca; and from A. totonacapanensis by the size of the oral and ventral sucker and the post-testicular space. Additionally, one specimen of Auriculostoma cf. stenopteri from the characid Charax stenopterus (Characiformes) from La Plata River, Argentina, was sampled and the partial 28S rRNA gene was sequenced. The phylogenetic analysis revealed that A. guacurarii n. sp. clustered with A. tica and these two as sister taxa to A. cf. stenopteri. The new species described herein is the tenth species in the genus and the first one parasitizing a member of the family Crenuchidae.

Download Full-text