Pathogenicity of Photorhabdus Luminescens , a Symbiotic Bacterium of an Entomopathogenic Nematode against Galleria Mellonella L. and Spodoptera Littoralis ( Boise. )

2015 ◽  
Vol 63 ◽  
pp. 91-97 ◽  
Author(s):  
G. M. Nouh ◽  
M. A. Hussein
2013 ◽  
Vol 63 (Pt_5) ◽  
pp. 1853-1858 ◽  
Author(s):  
Tiarin Ferreira ◽  
Carol van Reenen ◽  
Sylvie Pagès ◽  
Patrick Tailliez ◽  
Antoinette P. Malan ◽  
...  

The bacterial symbiont AM7T, isolated from a novel entomopathogenic nematode species of the genus Heterorhabditis, displays the main phenotypic traits of the genus Photorhabdus and is highly pathogenic to Galleria mellonella. Phylogenetic analysis based on a multigene approach (16S rRNA, recA, gyrB, dnaN, gltX and infB) confirmed the classification of isolate AM7T within the species Photorhabdus luminescens and revealed its close relatedness to Photorhabdus luminescens subsp. caribbeanensis , P. luminescens subsp. akhurstii and P. luminescens subsp. hainanensis . The five concatenated protein-encoding sequences (4197 nt) of strain AM7T revealed 95.8, 95.4 and 94.9 % nucleotide identity to sequences of P. luminescens subsp. caribbeanensis HG29T, P. luminescens subsp. akhurstii FRG04T and P. luminescens subsp. hainanensis C8404T, respectively. These identity values are less than the threshold of 97 % proposed for classification within one of the existing subspecies of P. luminescens . Unlike other strains described for P. luminescens , strain AM7T produces acid from adonitol, sorbitol and xylitol, assimilates xylitol and has no lipase activity on medium containing Tween 20 or 60. Strain AM7T is differentiated from P. luminescens subsp. caribbeanensis by the assimilation of N-acetylglucosamine and the absence of haemolytic activity. Unlike P. luminescens subsp. akhurstii , strain AM7T does not assimilate mannitol, and it is distinguished from P. luminescens subsp. hainanensis by the assimilation of trehalose and citrate, the inability to produce indole from tryptophan and the presence of acetoin production and urease activity. Strain AM7T ( = ATCC BAA-2407T  = DSM 25462T) belongs to a novel subspecies, and is proposed as the type strain of Photorhabdus luminescens subsp. noenieputensis sp. nov.


Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 144 ◽  
Author(s):  
Esengül Özdemir ◽  
Şerife Bayram ◽  
İ. Alper Susurluk

The entomopathogenic nematode Steinernema litorale was isolated from Çamkoru Nature Park located in Ankara, Turkey, in September 2018. Steinernema litorale was recovered in 1 of 67 soil samples from a natural forest area; the soil was characterised as sandy loam. The isolated nematode S. litorale was identified based on morphological and molecular parameters. The symbiotic bacterium of S. litorale was determined as Xenorhabdus bovienii. Steinernema litorale was found for the first time in Turkey and the Middle East. The virulence of the isolate was tested on Galleria mellonella larvae. Different concentrations of the nematode (10, 25, 50, 75, and 100 infective juveniles (IJs/larvae) were used. While the LC50 values at 48 h, 72 h, and 96 h were 153.419, 51.005, and 15.439 IJs, respectively, and the LT50 values at 75 IJs and 100 IJs showed that this isolate is capable to control insect larvae within 50.083 and 36.266 h, respectively.


2018 ◽  
Author(s):  
Fernando L. Kamitani ◽  
Daniela P. Almenara ◽  
Carolina Rossi ◽  
Maira R. Camargo Neves ◽  
Lissandra M. A. Müller ◽  
...  

AbstractMany isolates of the genus Photorhabdus have been reported around the world. Here we describe the first Brazilian Photorhabdus isolate, found in association with the entomopathogenic nematode Heterorhabditis baujardi LPP7, from the Amazonian forest in Monte Negro (RO, Brazil). The new isolate can be grouped with the Hb-Hm clade of P. luminescens subsp. luminescens, close to the new subspecies P. luminescens subsp. sonorensis. P. luminescens MN7 has several characteristics expected of variant form I cells, such as the presence of intracellular crystals, secretion of hydrolytic enzymes (lipases and proteases) and bioluminescence. Although H. baujardi LPP7 is not prolific when compared to H. bacteriophora HP88, P. luminescens MN7 is clearly pathogenic and probably secretes the same toxins as P. luminescens subsp. luminescens W14, when fed to larvae of the greater wax moth Galleria mellonella. This behavior is different from what is found in Photorhabdus luminescens subsp. laumondii HP88, which was used as a control in our experiments, and P. l. subsp. laumondii TT01. Besides the toxin secretion, P. luminescens MN7 secretes proteolytic polypeptides that have molecular masses different from those found in P. l. subsp. laumondii TT01. Finally, the crude extract from spent culture medium was shown to contain 3,5-dihydroxy-4-isopropyl-cis-stilbene and 1,3,8-trihydroxy-9,10-anthraquinone as the major compounds, similarly to other Photorhabdus luminescens strains.


Parasitology ◽  
1997 ◽  
Vol 114 (5) ◽  
pp. 483-488 ◽  
Author(s):  
P. S. GREWAL ◽  
M. MATSUURA ◽  
V. CONVERSE

We suggest a new mechanism for the maintenance of specificity of the association between the entomopathogenic nematode Steinernema scapterisci and its symbiotic bacteria. We evaluated the development and reproduction of infective and non-infective juvenile S. scapterisci in monoxenic combinations with its symbiotic bacteria, Xenorhabdus sp. ‘S’ and with the bacterial symbiont of Steinernema carpocapsae and Steinernema riobravis. Although development of non-infective stages occurred on all Xenorhabdus spp., the development of infective juveniles to the 4th stage (‘dauer’ recovery) was significantly delayed and reduced with X. nematophilus and Xenorhabdus sp. ‘R’, the bacterial symbionts of S. carpocapsae and S. riobravis, respectively. ‘Dauer’ recovery improved significantly when the cultures of X. nematophilus and Xenorhabdus sp. ‘R’ were supplemented with cell-free filtrates from Xenorhabdus sp. ‘S’. The infective juvenile S. scapterisci produced in all 3 cultures were virulent to Galleria mellonella larvae, confirming successful retention of Xenorhabdus from other steinernematids in their intestine. In fact, S. scapterisci infective juveniles containing X. nematophilus or Xenorhabdus sp. ‘R’ were more virulent to G. mellonella than those containing their natural symbiont, Xenorhabdus sp. ‘S’. We believe that this is the first demonstration of the symbiont-specific exit of infective juveniles from the ‘dauer’ phase which represents the finest level of specificity of bacteria–nematode association. This is also the first report of successful isolation of the natural symbiont of S. scapterisci.


1998 ◽  
Vol 44 (11) ◽  
pp. 1072-1077 ◽  
Author(s):  
Kaiji Hu ◽  
Jianxiong Li ◽  
Wenjie Wang ◽  
Houming Wu ◽  
Hai Lin ◽  
...  

The types of metabolites produced by Photorhabdus luminescens C9 when it is introduced by Heterorhabditis megidis 90 into Galleria mellonella larvae are different from those produced in tryptic soy broth. Only 3,5-dihydroxy-4-isopropylstilbene 1 was identified from the organic extracts of P. luminescens culture broth, but both 3,5-dihydroxy-4-isopropylstilbene 1 and 3,5-dihydroxy-4-ethylstilbene 3 were isolated from the organic extracts of nematode-bacterium infected G. mellonella larvae. In addition to two pigments, both of which had been previously reported from P. luminescens C9 culture broth, three pigments, 1,8-dihydroxy-3-methoxy-9,10-anthraquinone 2, 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone 6, and 1,4-dihydroxy-2,5-dimethoxy-9,10-anthraquinone 7 were isolated from the organic extracts of G. mellonella larvae infected by the nematode-bacterium complex. Among these, compounds 6 and 7 are novel and isolated from a natural source for the first time.Key words: Photorhabdus luminescens, Heterorhabditis megidis, 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, 1,4-dihydroxy-2,5-dimethoxy-9,10-anthraquinone, pigment.


Nematology ◽  
2001 ◽  
Vol 3 (8) ◽  
pp. 849-853 ◽  
Author(s):  
Ralf-Udo Ehlers ◽  
Jens Aumann

AbstractRecovery in entomopathogenic nematodes is the exit from the dauer juvenile stage. It is a response to environmental queues signalling the presence of food sources (e.g., insect haemolymph). The bacterium Photorhabdus luminescens excretes a signal which also induces recovery of its symbiotic Heterorhabditis bacteriophora dauer juveniles. This bacterial signal is composed of at least two compounds with different polarity. The symbiotic bacteria also secrete an antagonistic signal which inhibits nematode recovery. The recovery-inducing signal compounds have a molecular mass of less than 20 kDa and are negatively charged. The data indicate that at least one compound is smaller than 5 kDa. The bacterial signal triggers by receptor binding, the first step in a recovery-inducing muscarinic signalling pathway.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Gehan Mohamed Nouh

Abstract Background Entomopathogenic nematodes (EPNs), as biological control agents, have been isolated from many regions throughout the world. Local isolates of EPNs are usually more effective for controlling indigenous insect pests as they are adapted to the local environmental conditions and the insect pest species. Results In the present work, EPN isolates were searched in the soil under citrus and guava trees, and Egyptian clover at Noubaria region, Elbhaira governorate, Egypt, within two consecutive years. The EPNs were isolated from two positive soil samples of Egyptian clover (Trifolium alexandrinum) (TAN5) and guava trees (Psidium guajava) (PGN6), while the EPNs were not existent in the soil samples under citrus. Laboratory applications of the two EPNs isolates against the cotton leafworm, Spodoptera littoralis(Boisd.), and the black cutworm, Agrotis ipsilon (Hufn.) (Lepidoptera: Noctuidae), were recorded. Nematodes naturally occurring in the soil were trapped by full-grown larvae of the greater wax moth (Galleria mellonella L.). Infected larvae turned from whitish beige to dark reddish color, proofed that these isolates belong to the genus Heterorhabditis. Laboratory results revealed that the mortality rate ranges from 24 to 100% with TAN5 while from 18 to 96% with PGN6 at A. ipsilon larvae. The LC50 values of TAN5 against A. ipsilon were 1285.527 and 1560.747 IJs/cup, while those values for S. littoralis were 1339.099 and 2531.605 IJs/cup in larvae and pupae, respectively. The 3rd instar larvae of A. ipsilon and S. littoralis were more sensitive than the pupae. Production of Heterorhabditis sp. strain TAN5 was the highest in the reproduction of infective juveniles than the strain PGN6 at all concentrations. Conclusions The EPNs isolated from the soil samples belonged to the genus Heterorhabditis. Heterorhabditis sp. strain (TAN5) collected from the soil under Egyptian clover at Noubaria region was the highest reproduction and the most effective against both tested pests, A. ipsilon and S. littoralis larvae and pupae. EPN species would serve as an alternative to chemical pesticides and fit well in an integrated pest management program against larvae as well as adults and pupae of many economic insect pests which inhabit the soil.


Parasitology ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 889-898 ◽  
Author(s):  
J. M. CHRISTEN ◽  
J. F. CAMPBELL ◽  
E. E. LEWIS ◽  
D. I. SHAPIRO-ILAN ◽  
S. B. RAMASWAMY

SUMMARYPotential hosts for infective juveniles of entomopathogenic nematodes can vary considerably in quality based on the characteristics of the host species/stage, physiological status (e.g. stress, feeding on toxins), and infection status (heterospecific or conspecific infection). In this study, we investigated responses of the entomopathogenic nematodeSteinernema riobraveto hosts (Galleria mellonellaorTenebrio molitor) that were previously parasitized with conspecifics or injected with the nematode-symbiotic bacterium,Xenorhabdussp., to determine if there is a preference for previously parasitized/injected hosts and when this preference might occur. In no-choice bioassays, the number of juveniles infecting both host species decreased with increasing time post-infection. However, infective juveniles continued to infect previously parasitized hosts up to 72 h. Significant preference was exhibited byS. riobravefor 24 h post-infectionG. mellonellalarvae over uninfected, and by 24 h post-injectionG.mellonellalarvae over 48 h post-injection larvae. No significant preference was exhibited byS. riobraveforT. molitorhosts previously parasitized with conspecifics or those injected with bacteria in any treatment combination. Such preference for, or continued infection of parasitized insects, has the potential to impact nematode efficacy.


Sign in / Sign up

Export Citation Format

Share Document