Oral toxicity of Photorhabdus culture media on gene expression of the adult sweetpotato whitefly, Bemisia tabaci

Shrestha, Yam Kumar; Lee, Kyeong-Yeoll

doi:10.1016/j.jip.2011.10.011

Cited by 24 publications

(12 citation statements)

References 29 publications

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“…A single colony of each isolate of Photorhabdus and Xenorhabdus on NBTA was transferred, in sterile conditions, into a 15 ml tube containing 5 ml of 5YS broth medium which was composed of 5% yeast extract (w/v), 0.5% NaCl (w/v), 0.05% K 2 HPO 4 (w/v), 0.05% NH 2 H 2 PO 4 (w/v), 0.02% MgSO 4 .7H 2 O (w/v) [ 36 ]. The tubes were then incubated while shaking (150 rpm ) at room temperature for 48 h. Each tube of the bacterial suspension was then centrifuged at 10,000 rpm for 10 min to obtain a bacterial pellet which was then resuspended in sterile distilled water.…”

Section: Methodsmentioning

confidence: 99%

Isolation and identification of Xenorhabdus and Photorhabdus bacteria associated with entomopathogenic nematodes and their larvicidal activity against Aedes aegypti

et al. 2017

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Background Aedes aegypti is a potential vector of West Nile, Japanese encephalitis, chikungunya, dengue and Zika viruses. Alternative control measurements of the vector are needed to overcome the problems of environmental contamination and chemical resistance. Xenorhabdus and Photorhabdus are symbionts in the intestine of entomopathogenic nematodes (EPNs) Steinernema spp. and Heterorhabditis spp. These bacteria are able to produce a broad range of bioactive compounds including antimicrobial, antiparasitic, cytotoxic and insecticidal compounds. The objectives of this study were to identify Xenorhabdus and Photorhabdus isolated from EPNs in upper northern Thailand and to study their larvicidal activity against Ae. aegypti larvae.ResultsA total of 60 isolates of symbiotic bacteria isolated from EPNs consisted of Xenorhabdus (32 isolates) and Photorhabdus (28 isolates). Based on recA gene sequencing, BLASTN and phylogenetic analysis, 27 isolates of Xenorhabdus were identical and closely related to X. stockiae, 4 isolates were identical to X. miraniensis, and one isolate was identical to X. ehlersii. Twenty-seven isolates of Photorhabdus were closely related to P. luminescens akhurstii and P. luminescens hainanensis, and only one isolate was identical and closely related to P. luminescens laumondii. Xenorhabdus and Photorhabdus were lethal to Ae aegypti larvae. Xenorhabdus ehlersii bMH9.2_TH showed 100% efficiency for killing larvae of both fed and unfed conditions, the highest for control of Ae. aegypti larvae and X. stockiae (bLPA18.4_TH) was likely to be effective in killing Ae. aegypti larvae given the mortality rates above 60% at 72 h and 96 h.ConclusionsThe common species in the study area are X. stockiae, P. luminescens akhurstii, and P. luminescens hainanensis. Three symbiotic associations identified included P. luminescens akhurstii-H. gerrardi, P. luminescens hainanensis-H. gerrardi and X. ehlersii-S. Scarabaei which are new observations of importance to our knowledge of the biodiversity of, and relationships between, EPNs and their symbiotic bacteria. Based on the biological assay, X. ehlersii bMH9.2_TH begins to kill Ae. aegypti larvae within 48 h and has the most potential as a pathogen to the larvae. These data indicate that X. ehlersii may be an alternative biological control agent for Ae. aegypti and other mosquitoes.

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Section: Methodsmentioning

confidence: 99%

Isolation and identification of Xenorhabdus and Photorhabdus bacteria associated with entomopathogenic nematodes and their larvicidal activity against Aedes aegypti

et al. 2017

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“…Polymerase chain reaction (PCR) was performed with genomic DNA as a template in a total volume of 50 μl containing 10 mM Tris-HCl (pH 8.3), 50 mM KCl, 2 mM MgCl 2 , 0.2 mM dNTPs, 0.2 pmol of each primer, and Taq DNA polymerase (Promega ® ). The amplification was carried out in a DNA thermocycler (MWG BIOTECH Primuse) programmed as follows: (94 °C/4 min) 1, (94 °C/1 min, 58 °C/1 min and 72 °C/1 min) 35, (72 °C/7 min) 1 (Jiang et al 2006; Shrestha and Lee 2012). The PCR products were eluted from agarose gels using Promega ® ’s Wizard ® SV Gel and PCR Clean-Up System according to the manufacturer’s instructions.…”

Section: Methodsmentioning

confidence: 99%

Molecular identification and genetic diversity among Photorhabdus and Xenorhabdus isolates

et al. 2017

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Five bacterial strains were isolated from the hemocoel of the greater wax moth larvae (Galleria mellonella) infected with the entomopathogenic nematodes: Heterorhabditis bacteriophora HP88, Heterorhabditis indicus RM1 and Heterorhabditis sp (S1), Steinernema abbasi and Steinernema sp. (S II). Strains were identified as Photorhabdus luminescens HRM1, P. luminescens HS1, P. luminescens HP88, Xenorhabdus indica and X. nematophila ATTC19061 using 16S rDNA sequence analysis. To reveal the genetic diversity among these strains, three molecular markers (RAPD, ISSR and SRAP) were employed. RAPD analysis showed 73.8 and 54.5 polymorphism percentages for the Photorhabdus and Xenorhabdus strains, respectively. ISSR analysis resulted in 70.1 and 75.2 polymorphism percentages among the Photorhabdus and Xenorhabdus strains, respectively. The SRAP analysis indicated that 75.6 and 61.2% genetic polymorphism was detected among Photorhabdus and Xenorhabdus strains, respectively. The cluster analysis grouped the three Photorhabdus strains together in one cluster and the two Xenorhabdus strains together in another cluster indicating the phylogenetic relationships among them. The genotype-specific markers detected from the three molecular markers (RAPD, ISSR and SRAP) were sufficient to distinguish between the different bacterial strains tested and can be used in the future IBM program that could be built on the use of these strains.

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“…and/or strains. For example, Shrestha and Lee (2012) tested the oral toxicity of P. l. laumondii (TT01 strain) crude extracts against the sweet potato whitefly, Bemisia tabaci, and adults, showing they were completely lethal at 60 hr posttreatment. Orozco et al (2016) also showed that crude extracts of P. l. sonorensis have insecticidal activity against the corn earworm Helicoverpa zea.…”

Section: Insecticidal Activitymentioning

confidence: 99%

Secondary Metabolites Produced by Heterorhabditis Symbionts and Their Application in Agriculture: What We Know and What to Do Next

Stock

Kusakabe

Orozco

2017

Journal of Nematology

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Gram-negative Photorhabdus bacteria have a dual lifestyle: they are mutualists of Heterorhabditis nematodes and are pathogens of insects. Together, this nematode-bacterium partnership has been used to successfully control a wide range of agricultural insect pests. Photorhabdus produce a diverse array of small molecules that play key biological roles in regulating their dual roles. In particular, several secondary metabolites (SM) produced by this bacterium are known to play a critical role in the maintenance of a monoxenic infection in the insect host and are also known to prevent contamination of the cadaver from soil microbes and/or predation by arthropods. A few of the SM this bacteria produce have been isolated and identified, and their biological activities have also been tested in laboratory assays. Over the past two decades, analyses of the genomes of several Photorhabdus spp. have revealed the presence of SM numerous gene clusters that comprise more than 6% of these bacteria genomes. Furthermore, genome mining and characterization of biosynthetic pathways, have uncovered the richness of these compounds, which are predicted to vary across different Photorhabdus spp. and strains. Although progress has been made in the identification and function of SM genes and gene clusters, the targeted testing for the bioactivity of molecules has been scarce or mostly focused on medical applications. In this review, we summarize the current knowledge of Photorhabdus SM, emphasizing on their activity against plant pathogens and parasites. We further discuss their potential in the management of agricultural pests and the steps that need to be taken for the implementation of Photorhabdus SM in pest management.

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Oral toxicity of Photorhabdus culture media on gene expression of the adult sweetpotato whitefly, Bemisia tabaci

Cited by 24 publications

References 29 publications

Isolation and identification of Xenorhabdus and Photorhabdus bacteria associated with entomopathogenic nematodes and their larvicidal activity against Aedes aegypti

Isolation and identification of Xenorhabdus and Photorhabdus bacteria associated with entomopathogenic nematodes and their larvicidal activity against Aedes aegypti

Molecular identification and genetic diversity among Photorhabdus and Xenorhabdus isolates

Secondary Metabolites Produced by Heterorhabditis Symbionts and Their Application in Agriculture: What We Know and What to Do Next

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