scholarly journals Transcriptome and microbiome of coconut rhinoceros beetle (Oryctes rhinoceros) larvae

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Matan Shelomi ◽  
Shih-Shun Lin ◽  
Li-Yu Liu
Keyword(s):  
Pacific Islands ◽  
Plant Cell Wall ◽  
Fat Body ◽  
Molecular Data ◽  
Cell Wall Degrading Enzymes ◽  
Tropical Asia ◽  
Oryctes Rhinoceros ◽  
Rhinoceros Beetle ◽  
Microbial Symbionts ◽  
Decaying Wood

Abstract Background The coconut rhinoceros beetle, Oryctes rhinoceros, is a major pest of palm crops in tropical Asia and the Pacific Islands. Little molecular data exists for this pest, impeding our ability to develop effective countermeasures and deal with the species’ growing resistance to viral biocontrols. We present the first molecular biology analyses of this species, including a metagenomic assay to understand the microbiome of different sections of its digestive tract, and a transcriptomics assay to complement the microbiome data and to shed light on genes of interest like plant cell wall degrading enzymes and immunity and xenobiotic resistance genes. Results The gut microbiota of Oryctes rhinoceros larvae is quite similar to that of the termite gut, as both species feed on decaying wood. We found the first evidence for endogenous beta-1,4-endoglucanase in the beetle, plus evidence for microbial cellobiase, suggesting the beetle can degrade cellulose together with its gut microfauna. A number of antimicrobial peptides are expressed, particularly by the fat body but also by the midgut and hindgut. Conclusions This transcriptome provides a wealth of data about the species’ defense against chemical and biological threats, has uncovered several potentially new species of microbial symbionts, and significantly expands our knowledge about this pest.

scholarly journals Transcription Profile and Genomic Variations of Oryctes Rhinoceros Nudivirus in Coconut Rhinoceros Beetles

2020 ◽  
Vol 94 (22) ◽  
Author(s):  
Kayvan Etebari ◽  
Rhys Parry ◽  
Marie Joy B. Beltran ◽  
Michael J. Furlong
Keyword(s):  
Gene Expression ◽  
Southeast Asia ◽  
Pacific Islands ◽  
Biocontrol Agent ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Content Type ◽  
Oryctes Rhinoceros ◽  
Rhinoceros Beetle ◽  
The Pacific

ABSTRACT Oryctes rhinoceros nudivirus (OrNV) is a double-stranded DNA (dsDNA) virus which has been used as a biocontrol agent to suppress the coconut rhinoceros beetle (Oryctes rhinoceros) in Southeast Asia and the Pacific Islands. A new wave of O. rhinoceros incursions in Oceania is thought to be related to the presence of low-virulence isolates of OrNV or virus-tolerant haplotypes of beetles. In this study, chronically infected beetles were collected from Philippines, Fiji, Papua New Guinea (PNG), and the Solomon Islands (SI). RNA sequencing (RNA-seq) was performed to investigate the global viral gene expression profiles and for comparative genomic analysis of structural variations. Maximum likelihood phylogenic analysis indicated that OrNV strains from the SI and Philippines are closely related, while OrNV strains from PNG and Fiji formed a distinct adjacent clade. We detected several polymorphic sites with a frequency higher than 35% in 892 positions of the viral genome. Nonsynonymous mutations were detected in several hypothetical proteins and 15 nudivirus core genes, such as gp034, lef-8, lef-4, and vp91. We found limited evidence of variation in viral gene expression among geographic populations. Only a few genes, such as gp01, gp022, and gp107, were differentially expressed among different strains. Additionally, small RNA sequencing from the SI population suggested that OrNV is targeted by the host RNA interference (RNAi) response with abundant 21-nucleotide small RNAs. Some of these genomic changes are specific to the geographic population and could be related to particular phenotypic characteristics of the strain, such as viral pathogenicity or transmissibility, and this requires further investigation. IMPORTANCE Oryctes rhinoceros nudivirus has been an effective biocontrol agent against the coconut rhinoceros beetle in Southeast Asia and the Pacific Islands for decades. The recent outbreak of these beetles in many South Pacific islands has had a significant impact on livelihoods in the region. It has been suggested that the resurgence and spread of the pest are related to the presence of low-virulence isolates of OrNV or virus-tolerant haplotypes of beetles. We examined viral genomic and transcriptional variations in chronically infected beetles from different geographical populations. A high number of polymorphic sites among several geographical strains of OrNV were identified, but potentially only a few of these variations in the genome are involved in functional changes and can potentially alter the typical function. These findings provide valuable resources for future studies to improve our understanding of the OrNV genetic variations in different geographic regions and their potential link to virus pathogenicity.

scholarly journals Culturing-Enriched Metabarcoding Analysis of the Oryctes rhinoceros Gut Microbiome

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 782
Author(s):  
Matan Shelomi ◽  
Ming-Ju Chen
Keyword(s):  
Bacillus Cereus ◽  
Fat Body ◽  
Cellulase Activity ◽  
Gut Contents ◽  
Cellulolytic Activity ◽  
Gut Microbes ◽  
Oryctes Rhinoceros ◽  
Rhinoceros Beetle ◽  
Unculturable Bacteria ◽  
Insect Gut

Wood-feeding insects should have a source of enzymes like cellulases to digest their food. These enzymes can be produced by the insect, or by microbes living in the wood and/or inside the insect gut. The coconut rhinoceros beetle, Oryctes rhinoceros, is a pest whose digestive microbes are of considerable interest. This study describes the compartments of the O. rhinoceros gut and compares their microbiomes using culturing-enriched metabarcoding. Beetle larvae were collected from a coconut grove in southern Taiwan. Gut contents from the midgut and hindgut were plated on nutrient agar and selective carboxymethylcellulose agar plates. DNA was extracted from gut and fat body samples and 16S rDNA metabarcoding performed to identify unculturable bacteria. Cellulase activity tests were performed on gut fluids and microbe isolates. The midgut and hindgut both showed cellulolytic activity. Bacillus cereus, Citrobacter koseri, and the cellulolytic fungus Candida xylanilytica were cultured from both gut sections in most larvae. Metabarcoding did not find Bacillus cereus, and found that either Citrobacter koseri or Paracoccus sp. were the dominant gut microbes in any given larva. No significant differences were found between midgut and hindgut microbiomes. Bacillus cereus and Citrobacter koseri are common animal gut microbes frequently found in Oryctes rhinoceros studies while Candida xylanilytica and the uncultured Paracoccus sp. had not been identified in this insect before. Some or all of these may well have digestive functions for the beetle, and are most likely acquired from the diet, meaning they may be transient commensalists rather than obligate mutualists. Broader collection efforts and tests with antibiotics will resolve ambiguities in the beetle–microbe interactions.

scholarly journals The origin of fungi-culture in termites was associated with a shift to a mycolytic gut bacteria community

2018 ◽  
Author(s):  
Haofu Hu ◽  
Rafael Rodrigues da Costa ◽  
Bo Pilgaard ◽  
Morten Schiøtt ◽  
Lene Lange ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Proteolytic Enzymes ◽  
Gut Bacteria ◽  
Cell Wall Degrading Enzymes ◽  
Fungal Cell ◽  
Degrading Enzymes ◽  
Termite Gut ◽  
Decaying Wood ◽  
And Function

AbstractTermites forage on a range of substrates, and it has been suggested that diet shapes the composition and function of termite gut bacterial communities. Through comparative analyses of gut metagenomes in nine termite species with distinct diets, we characterise bacterial community compositions and identify biomass-degrading enzymes and the bacterial taxa that encode them. We find that fungus-growing termite guts are enriched in fungal cell wall-degrading and proteolytic enzymes, while wood-feeding termite gut communities are enriched for plant cell wall-degrading enzymes. Interestingly, wood-feeding termite gut bacteria code for abundant chitinolytic enzymes, suggesting that fungal biomass within the decaying wood likely contributes to gut bacteria or termite host nutrition. Across diets, the dominant biomass-degrading enzymes are predominantly coded for by the most abundant bacterial taxa, suggesting tight links between diet and gut community composition, with the most marked shift being the communities coding for the mycolytic capacity of the fungus-growing termite gut.

scholarly journals Horizontal Gene Transfer in Nematodes: A Catalyst for Plant Parasitism?

2011 ◽  
Vol 24 (8) ◽  
pp. 879-887 ◽  
Author(s):  
Annelies Haegeman ◽  
John T. Jones ◽  
Etienne G. J. Danchin
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Plant Cell Wall ◽  
Molecular Data ◽  
Parasitic Nematodes ◽  
Cell Wall Degrading Enzymes ◽  
Feeding Site ◽  
Plant Parasitism ◽  
Bacteria And Fungi ◽  
Plant Parasitic

The origin of plant parasitism within the phylum Nematoda is intriguing. The ability to parasitize plants has originated independently at least three times during nematode evolution and, as more molecular data has emerged, it has become clear that multiple instances of horizontal gene transfer (HGT) from bacteria and fungi have played a crucial role in the nematode's adaptation to this new lifestyle. The first reported HGT cases in plant-parasitic nematodes were genes encoding plant cell wall–degrading enzymes. Other putative examples of HGT were subsequently described, including genes that may be involved in the modulation of the plant's defense system, the establishment of a nematode feeding site, and the synthesis or processing of nutrients. Although, in many cases, it is difficult to pinpoint the donor organism, candidate donors are usually soil dwelling and are either plant-pathogenic or plant-associated microorganisms, hence occupying the same ecological niche as the nematodes. The exact mechanisms of transfer are unknown, although close contacts with donor microorganisms, such as symbiotic or trophic interactions, are a possibility. The widespread occurrence of horizontally transferred genes in evolutionarily independent plant-parasitic nematode lineages suggests that HGT may be a prerequisite for successful plant parasitism in nematodes.

scholarly journals Aggregation Pheromone of the Guam Strain of Coconut Rhinoceros Beetle, Oryctes Rhinoceros, and Revision of Stereochemistry

2021 ◽  
Author(s):  
David R Hall ◽  
Steven J Harte ◽  
Dudley I Farman ◽  
Mark Ero ◽  
Alfred Pokana
Keyword(s):  
Aggregation Pheromone ◽  
Field Trapping ◽  
Ethyl Esters ◽  
Male And Female ◽  
Tropical Asia ◽  
Oryctes Rhinoceros ◽  
Rhinoceros Beetle ◽  
Virgin Male ◽  
Female Specific ◽  
Male Specific

Abstract The coconut rhinoceros beetle, Oryctes rhinoceros (Linnaeus 1758) (Coleoptera: Scarabaeidae: Dynastinae) (CRB), is endemic to tropical Asia where it damages both coconut and oil palm. A new invasion by CRB occurred on Guam in 2007 and eradication attempts failed using commonly applied O. rhinoceros nudivirus (OrNV) isolates. This and subsequent invasive outbreaks were found to have been caused by a previously unrecognized haplotype, CRB-G, which appeared to be tolerant to OrNV. The male-produced aggregation pheromone of the endemic, susceptible strain of O. rhinoceros (CRB-S) was previously identified as ethyl 4-methyloctanoate. There were anecdotal reports that the commercial lures containing this compound were not attractive to CRB-G and the aim of this work was to identify the pheromone of CRB-G. Initial collections of volatiles from virgin male and female CRB-G adults failed to show any male- or female-specific compounds as candidate pheromone components. Only after five months were significant quantities of ethyl 4-methyloctanoate and 4-methyloctanoic acid produced by males but not by females. No other male-specific compounds could be detected, in particular methyl 4-methyloctanoate, 4-methyl-1-octanol or 4-methyl-1-octyl acetate, compounds identified in volatiles from some other species of Oryctes. Ethyl 4-methyloctanoate elicited a strong electroantennogram response from both male and female CRB-G, but these other compounds, including 4-methyloctanoic acid, did not. The enantiomers of ethyl 4-methyloctanoate and 4-methyloctanoic acid were conveniently prepared by enzymatic resolution of the commercially-available acid, and the enantiomers of the acid, but not the ester, could be separated by gas chromatography on an enantiospecific cyclodextrin phase. Using this approach, both the ethyl 4-methyloctanoate and the 4-methyloctanoic acid produced by male CRB-G were shown to be exclusively the (R)-enantiomers whereas previous reports had suggested male CRB-S produced the (S)-enantiomers. However, re-examination of the ester and acid produced by male CRB-S showed that these were also the (R)-enantiomers. In field trapping experiments, both racemic and ethyl (R)-4-methyloctanoate were highly attractive to both male and female CRB-G. The (S)-enantiomer and the corresponding acids were only weakly attractive. Addition of racemic 4-methyloctanoic acid to ethyl 4-methyloctanoate did significantly increase attractiveness, but addition of (R)- or (S)-4-methyloctanoic acid to the corresponding ethyl esters did not. Reasons for the previous misassignment of the configuration of the components of the CRB-S pheromone are discussed along with the practical implications of these results.

scholarly journals Diverse Host Immune Responses of Different Geographical Populations of the Coconut Rhinoceros Beetle to Oryctes Rhinoceros Nudivirus (OrNV) Infection

2021 ◽  
Author(s):  
Kayvan Etebari ◽  
Maria Gharuka ◽  
Sassan Asgari ◽  
Michael J. Furlong
Keyword(s):  
Immune Responses ◽  
Pacific Islands ◽  
Biocontrol Agent ◽  
New Wave ◽  
Oryctes Rhinoceros ◽  
Host Immune Responses ◽  
Rhinoceros Beetle ◽  
Double Stranded Dna ◽  
The Pacific ◽  
Geographical Populations

Oryctes rhinoceros nudivirus (OrNV) is a double-stranded DNA (dsDNA) virus which has been used as a biocontrol agent to suppress coconut rhinoceros beetle (CRB) in the Pacific Islands. Recently a new wave of CRB incursions in Oceania is thought to be related to the presence of low-virulence isolates of OrNV or virus-tolerant haplotypes of beetles (CRB-G).

scholarly journals Identification of Components of the Aggregation Pheromone of the Guam Strain of Coconut Rhinoceros Beetle, Oryctes rhinoceros, and Determination of Stereochemistry

2021 ◽  
Author(s):  
David R. Hall ◽  
Steven J. Harte ◽  
Dudley I. Farman ◽  
Mark Ero ◽  
Alfred Pokana
Keyword(s):  
Aggregation Pheromone ◽  
Solomon Islands ◽  
Field Trapping ◽  
Ethyl Esters ◽  
Male And Female ◽  
Tropical Asia ◽  
Oryctes Rhinoceros ◽  
Rhinoceros Beetle ◽  
The Difference ◽  
Female Specific

AbstractThe coconut rhinoceros beetle, Oryctes rhinoceros (Linnaeus 1758) (Coleoptera: Scarabaeidae: Dynastinae) (CRB), is endemic to tropical Asia where it damages both coconut and oil palm. A new invasion by CRB occurred on Guam in 2007 and eradication attempts failed using commonly applied Oryctes rhinoceros nudivirus (OrNV) isolates. This and subsequent invasive outbreaks were found to have been caused by a previously unrecognized haplotype, CRB-G, which appeared to be tolerant to OrNV. The male-produced aggregation pheromone of the endemic, susceptible strain of O. rhinoceros (CRB-S) was previously identified as ethyl 4-methyloctanoate. Following reports from growers that commercial lures containing this compound were not attractive to CRB-G, the aim of this work was to identify the pheromone of CRB-G. Initial collections of volatiles from virgin male and female CRB-G adults from the Solomon Islands failed to show any male- or female-specific compounds as candidate pheromone components. Only after five months were significant quantities of ethyl 4-methyloctanoate and 4-methyloctanoic acid produced by males but not by females. No other male-specific compounds could be detected, in particular methyl 4-methyloctanoate, 4-methyl-1-octanol, or 4-methyl-1-octyl acetate, compounds identified in volatiles from some other species of Oryctes. Ethyl 4-methyloctanoate elicited a strong electroantennogram response from both male and female CRB-G, but these other compounds, including 4-methyloctanoic acid, did not. The enantiomers of ethyl 4-methyloctanoate and 4-methyloctanoic acid were conveniently prepared by enzymatic resolution of the commercially-available acid, and the enantiomers of the acid, but not the ester, could be separated by gas chromatography on an enantioselective cyclodextrin phase. Using this approach, both ethyl 4-methyloctanoate and 4-methyloctanoic acid produced by male CRB-G were shown to be exclusively the (R)-enantiomers whereas previous reports had suggested male O. rhinoceros produced the (S)-enantiomers. However, re-examination of the ester and acid produced by male CRB-S from Papua New Guinea showed that these were also the (R)-enantiomers. In field trapping experiments carried out in the Solomon Islands, both racemic and ethyl (R)-4-methyloctanoate were highly attractive to both male and female CRB-G beetles. The (S)-enantiomer and the corresponding acids were only weakly attractive. The addition of racemic 4-methyloctanoic acid to ethyl 4-methyloctanoate did significantly increase attractiveness, but the addition of (R)- or (S)-4-methyloctanoic acid to the corresponding ethyl esters did not. Possible reasons for the difference in assignment of configuration of the components of the CRB pheromone are discussed along with the practical implications of these results.

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