scholarly journals The evolution of opsin genes in five species of mirid bugs: duplication of long-wavelength opsins and loss of blue-sensitive opsins

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Pengjun Xu ◽  
Bin Lu ◽  
Jiangtao Chao ◽  
Robert Holdbrook ◽  
Gemei Liang ◽  
...  
Keyword(s):  
Light Trapping ◽  
Phylogenetic Analyses ◽  
Management Strategies ◽  
Purifying Selection ◽  
Color Discrimination ◽  
Duplication Event ◽  
Economic Losses ◽  
Long Wavelength ◽  
Phototactic Behavior ◽  
Opsin Genes

AbstractBackgroundColor vision and phototactic behavior based on opsins are important for the fitness of insects because of their roles in foraging and mate choice. Related topics, including the duplication and loss of opsin genes, have been well investigated in insect orders such as Coleoptera, Lepidoptera, Hymenoptera, Odonata and Orthoptera, and the findings have been used to develop pest management strategies involving light trapping. Mirid bugs of Hemiptera, which are pests that cause heavy economic losses, show capacity for color discrimination and phototaxis. However, the opsins in mirid bugs remain uncharacterized. Herein, we examined five species to investigate the evolution of opsins in the family Miridae.ResultsUsing RNA-seq, we identified several contigs showing high identity with opsins, including four contigs inApolygus lucorumand three contigs each inAdelphocoris suturalis,Adelphocoris fasciaticollis,Adelphocoris lineolatusandNesidiocoris tenuis. Phylogenetic analyses indicated that one of these genes clustered with ultraviolet-sensitive (UV) opsins and that the others clustered with long-wavelength (LW) opsins, suggesting that duplication of LW opsins and loss of blue light-sensitive (B) opsins occurred in mirid bugs. The existence of introns in the LW opsins of mirid bugs suggested that the duplication events were DNA based. Both LW1 and LW2 opsins of mirid bugs were found to be under strong purifying selection. The LW1 opsins were significantly more highly expressed than the LW2 and UV opsins.ConclusionsWe identified the opsins of mirid bugs using five selected mirid species as a representative sample. Phylogenetic analyses clustered one of the genes with UV opsins and the others with LW opsins, suggesting the occurrence of LW opsin duplication and B opsin loss during the evolution of mirid bugs. Intron detection suggested that the identified duplication event was DNA based. The evidence of strong purifying selection and the relatively high expression levels suggested that these opsins exhibit fundamental functions in mirid bugs.

scholarly journals Opsin genes of select treeshrews resolve ancestral character states within Scandentia

2019 ◽  
Vol 6 (4) ◽  
pp. 182037
Author(s):  
Gwen Duytschaever ◽  
Mareike C. Janiak ◽  
Perry S. Ong ◽  
Konstans Wells ◽  
Nathaniel J. Dominy ◽  
...  
Keyword(s):  
Purifying Selection ◽  
Opsin Gene ◽  
Functional Variation ◽  
Long Wavelength ◽  
Living Fossils ◽  
Opsin Genes ◽  
Senior Synonym ◽  
Peak Sensitivity ◽  
Encoding Genes ◽  
Ancestral Character States

Treeshrews are small, squirrel-like mammals in the order Scandentia, which is nested together with Primates and Dermoptera in the superordinal group Euarchonta. They are often described as living fossils, and researchers have long turned to treeshrews as a model or ecological analogue for ancestral primates. A comparative study of colour vision-encoding genes within Scandentia found a derived amino acid substitution in the long-wavelength sensitive opsin gene ( OPN1LW ) of the Bornean smooth-tailed treeshrew ( Dendrogale melanura ). The opsin, by inference, is red-shifted by ca 6 nm with an inferred peak sensitivity of 561 nm. It is tempting to view this trait as a novel visual adaptation; however, the genetic and functional diversity of visual pigments in treeshrews is unresolved outside of Borneo. Here, we report gene sequences from the northern smooth-tailed treeshrew ( Dendrogale murina ) and the Mindanao treeshrew ( Tupaia everetti , the senior synonym of Urogale everetti ). We found that the opsin genes are under purifying selection and that D. murina shares the same substitution as its congener, a result that distinguishes Dendrogale from other treeshrews, including T. everetti. We discuss the implications of opsin functional variation in light of limited knowledge about the visual ecology of smooth-tailed treeshrews.

scholarly journals Identification and Characterization of Fungal Pathogens Causing Fruit Rot of Deciduous Holly

Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2430-2445 ◽  
Author(s):  
Shan Lin ◽  
Nancy J. Taylor ◽  
Francesca Peduto Hand
Keyword(s):  
Fungal Pathogens ◽  
Disease Incidence ◽  
Phylogenetic Analyses ◽  
Management Strategies ◽  
Morphological Characterization ◽  
Fruit Rot ◽  
Economic Losses ◽  
Yield Reduction ◽  
Inoculum Concentration ◽  
Fruit Samples

Cut branches of deciduous holly (Ilex spp. L.) harboring colorful berries are traditionally used as ornaments in holiday decorations. Since 2012, a fruit rot of unspecified cause has resulted in significant yield reduction and economic losses across Midwestern and Eastern U.S. nurseries. In this study, symptomatic fruit samples collected from nine different locations over five years were analyzed, and several fungal species were isolated. A combination of morphological characterization, multilocus phylogenetic analyses, and pathogenicity assays revealed that Alternaria alternata and Diaporthe ilicicola sp. nov. were the primary pathogens associated with symptomatic fruit. Other fungi including A. arborescens, Colletotrichum fioriniae, C. nymphaeae, Epicoccum nigrum, and species in the D. eres species complex appeared to be minor pathogens in this disease complex. In detached fruit pathogenicity assays testing the role of wounding and inoculum concentration on disease development, disease incidence and severity increased when fruit was wounded and inoculated with a higher inoculum concentration. These findings indicate that management strategies that can protect fruit from injury or reduce inoculum may lower disease levels in the field. This research established the basis for further studies on this emerging disease and the design of research-based management strategies. To our knowledge, it also represents the first report of species of Alternaria, Colletotrichum, Diaporthe, and Epicoccum causing fruit rot of deciduous holly.

scholarly journals Evidence for UV-green dichromacy in the basal hymenopteran Sirex noctilio (Siricidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Quentin Guignard ◽  
Johannes Spaethe ◽  
Bernard Slippers ◽  
Martin Strube-Bloss ◽  
Jeremy D. Allison
Keyword(s):  
Colour Vision ◽  
Compound Eye ◽  
Phylogenetic Analyses ◽  
Ultra Violet ◽  
Opsin Gene ◽  
Compound Eyes ◽  
Sirex Noctilio ◽  
Long Wavelength ◽  
Opsin Genes ◽  
Related Group

AbstractA precondition for colour vision is the presence of at least two spectral types of photoreceptors in the eye. The order Hymenoptera is traditionally divided into the Apocrita (ants, bees, wasps) and the Symphyta (sawflies, woodwasps, horntails). Most apocritan species possess three different photoreceptor types. In contrast, physiological studies in the Symphyta have reported one to four photoreceptor types. To better understand the evolution of photoreceptor diversity in the Hymenoptera, we studied the Symphyta Sirex noctilio, which belongs to the superfamily Siricoidea, a closely related group of the Apocrita suborder. Our aim was to (i) identify the photoreceptor types of the compound eye by electroretinography (ERG), (ii) characterise the visual opsin genes of S. noctilio by genomic comparisons and phylogenetic analyses and (iii) analyse opsin mRNA expression. ERG measurements revealed two photoreceptor types in the compound eye, maximally sensitive to 527 and 364 nm. In addition, we identified three opsins in the genome, homologous to the hymenopteran green or long-wavelength sensitive (LW) LW1, LW2 and ultra-violet sensitive (UV) opsin genes. The LW1 and UV opsins were found to be expressed in the compound eyes, and LW2 and UV opsins in the ocelli. The lack of a blue or short-wavelength sensitive (SW) homologous opsin gene and a corresponding receptor suggests that S. noctilio is a UV-green dichromate.

scholarly journals The Effect of Gut Bacteria on the Physiology of Red Palm Weevil, Rhynchophorus ferrugineus Olivier and Their Potential for the Control of This Pest

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 594
Author(s):  
Qian-Xia Liu ◽  
Zhi-Ping Su ◽  
Hui-Hui Liu ◽  
Sheng-Ping Lu ◽  
Bing Ma ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Management Strategies ◽  
Gut Bacteria ◽  
Economic Losses ◽  
Rhynchophorus Ferrugineus ◽  
Intestinal Immunity ◽  
Red Palm Weevil ◽  
Nutrient Metabolism ◽  
Palm Weevil

Red Palm Weevil (RPW), Rhynchophorus ferrugineus Olivier, is a notorious pest, which infests palm trees and has caused great economic losses worldwide. At present, insecticide applications are still the main way to control this pest. However, pesticide resistance has been detected in the field populations of RPW. Thus, future management strategies based on the novel association biological control need be developed. Recent studies have shown that the intestinal tract of RPW is often colonized by multiple microbial species as mammals and model insects, and gut bacteria have been found to promote the growth, development and immune activity of RPW larvae by modulating nutrient metabolism. Furthermore, two peptidoglycan recognition proteins (PGRPs), PGRP-LB and PGRP-S1, can act as the negative regulators to modulate the intestinal immunity to maintain the homeostasis of gut bacteria in RPW larvae. Here, we summarized the current knowledge on the gut bacterial composition of RPW and their impact on the physiological traits of RPW larvae. In contrast with metazoans, it is much easier to make genetic engineered microbes to produce some active molecules against pests. From this perspective, because of the profound effects of gut bacteria on host phenotypes, it is promising to dissect the molecular mechanisms behind their effect on host physiology and facilitate the development of microbial resource-based management methods for pest control.

scholarly journals Diversity of Colletotrichum Species Associated with Anthracnose Disease in Tropical Fruit Crops—A Review

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 297
Author(s):  
Latiffah Zakaria
Keyword(s):  
Management Strategies ◽  
Economic Losses ◽  
Fruit Crops ◽  
Tropical Fruit ◽  
Colletotrichum Species ◽  
Adequate Knowledge ◽  
Dragon Fruit ◽  
Causative Agents ◽  
Colletotrichum Spp ◽  
Fruit Plantations

In tropical fruit crops, anthracnose is mainly caused by species belonging to the fungal genus, Colletotrichum. These phytopathogens can infect several parts of the fruit crops; however, infection during postharvest or ripening stages is responsible for major economic losses. Due to the formation of black to dark brown sunken lesions on the fruit surface, anthracnose reduces fruit quality and marketability. Among the most common tropical fruit crops susceptible to anthracnose are mango, papaya, banana, avocado, guava, and dragon fruit; these are economically relevant products in many developing countries. It is important to document that the newly recorded Colletotrichum spp. associated with fruit anthracnose can infect multiple hosts, but some species may be host-specific. By using multiple markers, many phylogenetic species of Colletotrichum have been reported as anthracnose-causing pathogens. Taking into account that disease management strategies strongly rely on adequate knowledge of the causative agents, updated information on Colletotrichum species and the hazard posed by the most recently identified species in tropical fruit plantations and harvested fruits becomes vital. Besides, the newly recorded species may be important for biosecurity and should be listed as quarantine pathogens, considering that tropical fruits are traded worldwide.

scholarly journals Metagenomic analyses and genetic diversity of Tomato leaf curl Arusha virus affecting tomato plants in Kenya

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Edith Khamonya Avedi ◽  
Adedapo Olutola Adediji ◽  
Dora Chao Kilalo ◽  
Florence Mmogi Olubayo ◽  
Isaac Macharia ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Selection Pressure ◽  
Management Strategies ◽  
Purifying Selection ◽  
Tomato Leaf ◽  
Amino Acid Sequences ◽  
Virus Population ◽  
Tomato Production ◽  
Tomato Leaf Curl ◽  
Leaf Curl

Abstract Background Tomato production is threatened worldwide by the occurrence of begomoviruses which are associated with tomato leaf curl diseases. There is little information on the molecular properties of tomato begomoviruses in Kenya, hence we investigated the population and genetic diversity of begomoviruses associated with tomato leaf curl in Kenya. Methods Tomato leaf samples with virus-like symptoms were obtained from farmers’ field across the country in 2018 and Illumina sequencing undertaken to determine the genetic diversity of associated begomoviruses. Additionally, the occurrence of selection pressure and recombinant isolates within the population were also evaluated. Results Twelve complete begomovirus genomes were obtained from our samples with an average coverage of 99.9%. The sequences showed 95.7–99.7% identity among each other and 95.9–98.9% similarities with a Tomato leaf curl virus Arusha virus (ToLCArV) isolate from Tanzania. Analysis of amino acid sequences showed the highest identities in the regions coding for the coat protein gene (98.5–100%) within the isolates, and 97.1–100% identity with the C4 gene of ToLCArV. Phylogenetic algorithms clustered all Kenyan isolates in the same clades with ToLCArV, thus confirming the isolates to be a variant of the virus. There was no evidence of recombination within our isolates. Estimation of selection pressure within the virus population revealed the occurrence of negative or purifying selection in five out of the six coding regions of the sequences. Conclusions The begomovirus associated with tomato leaf curl diseases of tomato in Kenya is a variant of ToLCArV, possibly originating from Tanzania. There is low genetic diversity within the virus population and this information is useful in the development of appropriate management strategies for the disease in the country.

scholarly journals RNAi of a Putative Grapevine Susceptibility Gene as a Possible Downy Mildew Control Strategy

2021 ◽  
Vol 12 ◽  
Author(s):  
Demetrio Marcianò ◽  
Valentina Ricciardi ◽  
Elena Marone Fassolo ◽  
Alessandro Passera ◽  
Piero Attilio Bianco ◽  
...  
Keyword(s):  
Gene Expression ◽  
Downy Mildew ◽  
Disease Severity ◽  
Fungal Pathogens ◽  
Management Strategies ◽  
Susceptibility Gene ◽  
Plasmopara Viticola ◽  
Pinot Noir ◽  
Economic Losses ◽  
Reproductive Structures

Downy mildew, caused by the oomycete Plasmopara viticola, is one of the diseases causing the most severe economic losses to grapevine (Vitis vinifera) production. To date, the application of fungicides is the most efficient method to control the pathogen and the implementation of novel and sustainable disease control methods is a major challenge. RNA interference (RNAi) represents a novel biotechnological tool with a great potential for controlling fungal pathogens. Recently, a candidate susceptibility gene (VviLBDIf7) to downy mildew has been identified in V. vinifera. In this work, the efficacy of RNAi triggered by exogenous double-stranded RNA (dsRNA) in controlling P. viticola infections has been assessed in a highly susceptible grapevine cultivar (Pinot noir) by knocking down VviLBDIf7 gene. The effects of dsRNA treatment on this target gene were assessed by evaluating gene expression, disease severity, and development of vegetative and reproductive structures of P. viticola in the leaf tissues. Furthermore, the effects of dsRNA treatment on off-target (EF1α, GAPDH, PEPC, and PEPCK) and jasmonic acid metabolism (COI1) genes have been evaluated. Exogenous application of dsRNA led to significant reductions both in VviLBDIf7 gene expression, 5 days after the treatment, and in the disease severity when artificial inoculation was carried out 7 days after dsRNA treatments. The pathogen showed clear alterations to both vegetative (hyphae and haustoria) and reproductive structures (sporangiophores) that resulted in stunted growth and reduced sporulation. Treatment with dsRNA showed signatures of systemic activity and no deleterious off-target effects. These results demonstrated the potential of RNAi for silencing susceptibility factors in grapevine as a sustainable strategy for pathogen control, underlying the possibility to adopt this promising biotechnological tool in disease management strategies.

scholarly journals Molecular Phylogenetics and Evolutionary Analysis of a Highly Recombinant Begomovirus, Cotton Leaf Curl Multan Virus and Associated Satellites

2021 ◽  
Author(s):  
Tahir Farooq ◽  
Muhammad Umar ◽  
Xiaoman She ◽  
Yafei Tang ◽  
Zifu He
Keyword(s):  
Molecular Phylogenetics ◽  
Management Strategies ◽  
Purifying Selection ◽  
Genomic Diversity ◽  
Cotton Leaf ◽  
Evolutionary Analysis ◽  
Cotton Production ◽  
Evolutionary Patterns ◽  
Satellite Sequences ◽  
Leaf Curl

Abstract Cotton leaf curl Multan virus (CLCuMuV) and its associated satellites are a major part of the cotton leaf curl disease (CLCuD) caused by the begomovirus species complex. Despite the implementation of potential disease management strategies, the incessant resurgence of resistance-breaking variants of CLCuMuV imposes a continuous threat to cotton production. Here, we present a focused effort to map the geographical prevalence, genomic diversity and molecular evolutionary endpoints that enhance disease complexity by facilitating the successful adaptation of CLCuMuV populations to the diversified ecosystems. Our results demonstrate that CLCuMuV populations are predominantly distributed in China while the majority of alphasatellites and betasatellites exist in Pakistan. We demonstrate that together with frequent recombination, an uneven genetic variation mainly drives CLCuMuV and its satellite’s virulence and evolvability. However, the pattern and distribution of recombination breakpoints greatly vary among viral and satellite sequences. The CLCuMuV, Cotton leaf curl Multan alphasatellite (CLCuMuA) and Cotton leaf curl Multan betasatellite (CLCuMuB) populations arising from distinct regions exhibit high mutation rates. Though evolutionary linked, these populations are independently evolving under strong purifying selection. These findings will facilitate to comprehensively understand the standing genetic variability and evolutionary patterns existing among CLCuMuV populations across major cotton-producing regions of the world.

scholarly journals Detecting and Differentiating Phytoplasmas Belonging to Subgroups 16SrIV-A and 16SrIV-D Associated With Lethal Declines of Palms in Florida Using qPCR and High-Resolution Melt Analysis (HRMA)

Plant Disease ◽  
2017 ◽  
Vol 101 (8) ◽  
pp. 1449-1454 ◽  
Author(s):  
Brian W. Bahder ◽  
Ericka E. Helmick ◽  
Nigel A. Harrison
Keyword(s):  
High Resolution ◽  
Sequence Data ◽  
Management Strategies ◽  
Economic Losses ◽  
High Resolution Melt ◽  
High Resolution Melt Analysis ◽  
Melting Temperatures ◽  
Detection And Identification ◽  
Lethal Yellowing ◽  
Sufficient Variation

Lethal yellowing (LY) and Texas Phoenix palm decline (TPPD) are two important phytoplasma diseases of palms in Florida. Both have been responsible for major economic losses historically and remain a constant threat to the sustainability of palm production in the landscaping and nursery industries in Florida. These two diseases cause rapid, lethal decline in afflicted palms, so rapid detection and identification is crucial to implement appropriate management strategies to reduce further spread and losses. In this study, a qPCR assay was developed to detect and identify the causal agents of LY and TPPD. Based on sequence data of the 16S gene for the 16SrIV-A phytoplasma (LY) and the 16SrIV-D phytoplasma (TPPD), two regions were identified in the gene that possessed sufficient variation to yield amplicons with measurable differences in melting temperature based on high resolution melt analysis (HRMA). One region was in the 5′ region and the other was located in the 3′ region of the gene. Products from both regions yielded amplicons with significantly different melting temperatures between the two phytoplasma strains. This research allows for the detection and identification of phytoplasmas in palms rapidly by eliminating many lengthy and post-PCR steps commonly used in phytoplasma identification.

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