International Journal of Biological Macromolecules, 2021
The present study demonstrated that chitin-based nanofibers (CNFs) trigger the chitinase genes (P... more The present study demonstrated that chitin-based nanofibers (CNFs) trigger the chitinase genes (PGIP1 and CaChi2), while elevating salicylic acid that can protect plants against pathogens. Cross-talk between this genetic induction and salicylic-acid-mediated immune response was also observed, which may arm a plant against multiple pathovars. Crab and mushroom based CNFs were synthesized by electrospinning and ball milling techniques. Plants (mung bean, Vigna radiata) (pepper, Capsicum annuum) were pre-inoculated with CNFs and treated with the pathogens Scrolotium rolfsii for pepper and Macrophomina phaseolina for mung bean and shrimp-based CNFs were used as a control. Treated plants had elevated levels of chitinase genes in response to CNFs at inoculation concentrations <10 mg/mL both in soil and media, to protect them against the pathogenic fungal disease. After 24 h of exposure to the pathogens, qRT-PCR showed genes class II chitinase gene (CaChi2) and polygalacturonase inhibitor protein 1 (PGIP1) to be up-regulated in both root and shoot at 0.1 and 1 mg/mL of inoculation, respectively. The ball milled mushroom CNFs were sufficient to trigger the membrane based enzymes with less diameter (≥15 nm) to be most efficient versus others. In vitro analysis showed IC50 of ball milled mushroom CNFs to be most efficient in limiting the growth of fungal biomass. Further trigger-like effects were prominent in reducing pathogenic fungal spread in both species.
Forest bug (red-legged shieldbug, Pentatoma rufipes) is a commonly occurring and widespread shiel... more Forest bug (red-legged shieldbug, Pentatoma rufipes) is a commonly occurring and widespread shieldbug species in the UK. It is particularly associated with woodland habitats and may remain in woodlands throughout the year, feeding on tree species such as oak, beech and hazel. However, forest bug also occurs in orchards and is emerging as an important pest of tree fruit in northern Europe. In recent years – particularly since the withdrawal of chlorpyrifos in 2016 – UK top-fruit agronomists have found increasing numbers of forest bugs in and around orchards. Their feeding activity on developing fruits is being linked with pitting and distortion damage to apples and pears. There has been limited scientific research into the ecology and control of this species, but some Belgian, Swiss and German studies provide valuable information on the timing of the life cycle and the effects of plant protection products. No information is available linking UK local population levels and activity wi...
This chapter reviews the transmission of plant viruses by aphids, with particular emphasis on the... more This chapter reviews the transmission of plant viruses by aphids, with particular emphasis on the virus-vector interactions, the attributes that make aphids such well-adapted vectors, the different modes of transmission, the determinants of transmissibility, the factors affecting virus acquisition and inoculation, control methods (e.g. use of virus-resistant or aphid-resistant genotypes, elimination of virus sources, and eradication of weeds, infected plants and volunteer plants), and prevention or reduction of virus spread by plant spacing and chemical, biological, cultural and integrated control of vectors among others.
... Virus acquisition must therefore be estimated by inoculation and subsequent symp-tom expressi... more ... Virus acquisition must therefore be estimated by inoculation and subsequent symp-tom expression. ... Want, JPH van der, 1954. Onderzoekingen over virusz-lekten van de boon (Phaseolus vulgaris L.). D. Phil. Thesis, Wageningen Agricultural University, The Netherlands. ...
The emergence of resistance mechanisms to, and revocation of, many insecticides used in the contr... more The emergence of resistance mechanisms to, and revocation of, many insecticides used in the control of the polyphagus aphid pest, Myzus persicae (Sulzer), has increased the pressure to develop novel approaches for the control of the pest in many crops. Kaolin-based particle films provide a physical barrier against insect pests and show considerable potential for controlling M. persicae. We conducted a series of laboratory experiments to investigate the mode of action of kaolin against aphids. The material appeared to have no direct effect on M. persicae; spraying adult aphids with aqueous kaolin suspension had no significant impact on their subsequent survival or reproduction on untreated plants. Similarly, when aphids were placed on kaolin-treated host-plants (Brassica oleracea), their performance (survival, growth rate and reproduction) was not significantly different from aphids on untreated plants. However, when M. persicae were given a choice between kaolin-treated and untreate...
The worldwide invasive insect pest, Drosophila suzukii Matsumura (spotted-wing Drosophila), lays ... more The worldwide invasive insect pest, Drosophila suzukii Matsumura (spotted-wing Drosophila), lays eggs in soft and stone fruit before harvest. Hatched larvae cause fruit collapse and significant economic losses. Current control methods rely primarily on foliar insecticide applications, which are not sustainable long-term solutions due to regulatory restrictions and the risk of insecticide resistance developing. We showed before that D. suzukii were deterred from laying eggs on artificial media previously visited by its sister species—Drosophila melanogaster. In the current study, laboratory choice test experiments were conducted to identify which D. melanogaster life stage (eggs, larvae, or adult) deterred D. suzukii oviposition. We demonstrated that the presence of live D. melanogaster larvae on the egg-laying media consistently deterred D. suzukii oviposition. Drosophila melanogaster cuticular hydrocarbons (CHCs) were examined as candidate for the oviposition deterrent. CHCs of lar...
ABSTRACTWoolly apple aphid (WAA, Eriosoma lanigerum Hausmann) (Hemiptera: Aphididae), is a major ... more ABSTRACTWoolly apple aphid (WAA, Eriosoma lanigerum Hausmann) (Hemiptera: Aphididae), is a major pest of apple trees (Malus domestica, order Rosales) and is critical to the economics of the apple industry in most parts of the world. Here, we generated a chromosome-level genome assembly of WAA – representing the first genome sequence from the aphid subfamily Eriosomatinae – using a combination of 10X Genomics linked-reads and in vivo Hi-C data. The final genome assembly is 327 Mb, with 91% of the assembled sequences anchored into six chromosomes. The contig and scaffold N50 values are 158 kb and 71 Mb, respectively, and we predicted a total of 28,186 protein-coding genes. The assembly is highly complete, including 97% of conserved arthropod single-copy orthologues based on BUSCO analysis. Phylogenomic analysis of WAA and nine previously published aphid genomes, spanning four aphid tribes and three subfamilies, reveals that the tribe Eriosomatini (represented by WAA) is recovered as a...
DL-β-aminobutyric acid (BABA) is a non-protein amino acid that is an effective inducer of resista... more DL-β-aminobutyric acid (BABA) is a non-protein amino acid that is an effective inducer of resistance against a variety of plant pathogens. However, examples of BABA-induced resistance against insect herbivores have not been reported. We applied BABA as a soil drench to legumes and monitored its effects on the pea aphid Acyrthosiphon pisum (Harris). On tic bean (Vicia faba var. minor), BABA increased aphid mortality, caused a reduction in the mean relative growth rate of individual insects and lessened the intrinsic rate of population increase (rm). BABA also caused significant reductions in the growth rate of A. pisum on pea (Pisum sativa), broad bean (Vicia faba var. major), runner bean (Phaseolus coccineus), red clover (Trifolium pratense) and alfalfa (Medicago sativa). No direct toxic effects of BABA against A. pisum were found, and no phytotoxic effects that may have caused a reduction in aphid performance were detected. Possible mechanisms behind this BABA-induced inhibition of...
ABSTRACT dl-β-Aminobutyric acid (BABA) is a nonprotein amino acid that can enhance defences in a ... more ABSTRACT dl-β-Aminobutyric acid (BABA) is a nonprotein amino acid that can enhance defences in a variety of plants against a wide range of pathogens. BABA can also reduce infestation by phytopathogenic nematodes and has recently been shown to suppress the growth of aphids feeding on legumes. This investigation examined the effect of applying BABA as a root drench to a range of Brassicaceae, including Arabidopsis thaliana, on the performance of two species of aphid (Myzus persicae and Brevicoryne brassicae) and the larvae of two species of Lepidoptera (Trichoplusia ni and Plutella xylostella). Application of BABA reduced the performance of all four insect species, and inhibition of insects occurred on all the plants tested. The results illustrate that BABA-induced resistance (BABA-IR) can affect generalist and specialist insect herbivores and inhibit insects feeding with mandibulate as well as sap-feeding mouthparts. The BABA-induced suppression of B. brassicae and P. xylostella feeding on A. thaliana provides a means to further examine the mechanisms of BABA-IR to insects using this model plant.
Increased industrial processes have introduced emerging toxic pollutants into the environment. Ph... more Increased industrial processes have introduced emerging toxic pollutants into the environment. Phytoremediation is considered to be a very useful, economical and ecofriendly way of controlling these pollutants, however, certain pollutants can potentially travel through the food chain and accumulate at hazardous levels. Four isomers of dinitrotoluenes (DNT) were investigated and observed their potential toxicity towards A. thaliana. Two different aphid species (generalist and specialist) were allowed to feed on plants treated with DNTs and toxicity to aphids determined. Reduced metabolites of DNT (in both plant and aphids) were recovered and quantified through GC-MS analyses. 2,6-DNT was observed to be the toxic of the DNTs tested. Complete metabolism of DNTs to their reduced products was never achieved for higher concentrations. Regioselectivity was observed in the case of 2,4-DNT, with 4A2NT as the dominant isomer. Feeding aphids showed a similar toxicity pattern for DNT isomers as...
International Journal of Biological Macromolecules, 2021
The present study demonstrated that chitin-based nanofibers (CNFs) trigger the chitinase genes (P... more The present study demonstrated that chitin-based nanofibers (CNFs) trigger the chitinase genes (PGIP1 and CaChi2), while elevating salicylic acid that can protect plants against pathogens. Cross-talk between this genetic induction and salicylic-acid-mediated immune response was also observed, which may arm a plant against multiple pathovars. Crab and mushroom based CNFs were synthesized by electrospinning and ball milling techniques. Plants (mung bean, Vigna radiata) (pepper, Capsicum annuum) were pre-inoculated with CNFs and treated with the pathogens Scrolotium rolfsii for pepper and Macrophomina phaseolina for mung bean and shrimp-based CNFs were used as a control. Treated plants had elevated levels of chitinase genes in response to CNFs at inoculation concentrations <10 mg/mL both in soil and media, to protect them against the pathogenic fungal disease. After 24 h of exposure to the pathogens, qRT-PCR showed genes class II chitinase gene (CaChi2) and polygalacturonase inhibitor protein 1 (PGIP1) to be up-regulated in both root and shoot at 0.1 and 1 mg/mL of inoculation, respectively. The ball milled mushroom CNFs were sufficient to trigger the membrane based enzymes with less diameter (≥15 nm) to be most efficient versus others. In vitro analysis showed IC50 of ball milled mushroom CNFs to be most efficient in limiting the growth of fungal biomass. Further trigger-like effects were prominent in reducing pathogenic fungal spread in both species.
Forest bug (red-legged shieldbug, Pentatoma rufipes) is a commonly occurring and widespread shiel... more Forest bug (red-legged shieldbug, Pentatoma rufipes) is a commonly occurring and widespread shieldbug species in the UK. It is particularly associated with woodland habitats and may remain in woodlands throughout the year, feeding on tree species such as oak, beech and hazel. However, forest bug also occurs in orchards and is emerging as an important pest of tree fruit in northern Europe. In recent years – particularly since the withdrawal of chlorpyrifos in 2016 – UK top-fruit agronomists have found increasing numbers of forest bugs in and around orchards. Their feeding activity on developing fruits is being linked with pitting and distortion damage to apples and pears. There has been limited scientific research into the ecology and control of this species, but some Belgian, Swiss and German studies provide valuable information on the timing of the life cycle and the effects of plant protection products. No information is available linking UK local population levels and activity wi...
This chapter reviews the transmission of plant viruses by aphids, with particular emphasis on the... more This chapter reviews the transmission of plant viruses by aphids, with particular emphasis on the virus-vector interactions, the attributes that make aphids such well-adapted vectors, the different modes of transmission, the determinants of transmissibility, the factors affecting virus acquisition and inoculation, control methods (e.g. use of virus-resistant or aphid-resistant genotypes, elimination of virus sources, and eradication of weeds, infected plants and volunteer plants), and prevention or reduction of virus spread by plant spacing and chemical, biological, cultural and integrated control of vectors among others.
... Virus acquisition must therefore be estimated by inoculation and subsequent symp-tom expressi... more ... Virus acquisition must therefore be estimated by inoculation and subsequent symp-tom expression. ... Want, JPH van der, 1954. Onderzoekingen over virusz-lekten van de boon (Phaseolus vulgaris L.). D. Phil. Thesis, Wageningen Agricultural University, The Netherlands. ...
The emergence of resistance mechanisms to, and revocation of, many insecticides used in the contr... more The emergence of resistance mechanisms to, and revocation of, many insecticides used in the control of the polyphagus aphid pest, Myzus persicae (Sulzer), has increased the pressure to develop novel approaches for the control of the pest in many crops. Kaolin-based particle films provide a physical barrier against insect pests and show considerable potential for controlling M. persicae. We conducted a series of laboratory experiments to investigate the mode of action of kaolin against aphids. The material appeared to have no direct effect on M. persicae; spraying adult aphids with aqueous kaolin suspension had no significant impact on their subsequent survival or reproduction on untreated plants. Similarly, when aphids were placed on kaolin-treated host-plants (Brassica oleracea), their performance (survival, growth rate and reproduction) was not significantly different from aphids on untreated plants. However, when M. persicae were given a choice between kaolin-treated and untreate...
The worldwide invasive insect pest, Drosophila suzukii Matsumura (spotted-wing Drosophila), lays ... more The worldwide invasive insect pest, Drosophila suzukii Matsumura (spotted-wing Drosophila), lays eggs in soft and stone fruit before harvest. Hatched larvae cause fruit collapse and significant economic losses. Current control methods rely primarily on foliar insecticide applications, which are not sustainable long-term solutions due to regulatory restrictions and the risk of insecticide resistance developing. We showed before that D. suzukii were deterred from laying eggs on artificial media previously visited by its sister species—Drosophila melanogaster. In the current study, laboratory choice test experiments were conducted to identify which D. melanogaster life stage (eggs, larvae, or adult) deterred D. suzukii oviposition. We demonstrated that the presence of live D. melanogaster larvae on the egg-laying media consistently deterred D. suzukii oviposition. Drosophila melanogaster cuticular hydrocarbons (CHCs) were examined as candidate for the oviposition deterrent. CHCs of lar...
ABSTRACTWoolly apple aphid (WAA, Eriosoma lanigerum Hausmann) (Hemiptera: Aphididae), is a major ... more ABSTRACTWoolly apple aphid (WAA, Eriosoma lanigerum Hausmann) (Hemiptera: Aphididae), is a major pest of apple trees (Malus domestica, order Rosales) and is critical to the economics of the apple industry in most parts of the world. Here, we generated a chromosome-level genome assembly of WAA – representing the first genome sequence from the aphid subfamily Eriosomatinae – using a combination of 10X Genomics linked-reads and in vivo Hi-C data. The final genome assembly is 327 Mb, with 91% of the assembled sequences anchored into six chromosomes. The contig and scaffold N50 values are 158 kb and 71 Mb, respectively, and we predicted a total of 28,186 protein-coding genes. The assembly is highly complete, including 97% of conserved arthropod single-copy orthologues based on BUSCO analysis. Phylogenomic analysis of WAA and nine previously published aphid genomes, spanning four aphid tribes and three subfamilies, reveals that the tribe Eriosomatini (represented by WAA) is recovered as a...
DL-β-aminobutyric acid (BABA) is a non-protein amino acid that is an effective inducer of resista... more DL-β-aminobutyric acid (BABA) is a non-protein amino acid that is an effective inducer of resistance against a variety of plant pathogens. However, examples of BABA-induced resistance against insect herbivores have not been reported. We applied BABA as a soil drench to legumes and monitored its effects on the pea aphid Acyrthosiphon pisum (Harris). On tic bean (Vicia faba var. minor), BABA increased aphid mortality, caused a reduction in the mean relative growth rate of individual insects and lessened the intrinsic rate of population increase (rm). BABA also caused significant reductions in the growth rate of A. pisum on pea (Pisum sativa), broad bean (Vicia faba var. major), runner bean (Phaseolus coccineus), red clover (Trifolium pratense) and alfalfa (Medicago sativa). No direct toxic effects of BABA against A. pisum were found, and no phytotoxic effects that may have caused a reduction in aphid performance were detected. Possible mechanisms behind this BABA-induced inhibition of...
ABSTRACT dl-β-Aminobutyric acid (BABA) is a nonprotein amino acid that can enhance defences in a ... more ABSTRACT dl-β-Aminobutyric acid (BABA) is a nonprotein amino acid that can enhance defences in a variety of plants against a wide range of pathogens. BABA can also reduce infestation by phytopathogenic nematodes and has recently been shown to suppress the growth of aphids feeding on legumes. This investigation examined the effect of applying BABA as a root drench to a range of Brassicaceae, including Arabidopsis thaliana, on the performance of two species of aphid (Myzus persicae and Brevicoryne brassicae) and the larvae of two species of Lepidoptera (Trichoplusia ni and Plutella xylostella). Application of BABA reduced the performance of all four insect species, and inhibition of insects occurred on all the plants tested. The results illustrate that BABA-induced resistance (BABA-IR) can affect generalist and specialist insect herbivores and inhibit insects feeding with mandibulate as well as sap-feeding mouthparts. The BABA-induced suppression of B. brassicae and P. xylostella feeding on A. thaliana provides a means to further examine the mechanisms of BABA-IR to insects using this model plant.
Increased industrial processes have introduced emerging toxic pollutants into the environment. Ph... more Increased industrial processes have introduced emerging toxic pollutants into the environment. Phytoremediation is considered to be a very useful, economical and ecofriendly way of controlling these pollutants, however, certain pollutants can potentially travel through the food chain and accumulate at hazardous levels. Four isomers of dinitrotoluenes (DNT) were investigated and observed their potential toxicity towards A. thaliana. Two different aphid species (generalist and specialist) were allowed to feed on plants treated with DNTs and toxicity to aphids determined. Reduced metabolites of DNT (in both plant and aphids) were recovered and quantified through GC-MS analyses. 2,6-DNT was observed to be the toxic of the DNTs tested. Complete metabolism of DNTs to their reduced products was never achieved for higher concentrations. Regioselectivity was observed in the case of 2,4-DNT, with 4A2NT as the dominant isomer. Feeding aphids showed a similar toxicity pattern for DNT isomers as...
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