Cucumber and Tomato Volatiles: Influence on Attraction in the Melon Fly<i>Zeugodacus cucurbitate</i>(Diptera: Tephritidae)

Njuguna, Peter K; Murungi, Lucy Kananu; Fombong, Ayuka T.; Teal, Peter E. A.; Beck, John J.; Torto, Baldwyn

doi:10.1021/acs.jafc.8b03452

Cited by 23 publications

(24 citation statements)

References 44 publications

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“… * Means with different letters for each compound are significantly different from each other (ANOVA followed by SNK post hoc test; P < 0.05, n = 3). DPI, days post infection; RI Calculated , retention index relative to C 8 –C 31 n -alkanes of an HP-5 MS column; RI Literature , retention index obtained from the literature; ND, not detected; BDL, below detection limit. ** Compound whose identity was established based on the comparison of retention time and mass spectra data with an authentic standard. *** Compound identified tentatively based on library data, calculated RI values, and comparison to the literature: (A), (B), (C), (D), (E), (F), (G), (H), and (I) …”

Section: Resultsmentioning

confidence: 99%

Compounds Associated with Infection by the Root-Knot Nematode, Meloidogyne javanica, Influence the Ability of Infective Juveniles to Recognize Host Plants

Kihika

Tchouassi

Ng’ang’a

et al. 2020

J. Agric. Food Chem.

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Plant root chemistry is altered by the parasitism of plant-parasitic nematodes (PPN). Here, we investigated the influence of the infective stage juveniles (J2) of Meloidogyne javanica in inducing tomato (Solanum lycopersicum) root volatiles and chemotactic effect on conspecifics. In olfactometer assays, J2 avoided the roots of 2-day infected plants but preferred 7-day-infected tomato compared to healthy plants. Chemical analysis showed a 2−7-fold increase in the amounts of monoterpenes emitted from tomato roots infected with M. javanica relative to healthy roots. In further bioassays, the monoterpenes β-pinene, (+)-( 2)-carene, αphellandrene, and β-phellandrene differentially attracted (51−87%) J2 relative to control. Concurrent reduction and increase in the levels of methyl salicylate and (Z)-methyl dihydrojasmonate, respectively, in the root volatiles reduced J2 responses. These results demonstrate that the host plant can alter its root volatile composition to inhibit PPN attack. The observed plant-produced inhibition of J2 warrants further investigation as a potential management tool for growers.

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Section: Resultsmentioning

confidence: 99%

Compounds Associated with Infection by the Root-Knot Nematode, Meloidogyne javanica, Influence the Ability of Infective Juveniles to Recognize Host Plants

Kihika

Tchouassi

Ng’ang’a

et al. 2020

J. Agric. Food Chem.

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“…Each compound detected in the headspace volatiles was quantified using the external calibration method. Due to unavailability of synthetic standard from each reported chemical class, a relative quantification was performed using the linear equation of a monoterpene to quantify compounds with a retention time of less than 16 min (range where monoterpenes are dominant in the headspace volatiles), and the linear equation of a sesquiterpene to quantify compounds with a retention time beyond 16 min, where sesquiterpenes are dominant in the headspace volatiles, and this followed the quantification method used by Njuguna et al 61 . The monoterpene α -pinene and the sesquiterpene α -humulene were run at different concentrations and the linear equations were generated from the calibration curves (Supplementary Fig.…”

Section: Methodsmentioning

confidence: 99%

Electroantennogram and machine learning reveal a volatile blend mediating avoidance behavior by Tuta absoluta females to a wild tomato plant

Miano

Ayelo

Musau

et al. 2022

Sci Rep

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Tomato cultivation is threatened by the infestation of the nocturnal invasive tomato pinworm, Tuta absoluta. This study was based on field observations that a wild tomato plant, Solanum lycopersicum var. cerasiforme, grown in the Mount Kenya region, Kenya, is less attacked by T. absoluta, unlike the cultivated tomato plants like S. lycopersicum (var. Rambo F1). We hypothesized that the wild tomato plant may be actively avoided by gravid T. absoluta females because of the emission of repellent allelochemical constituents. Therefore, we compared infestation levels by the pest in field monocrops and intercrops of the two tomato genotypes, characterized the headspace volatiles, then determined the compounds detectable by the insect through gas chromatography-linked electroantennography (GC-EAG), and finally performed bioassays using a blend of four EAG-active compounds unique to the wild tomato. We found significant reductions in infestation levels in the monocrop of the wild tomato, and intercrops of wild and cultivated tomato plants compared to the monocrop of the cultivated tomato plant. Quantitative and qualitative differences were noted between volatiles of the wild and cultivated tomato plants, and between day and night volatile collections. The most discriminating compounds between the volatile treatments varied with the variable selection or machine learning methods used. In GC-EAG recordings, 16 compounds including hexanal, (Z)-3-hexenol, α-pinene, β-myrcene, α-phellandrene, β-phellandrene, (E)-β-ocimene, terpinolene, limonene oxide, camphor, citronellal, methyl salicylate, (E)-β-caryophyllene, and others tentatively identified as 3,7,7-Trimethyl-1,3,5-cycloheptatriene, germacrene D and cis-carvenone oxide were detected by antennae of T. absoluta females. Among these EAG-active compounds, (Z)-3-hexenol, α-pinene, α-phellandrene, limonene oxide, camphor, citronellal, (E)-β-caryophyllene and β-phellandrene are in the top 5 discriminating compounds highlighted by the machine learning methods. A blend of (Z)-3-hexenol, camphor, citronellal and limonene oxide detected only in the wild tomato showed dose-dependent repellence to T. absoluta females in wind tunnel. This study provides some groundwork for exploiting the allelochemicals of the wild tomato in the development of novel integrated pest management approaches against T. absoluta.

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“…The response of an insect to a given compound is known to occur in dose-dependent manner ( Kihika et al, 2017 ; Njuguna et al, 2018 ). In this study, we showed that females of T. absoluta responded differently to the concentrations of the individual compounds and the blend with and without methyl salicylate against the control.…”

Section: Discussionmentioning

confidence: 99%

“…Three concentrations of each compound were tested in their natural release rate (ng/plant/h) from inoculated tomato plant, then by doubling and halving the amounts of each individual compound. Based on the results, three compounds (α-pinene, 2-carene, and β-phellandrene) were found attractive to females of T. absoluta and were tested in three-component blend at three concentrations against the control and methyl salicylate which was repellent to the females (2.17 ng/μL): (1.86 ng/μL α-pinene, 53.94 ng/μL 2-carene, 74.87 ng/μL β-phellandrene) (blend B1) which was subsequently doubled (blend B2) and diluted to one-half (blend B3) ( Njuguna et al, 2018 ; Kihika et al, 2020 ). In another set of experiment, methyl salicylate (2.17 ng/μL) was tested against non-inoculated tomato plant.…”

Section: Methodsmentioning

confidence: 99%

The Endophyte Trichoderma asperellum M2RT4 Induces the Systemic Release of Methyl Salicylate and (Z)-jasmone in Tomato Plant Affecting Host Location and Herbivory of Tuta absoluta

et al. 2022

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The use of endophytic fungi has dramatically increased plant performance through the enhancement of plant protection against abiotic and biotic stressors. We previously demonstrated that the endophytic fungus Trichoderma asperellum M2RT4 improves tomato defenses against the tomato leafminer Tuta absoluta through the reduction of oviposition, leafmining, pupation, and adult emergence. However, the underlying mechanism by which the presence of this endophytic fungus within tomato host plant affects T. absoluta host selection and life-history traits is unknown. We tested the behavioral responses of T. absoluta in Y-tube olfactometer bioassays and found that females preferred non-inoculated tomato plants against those inoculated by endophytes. Additionally, T. absoluta females were not attracted to non-inoculated infested nor to inoculated-infested tomato plants. Chemical analysis revealed the emission of methyl salicylate in inoculated tomato plant and an increase in the amounts of monoterpenes emitted from non-inoculated infested plants. Additionally, we found that upon herbivory, T. asperellum M2RT4 modulates tomato plant chemistry through the production of (Z)-jasmone thus activating both salicylic and jasmonic acid defense pathways. Further, T. absoluta females were attracted to monoterpernes including α-pinene, 2-carene, and β-phellandrene but repelled by methyl salicylate. Methyl salicylate could therefore be considered as a good semiochemical-based candidate for sustainable T. absoluta management using a “push-pull” approach. However, in dose-response bioassays, females of T. absoluta did not show any preference to the four component-blend (α-pinene, 2-carene, β-phellandrene, and methyl salicylate). (Z)-jasmone-treated tomato leaflets significantly reduced the leafmining activity of the pest at the concentration of 10 ng/μL and causing the highest larval mortality rate (83%) with the shortest LT50 (1.73 days) 7 days post-treatment. T. asperellum M2RT4 effect on herbivore performance was then (Z)-jasmone-mediated. These findings expand our understanding of how the endophytic fungus T. asperellum M2RT4 could mediate chemical interactions between T. absoluta and its host plant which are potentially important for development of environmentally friendly T. absoluta management programs.

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Cucumber and Tomato Volatiles: Influence on Attraction in the Melon FlyZeugodacus cucurbitate(Diptera: Tephritidae)

Cited by 23 publications

References 44 publications

Compounds Associated with Infection by the Root-Knot Nematode, Meloidogyne javanica, Influence the Ability of Infective Juveniles to Recognize Host Plants

Compounds Associated with Infection by the Root-Knot Nematode, Meloidogyne javanica, Influence the Ability of Infective Juveniles to Recognize Host Plants

Electroantennogram and machine learning reveal a volatile blend mediating avoidance behavior by Tuta absoluta females to a wild tomato plant

The Endophyte Trichoderma asperellum M2RT4 Induces the Systemic Release of Methyl Salicylate and (Z)-jasmone in Tomato Plant Affecting Host Location and Herbivory of Tuta absoluta

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