Role of volatiles in arthropod vectors and plant disease interaction

Editor's Notes

1. In addition to simple compounds, such as oxygen, carbon dioxide, and water vapor,
2. herbivores, pollinators, and enemies of herbivores.
3. that include damage caused by herbivores and pathogens
4. Figure 1. Gas chromatograms of volatiles (desorbed from Porapak Q) emanating from ground elm wood infected with the fungal pathogen Ophiostoma novo-ulmi. Hewlett Packard 5890A gas chromatograph with DB-5 column (30 m!0.32 mm i.d.; J&W Scientific, Folsom, CA 95630) with flame ionization (FID) or electroantennographic detector (EAD: male or female Hylurgopinus rufipes antenna); splitless injection; temperature program: 50 8C (2 min), then 10 8C minK1 to 280 8C.
5. Summary of qualitative differences in volatile composition, as measured using headspace trapping and GC-MS analysis, between uninfected Arabis holboellii tissues (mostly fatty-acid-derived products), tissues infected with Puccinia monoica (dominated by aromatic compounds), and coblooming plants (rich in terpendoid volatiles). Chemical structures of representative compounds from each biochemical class are provided. (Complete data are given in Tables 1Ð4.)
6. however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Gram-negative, fastidious, phloem-limited bacterium
7. Figure 5. Chromatograms displaying volatile differences between Las-infected and non-infected plants. Release of methyl salicylate was significantly greater from plants infected with Las, while release of D-limonene and methyl anthranilate was significantly greater from noninfected plants Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants
8. Figure 1. Response of D. citri to odors emitted from Las infected versus non-infected citrus in a laboratory olfactometer.
9. Settling preference of combined non-infected and Las-infected D. citri on Las-infected versus non-infected citrus plants Panel (A) shows response under light conditions and panel (B) shows response under dark conditions. Experiments with Las infected and non-infected plants under complete darkness yielded similar results to those recorded under light.
10. C. picta, reared on uninfected plants without any contact with the phytoplasma during their ontogenesis (inexperienced), was attracted by the odor of infected plants (AP+; Fig. 1a; dependent paired t test, P<0.05). By contrast, C. picta that were reared on infected plants (experienced) showed the opposite behavior depending on their infection status when exposed to the different odor sources. The odor of infected apple was highly attractive for psyllids that had been infected by phytoplasma (P<0.001), while adults of C. picta that had not been infected were attracted by the odor of uninfected plants or repelled by the odor of infected plants, respectively (P<0.05).
11. were elevated by PLRV infection but not by PVX or PVY infection or sham inoculation compared with non-infected plants.
12. Mean±SEM proportional mV EAG responses by M. persicae to selected VOC elevated by PLRV infection (responses standardized to linalool=1 and control = paraffin oil)
13. Figure 1. (a) Location of M. persicae apterae after 1 h in dual choice tests comparing potato lea¯ ets from PLRV-infected plants with either uninfected plants (UNINF), PVY- or PVX-infected plants. Of the 100 aphids in each test, a mean of 59.7 responded (were located on one of the two treatments). Each pair of columns represents data from a single experiment.
14. 1. Arena used to conduct the headspace volatiles test. Aphids on screen above leaves were unable to contact leaf surfaces, and leaves remained attached to plants during bioassay.
15. Preferential response of R. padi apterae after 2 h in a dual choice test comparing BYDV-infected versus noninfected plants of the wheat varietyLambert, when aphids had contact with the leaves. Error bars are SEM of the total number of aphids on and near leaves responding to either treatment. Comparison was signiÞcant based on a generalized linear model, assuming a binomial distribution with a logit link function (P 0.0054).
16. FIGURE 2|Percentage of Tamarixia radiata responding to natural or synthetic odorants vs. blank or solvent negative controls, respectively, withina Y-tubeolfactometer. NR: Percentofnon-responders, n = 40. Asterisksindicatesignificantdifferencesbetweenthetwotreatments(∗∗P < 0.01, ∗∗∗P < 0.001).
17. FIGURE 3|Numberof Diaphorina citri nymphs parasitized by Tamarixia radiata on: Las-infected vs. uninfected plants (A)oron uninfected plants treated with a methylsalicylate(MeSA) lure vs. uninfected plants left untreated(B).
18. Exploitation of these host-specific microbe semiochemicals may provide important basis for future plant−insect−microbe chemical ecology investigations.