Multiple stress factors and the emission of plant VOCs

Previous studies have shown that vector-borne pathogens can alter the phenotypes of their hosts and vectors in ways that influence the frequency and nature of interactions between them, with significant implications for the transmission and spread of disease. For insect-borne pathogens, host odors are particularly likely targets for manipulation, because both plant- and animal-feeding insects use volatile compounds derived from their hosts as key foraging cues. Here, we document the effects of a widespread plant pathogen, Cucumber mosaic virus (CMV), on the quality and attractiveness of one of its host plants (Cucurbita pepo cv. Dixie) for two aphid vectors, Myzus persicae and Aphis gossypii. Our results indicate that CMV greatly reduces host-plant quality—aphids performed poorly on infected plants and rapidly emigrated from them—but increases the attractiveness of infected plants to aphids by inducing elevated emissions of a plant volatile blend otherwise similar to that emitted by healthy plants. Thus, CMV appears to attract vectors deceptively to infected plants from which they then disperse rapidly, a pattern highly conducive to the nonpersistent transmission mechanism employed by CMV and very different from the pattern previously reported for persistently transmitted viruses that require sustained aphid feeding for transmission. In addition to providing a documented example of a pathogen inducing a deceptive signal of host-plant quality to vectors, our results suggest that the transmission mechanism is a major factor shaping pathogen-induced changes in host-plant phenotypes. Furthermore, our findings yield a general hypothesis that, when vector-borne plant or animal pathogens reduce host quality for vectors, pathogen-induced changes in host phenotypes that enhance vector attraction frequently will involve the exaggeration of existing host-location cues.

https://www.pnas.org/content/pnas/107/8/3600.full.pdf

Deceptive chemical signals induced by a plant virus attract insect vectors to inferior hosts

Behavioural aspects influencing plant virus transmission by homopteran insects.

Oxylipins: structurally diverse metabolites from fatty acid oxidation.

Begomoviruses (Family Geminiviridae, Genus Begomovirus) have become the most destructive group of plant viruses in tropical and subtropical regions of the world. The recent emergence of begomoviruses is notable, as these viruses have been co-evolving with their dicotyledonous plant hosts for millennia. Agricultural intensification has been proposed as one of the main causes, together with increases in populations of their vector Bemisia tabaci, partly due to the worldwide spread of the more fecund B-biotype. Reports of new diseases and associated epidemics are frequent. Many such reports describe the evolution of more aggressive virus variants through recombination. Little is known about the selection pressures that seem to operate and drive begomovirus evolution towards increased virulence and an extended host range. It is apparent, however, that the genomes of begomoviruses show extreme plasticity leading to an ability to evolve very rapidly in response to changing cropping systems. Genetic diversity is...

Factors Influencing Begomovirus Evolution and Their Increasing Global Significance: Implications for Sustainable Control

The influence of viral disease symptoms on the behaviour of virus vectors has implications for disease epidemiology. Here we show that previously reported preferential colonization of potatoes infected by potato leafroll virus (genus Polerovirus) (luteovirus) (PLRV) by alatae of Myzus persicae, the principal aphid vector of PLRV, is influenced by volatile emissions from PLRV-infected plants. First, in our bioassays both differential immigration and emigration were involved in preferential colonization by aphids of PLRV-infected plants. Second, M. persicae apterae aggregated preferentially, on screening above leaflets of PLRV-infected potatoes as compared with leaflets from uninfected plants, or from plants infected with potato virus X (PVX) or potato virus Y (PVY). Third, the aphids aggregated preferentially on screening over leaflet models treated with volatiles collected from PLRV-infected plants as compared with those collected from uninfected plants. The specific cues eliciting the aphid responses were not determined, but differences between headspace volatiles of infected and uninfected plants suggest possible ones.

http://europepmc.org/articles/PMC1690919?pdf=render

Volatiles from potato plants infected with potato leafroll virus attract and arrest the virus vector, Myzus persicae (Homoptera: Aphididae)

Simultaneous detection of potato viruses, PLRV, PVA, PVX and PVY from dormant potato tubers by TaqMan® real-time RT-PCR

Potyvirus Isolation and RNA Extraction

Correction for ‘Volatiles from potato plants infected with potato leafroll virus attract and arrest the virus vector, Myzus persicae (Homoptera: Aphididae)’ by S. D. Eigenbrode, H. Ding, P. Shiel and P. H. Berger (Proc. R. Soc. Lond. B 269 , 455–460.
 (doi: 10.1098/rspb.2001.1909)). On page 458, in §3e, and on page 459, in table 2, the compound listed as ‘cobebene’ should be listed as ‘cubebene’. On page 459, in table 2 and in paragraph 3 of §4, the compound listed as ‘7-11-dimethyl-3-methyl-dodecatriene’ should be listed as ‘7,11 dimethyl-3-methylene dodecatriene’ or ‘β-farnesene’.

Correction for Eigenbrode et al., Volatiles from potato plants infected with potato leafroll virus attract and arrest the virus vector, Myzus persicae (Homoptera: Aphididae)

Patrick J. Shiel

Papers

Volatiles from potato plants infected with potato leafroll virus attract and arrest the virus vector, Myzus persicae (Homoptera: Aphididae)

Simultaneous detection of potato viruses, PLRV, PVA, PVX and PVY from dormant potato tubers by TaqMan® real-time RT-PCR

Potyvirus Isolation and RNA Extraction

Correction for Eigenbrode et al., Volatiles from potato plants infected with potato leafroll virus attract and arrest the virus vector, Myzus persicae (Homoptera: Aphididae)