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Elife ; 102021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33875133


Insect herbivores use different cues to locate host plants. The importance of CO2 in this context is not well understood. We manipulated CO2 perception in western corn rootworm (WCR) larvae through RNAi and studied how CO2 perception impacts their interaction with their host plant. The expression of a carbon dioxide receptor, DvvGr2, is specifically required for dose-dependent larval responses to CO2. Silencing CO2 perception or scrubbing plant-associated CO2 has no effect on the ability of WCR larvae to locate host plants at short distances (<9 cm), but impairs host location at greater distances. WCR larvae preferentially orient and prefer plants that grow in well-fertilized soils compared to plants that grow in nutrient-poor soils, a behaviour that has direct consequences for larval growth and depends on the ability of the larvae to perceive root-emitted CO2. This study unravels how CO2 can mediate plant-herbivore interactions by serving as a distance-dependent host location cue.

Dióxido de Carbono/metabolismo , Herbivoria , Mariposas/fisiologia , Zea mays/metabolismo , Animais , Cadeia Alimentar , Larva/crescimento & desenvolvimento , Larva/fisiologia , Mariposas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo
Elife ; 82019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31509107


Herbivore natural enemies protect plants by regulating herbivore populations. Whether they can alter the behavior of their prey to increase predation success is unknown. We investigate if and how infection by the entomopathogenic nematode Heterorhabditis bacteriophora changes the behavior of healthy larvae of the western corn rootworm (Diabrotica virgifera), a major pest of maize. We found that nematode-infected rootworm cadavers are attractive to rootworm larvae, and that this behavior increases nematode reproductive success. Nematode-infected rootworms release distinct volatile bouquets, including the unusual volatile butylated hydroxytoluene (BHT). BHT alone attracts rootworms, and increases nematode reproductive success. A screen of different nematode and herbivore species shows that attraction of healthy hosts to nematode-infected cadavers is widespread and likely involves species-specific volatile cues. This study reveals a new facet of the biology of herbivore natural enemies that boosts their predation success by increasing the probability of host encounters.

Besouros/parasitologia , Herbivoria , Interações Hospedeiro-Parasita , Feromônios/metabolismo , Strongyloidea/crescimento & desenvolvimento , Strongyloidea/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Animais , Besouros/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/parasitologia , Zea mays/parasitologia
Elife ; 62017 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-29171835


Highly adapted herbivores can phenocopy two-component systems by stabilizing, sequestering and reactivating plant toxins. However, whether these traits protect herbivores against their enemies is poorly understood. We demonstrate that the western corn rootworm Diabrotica virgifera virgifera, the most damaging maize pest on the planet, specifically accumulates the root-derived benzoxazinoid glucosides HDMBOA-Glc and MBOA-Glc. MBOA-Glc is produced by D. virgifera through stabilization of the benzoxazinoid breakdown product MBOA by N-glycosylation. The larvae can hydrolyze HDMBOA-Glc, but not MBOA-Glc, to produce toxic MBOA upon predator attack. Accumulation of benzoxazinoids renders D. virgifera highly resistant to nematodes which inject and feed on entomopathogenic symbiotic bacteria. While HDMBOA-Glc and MBOA reduce the growth and infectivity of both the nematodes and the bacteria, MBOA-Glc repels infective juvenile nematodes. Our results illustrate how herbivores combine stabilized and reactivated plant toxins to defend themselves against a deadly symbiosis between the third and the fourth trophic level enemies.

Antibiose , Benzoxazinas/metabolismo , Besouros/fisiologia , Glucosídeos/metabolismo , Herbivoria/fisiologia , Toxinas Biológicas/metabolismo , Animais , Zea mays/parasitologia
Elife ; 52016 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-27352734


Endogenous jasmonates are important regulators of plant defenses. If and how they enable plants to maintain their reproductive output when facing community-level herbivory under natural conditions, however, remains unknown. We demonstrate that jasmonate-deficient Nicotiana attenuata plants suffer more damage by arthropod and vertebrate herbivores than jasmonate-producing plants in nature. However, only damage by vertebrate herbivores translates into a significant reduction in flower production. Vertebrate stem peeling has the strongest negative impact on plant flower production. Stems are defended by jasmonate-dependent nicotine, and the native cottontail rabbit Sylvilagus nuttallii avoids jasmonate-producing N. attenuata shoots because of their high levels of nicotine. Thus, endogenous jasmonates enable plants to resist different types of herbivores in nature, and jasmonate-dependent defenses are important for plants to maintain their reproductive potential when facing vertebrate herbivory. Ecological and evolutionary models on plant defense signaling should aim at integrating arthropod and vertebrate herbivory at the community level.

Ciclopentanos/metabolismo , Comportamento Alimentar/efeitos dos fármacos , Lagomorpha/fisiologia , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Tabaco/crescimento & desenvolvimento , Tabaco/metabolismo , Animais , Flores/crescimento & desenvolvimento , Herbivoria , Tabaco/genética