Disulfooxy fatty acids from the American bird grasshopper Schistocerca americana , elicitors of plant volatiles

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Since the first fatty acid amino acid conjugate (FAC) was isolated from regurgitant of Spodoptera exigua larvae in 1997 [volicitin: N-(17-hydroxylinolenoyl)-L-glutamine], their role as elicitors of induced responses in plants has been well documented. However, studies of the biosyntheses and the physiological role of FACs in the insect have been minimal. By using 14 C-labeled glutamine, glutamic acid, and linolenic acid in feeding studies of Spodoptera litura larvae, combined with tissue analyses, we found glutamine in the midgut cells to be a major source for biosynthesis of FACs. Furthermore, 20% of the glutamine moiety of FACs was derived from glutamic acid and ammonia through enzymatic reaction of glutamine synthetase (GS). To determine whether FACs improve GS productivity, we studied nitrogen assimilation efficiency of S. litura larvae fed on artificial diets containing 15 NH4Cl and glutamic acid. When the diet was enriched with linolenic acid, the nitrogen assimilation efficiency improved from 40% to >60%. In the lumen, the biosynthesized FACs are hydrolyzed to fatty acids and glutamine, which are reabsorbed into tissues and hemolymph. These results strongly suggested that FACs play an active role in nitrogen assimilation in Lepidoptera larva and that glutamine containing FACs in the gut lumen may function as a form of storage of glutamine, a key compound of nitrogen metabolism.volicitin ͉ insect physiology ͉ plant defense ͉ glutamine ͉ insect-produced elicitors

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Active role of fatty acid amino acid conjugates in nitrogen metabolism in Spodoptera litura larvae

Yoshinaga

Aboshi

Abe

et al. 2008

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“…The elicitors in saliva are often species-specific and diverse in structure (35,36). They range from plant cell wall fragments (37,38), peptides derived from ingested plant proteins (39), to fatty acid-amino acid conjugates (16,40), sulfur-containing fatty acids (41), and enzymes (15,42). In regurgitant of Pieris caterpillars, the enzyme β-glucosidase has been identified as playing a major role in eliciting plant responses after herbivory, including volatile emission (15).…”

Section: Discussionmentioning

confidence: 99%

Parasitoid-specific induction of plant responses to parasitized herbivores affects colonization by subsequent herbivores

Poelman

Zheng

Zhang

et al. 2011

109

Plants are exposed to a suite of herbivorous attackers that often arrive sequentially. Herbivory affects interactions between the host plants and subsequently attacking herbivores. Moreover, plants may respond to herbivory by emitting volatile organic compounds (VOCs) that attract carnivorous natural enemies of the herbivores. However, information borne by VOCs is ubiquitous and may attract carnivores, such as parasitoids, that differ in their effectiveness at releasing the plant from its herbivorous attackers. Furthermore, the development of parasitoids within their herbivorous hosts, attacking a given host plant, may influence the elicitation of defensive reactions in the host plant. This may, in turn, affect the behavior of subsequent herbivores attacking the host plant. Here, we show that the species identity of a parasitoid had a more significant effect on defense responses of Brassica oleracea plants than the species identity of the herbivorous hosts of the parasitoids. Consequently, B. oleracea plants that were damaged by caterpillars (Pieris spp.) parasitized by different parasitoid species varied in the degree to which diamondback moths (Plutella xylostella) selected the plants for oviposition. Attracting parasitoids in general benefitted the plants by reducing diamondback moth colonization. However, the species of parasitoid that parasitized the herbivore significantly affected the magnitude of this benefit by its species-specific effect on herbivore-plant interactions mediated by caterpillar regurgitant. Our findings show that information-mediated indirect defense may lead to unpredictable consequences for plants when considering trait-mediated effects of parasitized caterpillars on the host plant and their consequences because of community-wide responses to induced plants.herbivore preference | induced gene transcription | parasitoid-dependent effect A cross their whole kingdom, plants have been found to interact with carnivorous arthropods that act to control herbivorous attackers of the plants. Such interactions between plants and carnivorous arthropods may ultimately increase fitness of the plants (1-3). Plant traits involved in such interactions include those that provide a predator/parasitoid with a resource such as, for example, food or shelter, or with information on the presence and abundance of herbivorous prey/hosts (4, 5). Although resource-and information-mediated indirect defenses of plants have long been collectively viewed within the context of ecological and evolutionary theory of indirect defenses, interactions between plants and carnivorous arthropods based on resource provisioning are distinctly different from those mediated by providing information (6). Whereas resource provisioning can be obligate and is often restricted to interactions with a limited number of carnivorous species, information emitted by herbivore-infested plants is generally ubiquitous, allowing all other organisms to respond to this information (5). Release of herbivore-induced volatile organic compounds (VOCs)...

“…The chemical nature of a few elicitors of feeding-induced plant defense responses are known: fatty acid-amino acid conjugates, including volicitin, of several lepidopterans (6,7,(23)(24)(25)(26); peptides derived by proteolysis from chloroplastic ATP synthase of herbivore-damaged plants (27,28); disulfo-oxy fatty acids of grasshopper regurgitant, named caeliferins (29); and the enzyme ␤-glucosidase from Pieris brassicae oral secretions (8). Application of these elicitors onto plant wounds results in the release of volatiles that repel ovipositing herbivores (30) or attract natural enemies of herbivores (31).…”

Section: Discussionmentioning

confidence: 99%

Male-derived butterfly anti-aphrodisiac mediates induced indirect plant defense

Fatouros¹,

Broekgaarden

Bukovinszkine’Kiss³

et al. 2008

112

106

Plants can recruit parasitic wasps in response to egg deposition by herbivorous insects-a sophisticated indirect plant defense mechanism. Oviposition by the Large Cabbage White butterfly Pieris brassicae on Brussels sprout plants induces phytochemical changes that arrest the egg parasitoid Trichogramma brassicae. Here, we report the identification of an elicitor of such an ovipositioninduced plant response. Eliciting activity was present in accessory gland secretions released by mated female butterflies during egg deposition. In contrast, gland secretions from virgin female butterflies were inactive. In the male ejaculate, P. brassicae females receive the anti-aphrodisiac benzyl cyanide (BC) that reduces the females' attractiveness for subsequent mating. We detected this pheromone in the accessory gland secretion released by mated female butterflies. When applied onto leaves, BC alone induced phytochemical changes that arrested females of the egg parasitoid. Microarray analyses revealed a similarity in induced plant responses that may explain the arrest of T. brassicae to egg-laden and BC-treated plants. Thus, a male-derived compound endangers the offspring of the butterfly by inducing plant defense. Recently, BC was shown to play a role in foraging behavior of T. brassicae, by acting as a cue to facilitate phoretic transport by mated female butterflies to oviposition sites. Our results suggest that the antiaphrodisiac pheromone incurs fitness costs for the butterfly by both mediating phoretic behavior and inducing plant defense.egg parasitoid ͉ elicitor ͉ Trichogramma brassicae ͉ Pieris brassicae ͉ Brussels sprouts C hemical signals play a crucial role in the interactions between herbivorous insects and parasitic wasps (1). To locate the tiny eggs of herbivorous host insects in an 'ocean' of plant biomass, egg parasitoids have been shown to employ chemical cues either induced in the plant by host egg deposition or from the adult host stage [i.e., infochemical detour, (2)], whereas only short-range cues emanate from the eggs themselves (3). Plants injured by feeding herbivores often start to release chemical cues that attract predators and parasitoids to effectively defend the plant by killing the herbivores (4, 5). This indirect plant defense may be triggered by compounds in the regurgitant of the herbivore, allowing the plant to discriminate between mechanical wounding and insect feeding (6-8). Plants can also respond before being damaged by insect feeding. Egg deposition by herbivorous insects induces volatiles attractive to egg parasitoids in tritrophic interactions associated with elm, pine, and bean plants (9). The elicitor of these oviposition-induced parasitoid attractants (synomones) was shown to be located in the oviduct secretion of the female herbivore, which is used to glue eggs onto leaves (10,11).Recent data revealed that egg deposition by Pieris brassicae on Brussels sprouts plants (Brassica oleracea var. gemmifera cv. Cyrus) induces chemical changes in the leaf surface that arrest the egg parasi...