Fatty Acid-amino Acid Conjugates Diversification in Lepidopteran Caterpillars

Abstract

Fatty acid amino acid conjugates (FACs) have been found in noctuid as well as sphingid caterpillar oral secretions; in particular, volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants. These induced volatiles, in turn, attract natural enemies of the caterpillars. In a previous study, we showed that N-linolenoyl-L-glutamine in larval Spodoptera litura plays an important role in nitrogen assimilation which might be an explanation for caterpillars synthesizing FACs despite an increased risk of attracting natural enemies. However, the presence of FACs in lepidopteran species outside these families of agricultural interest is not well known. We conducted FAC screening of 29 lepidopteran species, and found them in 19 of these species. Thus, FACs are commonly synthesized through a broad range of lepidopteran caterpillars. Since all FAC-containing species had N-linolenoyl-L-glutamine and/or N-linoleoyl-L-glutamine in common, and the evolutionarily earliest species among them had only these two FACs, these glutamine conjugates might be the evolutionarily older FACs. Furthermore, some species had glutamic acid conjugates, and some had hydroxylated FACs. Comparing the diversity of FACs with lepidopteran phylogeny indicates that glutamic acid conjugates can be synthesized by relatively primitive species, while hydroxylation of fatty acids is limited mostly to larger and more developed macrolepidopteran species.

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

“…Plants may distinguish the type of attacking herbivore by the perception of herbivore-associated elicitors (3,19,32), but herbivores may also suppress plant responses by elicitors in their saliva (33,34). 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).…”

“…Salivary compounds may have evolved to allow herbivores to optimize nitrogen intake (35) or to suppress plant defense responses (33,34). In an evolutionary arms race, plants may have Fig.…”

Inducible De Novo Biosynthesis of Isoflavonoids in Soybean Leaves by Spodoptera litura Derived Elicitors: Tracer Techniques Aided by High Resolution LCMS

“…In addition, the amounts of [ Fig. 5B) (Mori et al 2003;Yoshinaga et al 2010). Based on the composition of FACs in gut contents, synthetic purified Nlinolenoyl-L-glutamine and N-linoleoyl-L-glutamine were used to evaluate eliciting activity in soybeans.…”

Nicotiana attenuata LECTIN RECEPTOR KINASE1 Suppresses the Insect-Mediated Inhibition of Induced Defense Responses during Manduca sexta Herbivory

“…FACs belong to a widely distributed family of HAEs present in the OS of a large number of lepidopteran species, including Manduca sexta (Yoshinaga et al, 2010), and they are necessary and sufficient to elicit herbivory-specific responses in several plant species including maize (Zea mays), soybean (Glycine max), eggplant (Solanum melongena), black nightshade (Solanum nigrum), and wild tobacco (Nicotiana attenuata; Alborn et al, 1997;Schmelz et al, 2009;VanDoorn et al, 2010;Bonaventure et al, 2011a). Some of the most abundant FACs are conjugates of Glu and Gln with unmodified or oxidized derivatives of polyunsaturated fatty acids (Alborn et al, 1997;Spiteller and Boland, 2003;VanDoorn et al, 2010;Yoshinaga et al, 2010).…”

“…Some of the most abundant FACs are conjugates of Glu and Gln with unmodified or oxidized derivatives of polyunsaturated fatty acids (Alborn et al, 1997;Spiteller and Boland, 2003;VanDoorn et al, 2010;Yoshinaga et al, 2010). Recently, it has been demonstrated that FACs are essential for the assimilation of nitrogen by developing larvae (Yoshinaga et al, 2008), making it impossible for the caterpillars to feed stealthily without eliciting a defense response by the plant.…”