Project description:Predatory bugs capture prey by injecting venom from their salivary glands using specialized stylets. Understanding venom function has been impeded by a scarcity of knowledge of their venom composition. We therefore examined the proteinaceous components of the salivary venom of the predatory stink bug Arma chinensis (Hemiptera: Pentatomidae). Using gland extracts and venoms from 5th-instar nymphs or adult females, we performed shotgun proteomics combined with venom gland transcriptomics. We found that the venom of A. chinensis comprised a complex suite of over a hundred individual proteins, including oxidoreductases, transferases, hydrolases, ligases, protease inhibitors, and recognition, transport and binding proteins. Besides the uncharacterized proteins, hydrolases such as venom serine proteases, cathepsins, phospholipase A2, phosphatases, nucleases, alpha-amylases, and chitinases constitute the most abundant protein families. However, salivary proteins shared by and unique to other predatory heteropterans were not detected in A. chinensis venom. Injection of the proteinaceous (> 3 kDa) venom fraction of A. chinensis gland extracts or venom into its prey, the larvae of the Oriental armyworm Mythimna separata (Walker, 1865), revealed insecticidal activity against lepidopterans. Our data expands the knowledge of heteropteran salivary proteins and suggests predatory asopine bugs as a novel source for bioinsecticides.
Project description:Assassin bugs (Hemiptera: Heteroptera: Reduviidae) are venomous insects that prey on invertebrates. Assassin bug venom has features in common with venoms from other animals, such as paralysing and lethal activity when injected, and a molecular composition that includes disulfide-rich peptide neurotoxins. Uniquely, this venom also has strong liquefying activity that has been hypothesised to facilitate feeding through the narrow channel of the proboscis—a structure inherited from sap- and phloem-feeding phytophagous hemipterans and adapted during the evolution of Heteroptera into a fang and feeding structure. However, further understanding of the function of assassin bug venom is impeded by the lack of proteomic studies detailing its molecular composition. In addition, the lack of knowledge regarding venoms of predaceous reduviids limits our understanding of how the venoms of the blood-feeding kissing bugs (Reduviidae: Triatominae) evolved to facilitate hematophagy. By using a combined transcriptomic/proteomic approach we show that the venom proteome of the harpactorine assassin bug Pristhesancus plagipennis includes a complex suite of >100 proteins comprising disulfide-rich peptides, CUB-domain proteins, cystatins, putative cytolytic toxins, triabin-like protein, odorant binding protein, serine proteases, catabolic enzymes, putative nutrient-binding proteins, plus eight families of proteins without homology to characterised proteins. Serine proteases, CUB domain proteins and other novel proteins in the 10–16 kDa mass range, as well as putative cytolytic toxins, were the most abundant venom components. Thus, in addition to putative neurotoxins, assassin bug venom includes a high proportion of enzymatic and cytolytic venom components well suited to tissue liquefaction. While some protein families such as lipocalin/triabins occur in the venoms of both predaceous and blood-feeding reduviids, the composition of venoms in these two groups differs markedly. These results provide insights into the venom evolution in the insect suborder Heteroptera.
Project description:The invasive Halyomorpha halys Stål, the Brown Marmorated Stink Bug (BMSB), and the native Nezara viridula L., the Southern Green Stink Bugs (SGSB), are widely distributed in Europe, even if the date of introduction and their diet differ. Saliva of Hemipteran pests plays an essential role in the interaction between insects and their host plants. Several aphid salivary proteomes have been identified and found to differ according to the species, while no comparative investigation between phytophagous stink bugs has been performed yet. Here we analyzed the salivary proteins from two bugs, BMSB and SGSB, using LC-MS/MS. A total of 238 and 305 proteins were identified from dissected salivary glands from BMSB and SGSB respectively. Among these, a large majority was found in both species. In comparison with salivary proteome from other Hemiptera, the most striking feature of the salivary gland proteomes from SGSB and BMSB is the similar protein functions patterns. Some of the proteins are speculated to be dependent of the feeding strategies, playing a significant role in plant-insect interactions. Our results provide a framework for future research to elucidate the molecular basis of differential impact of piercing-sucking insects on host plants.
Project description:The invasive Halyomorpha halys Stål, the Brown Marmorated Stink Bug (BMSB), and the native Nezara viridula L., the Southern Green Stink Bugs (SGSB), are widely distributed in Europe, even if the date of introduction and their diet differ. Saliva of Hemipteran pests plays an essential role in the interaction between insects and their host plants. Several aphid salivary proteomes have been identified and found to differ according to the species, while no comparative investigation between phytophagous stink bugs has been performed yet. Here we analyzed the salivary proteins from two bugs, BMSB and SGSB, using LC-MS/MS. A total of 238 and 305 proteins were identified from dissected salivary glands from BMSB and SGSB respectively. Among these, a large majority was found in both species. In comparison with salivary proteome from other Hemiptera, the most striking feature of the salivary gland proteomes from SGSB and BMSB is the similar protein functions patterns. Some of the proteins are speculated to be dependent of the feeding strategies, playing a significant role in plant-insect interactions. Our results provide a framework for future research to elucidate the molecular basis of differential impact of piercing-sucking insects on host plants.
Project description:Transcriptomic data was obtained from adults of the stink bug Nezara viridula to complement biochemical enzymatic activity analysis performed for digestive enzymes. Pooled reads from all sample types were used for de novo assembly of a reference transcriptome. After mapping reads to reference, differential expression was performed between the different tissues of the same diet or between the same tissue in different diets.