Evidence of the Involvement of a Plus-C Odorant-Binding Protein HparOBP14 in Host Plant Selection and Oviposition of the Scarab Beetle Holotrichia parallela

Abstract

Holotrichia parallela is one of the agriculturally important scarab beetle pests in China. In this study, HparOBP14 was cloned, which is the most abundantly expressed among the OBP genes in the legs of female H. parallela adults. Sequence comparison and phylogenetic analysis showed that HparOBP14 has a Plus-C structure motif. The expression profile analysis revealed that HparOBP14 expression was the highest in the female antennae and then in the legs. The fluorescence competitive binding experiment of the recombinant HparOBP14 protein showed that HparOBP14 had an affinity with 6-methyl-5-heptene-2-one (plant volatile), 3-methylindole, p-cymene, methanol, formaldehyde, α-pinene, and geraniol (organic fertilizer volatile). Knockdown HparOBP14 expression decreased significantly the EAG response of the injected female adults to p-cymene, methanol, formaldehyde, α-pinene, and geraniol. Similarly, the injected female adults were significantly less attracted to geraniol and methanol. Therefore, HparOBP14 might bind organic matter volatiles during oviposition. These results are not only helpful to analyze the olfactory recognition mechanism of female adult H. parallela when choosing suitable oviposition sites, but also to provide target genes for green prevention and control of H. parallela in the future.

PI3K/Akt/CncC signaling pathway mediates the response to EPN‐Bt infection in Holotrichia parallela larvae

“…Adults of H. parallela were collected from Shijiazhuang, Hebei Province, China. These insects were reared on fresh elm leaves in a plastic box under laboratory conditions at 25 °C with a 12/12 h light/dark photoperiod and 70% relative humidity (RH) (Ningbo, China) 37 . The eggs were incubated at 18% soil moisture (w/w).…”

“…These insects were reared on fresh elm leaves in a plastic box under laboratory conditions at 25 °C with a 12/12 h light/dark photoperiod and 70% relative humidity (RH) (Ningbo, China). 37 The eggs were incubated at 18% soil moisture (w/w). The larvae of H. parallela were fed potatoes and kept individually in the holes of six-well bioassay trays (Corning Inc., NY, USA) filled with 15 g and 18% soil moisture of high-temperature sterilized sandy loam soil.…”

Implication of antioxidant and detoxifying enzymes in the resistance of Holotrichia parallela larvae to EPN-Bt infection

“…Adults of H. parallela were collected from Shijiazhuang, Hebei Province, China. These insects were reared on fresh elm leaves in a plastic box under laboratory conditions at 25°C with a 12/12 h light/dark cycle and 70% relative humidity (RH) (Qu et al 2021). The eggs were incubated at 18% soil moisture (w/w).…”

Host plant recognition by two odorant‐binding proteins in Rhynchophorus ferrugineus (Coleoptera: Curculionidae)

“…Studies on ApisOBP3 of Acyrthosiphon pisum , 7 AgamOBP1 of Anopheles gambiae , 8 and BdorOBP83a‐2 of Bactrocera dorsalis 9 suggested that OBPs can specifically recognize and screen specific chemical signals; thus, more is at play than just passive transport. Previous studies have shown that OBPs could participate in the recognition of a variety of external odorant cues, including sex pheromones, alarm pheromones, oviposition attractants, host plant volatiles, and so forth 10–13 . In Drosophila melanogaster , mutants of OBP76a ( lush ) show abnormal behavioral responses to alcohols and the male sex pheromone cis ‐vaccenyl acetate (cVA) 14,15 .…”

“…Previous studies have shown that OBPs could participate in the recognition of a variety of external odorant cues, including sex pheromones, alarm pheromones, oviposition attractants, host plant volatiles, and so forth. [10][11][12][13] In Drosophila melanogaster, mutants of OBP76a (lush) show abnormal behavioral responses to alcohols and the male sex pheromone cis-vaccenyl acetate (cVA). 14,15 Both OBP57d and OBP57e in Drosophila melanogaster and Drosophila sechellia are involved in recognizing their respective hosts; when OBP57d and OBP57e of Drosophila sechellia were transferred to Drosophila melanogaster, Drosophila melanogaster preferably oviposited into the host plant of Drosophila sechellia.…”