Bemisia tabaci is a polyphagous pest that transmits various viruses, including tomato yellow leaf curl virus (TYLCV) while feeding on crops. Prior to identifying attractants of B. tabaci, the pheromone biosynthesis activating neuropeptide (PBAN) sequence was obtained via transcriptome analysis of female adults. After injecting artificially synthesized PBAN into the female adults, the compounds contained in the female adults were extracted using hexane, and gas chromatography-mass spectrometry (GC-MS) was performed. As a result, 22 compounds showed quantitative differences after PBAN injection. Among them, it was confirmed that B. tabaci is attracted to 2-ethylhexanoic acid and phytol. These results suggest that 2-ethylhexanoic acid and phytol can be used as attractants for the control of B. tabaci.

신경펩타이드(Neuropeptide)는 신경세포에서 분비되는 단백질성 물질로, 곤충 호르몬에서 가장 큰 그룹으로 차지한다. 이들은 곤충의 전 생육단계에 걸쳐 지방체의 항상성, 섭식, 소화, 배설, 순환, 번식, 탈피/변태 등 다양한 생리적 기능과 행동을 조절하는데 관여하고 있다. 신경호 르몬 일종인 PRXamide (NH2) 펩타이드 계열 호르몬은 카르복실기 끝에 PRX (X, 다양한 아미노산)라는 공통의 아미노산 서열이 특징적으로 존재하고 있으며, 곤충 전반에 걸쳐 발견된다. 곤충에서PRX 신경호르몬은 다양한 생물학적 기능에 관련하고 있는데 호르몬구조와 기능에 따라 크게 3가지로 분류한다. Pyrokinin (PK)계열의 호르몬은 페로몬 생합성 활성화 신경펩타이드(pheromone biosynthesis activating neuropeptide, PBAN) 및 휴면 호르몬(diapause hormone, DH)이 속하며, 카파(CAPA) 펩타이드 호르몬, 그리고 탈피촉진 호르몬(ecdysis trigging hormone, ETH)이 여기에 속한다. PK 계열의 PBAN 호르몬은 지금으로부터 약 30년전 나방에서 처음 밝혀졌으며, 성페로몬 생합성 을 자극하는 신경호르몬으로 확인되었다. 그 이후, PBAN의 연구는 절지동물 전반에 걸쳐 다양한 연구자들에 의하여 광범위하게 이루어졌다. 본 종설은 PBAN의 유전자 구조와 발현, PBAN에 의한 세포신호 전달과 성페로몬 생합성에 관련된 생리적 기작, 그리고 신경호르몬과 PBAN을 이용한 새로운 해충 방제법 개발의 가능성과 예를 소개한다.

나방류의 페로몬 생합성은 식도아래 신경절에서 생산된 페로몬 생합성 촉진 신경펩타이드(pheromone biosynthesis activating neuropeptide, PBAN)의 분비로부터 시작된다. 분비된 PBAN은 페로몬샘의 상피세포막에 있는 PBAN 수용체와 결합하고, 신호전달과정을 거쳐 페 로몬 생합성과정이 활성화되어, 페로몬이 외부로 방출된다. 본 종설은 콩명나방(Maruca vitrata)의 성페로몬, PBAN과 수용체, 성페로몬 생합성 경로를 소개한다.

In moth, pheromone biosynthesis activating neuropeptide (PBAN) regulates pheromone biosynthesis by binding to its receptor (PBANr). In this study, we cloned a PBANr gene (Mvi-PBANr) from sex pheromone gland in M. vitrata, which encodes 475 amino acid and includes 7 transmembrane domains. As a results of phylogenetic analysis, Mvi-PBANr is clustered with lepidopteran PBANrs. Mvi-PBANr was investigated for the effect of pheromone biosynthesis via RNA interference (RNAi), gas chromatography (GC) and bioassay. Consequently, expression level of Mvi-PBANr suppressed via RNAi, resulting in decrease pheromone component (E10E12-16:Ald). Mating rate was also reduced when performing the RNAi. These results revealed that Mvi-PBANr played important role in the pheromone biosynthesis in M. vitrata, and Mvi-PBANr can be used as new pest control targets.

The pheromone biosynthesis in Plutella xylostella is more active in the scotophase than in the photophase, indicating that there may be changes of gene expression in the pheromone glands. To identify genes contributing to change in pheromone production, we analyzed transcriptomes of pheromone glands from both decapitated females (PG-minus) in the photophase and normal ones (PG-plus) in the scotophase. Deep sequencing for mRNAs in the pheromone gland yielded approximately 7.5Gb and 6,671 transcripts showing positive FPKM value were analyzed. Differentially expressed gene analysis revealed that up- and down-regulated transcripts were 310 and 326 in the PG-plus transcriptome, respectively. Genes putatively involved in the pheromone biosynthesis pathway were identified such as acetyl-CoA carboxylase, acetyl-CoA dehydrogenase, fatty acid synthase (FAS), desaturases (Δ9 and Δ 11) and fatty acid reductases of pheromone gland (pgFAR), alcohol oxidase, aldehyde oxidase and aldehyde reductase, etc. Quantitative RT-PCR revealed that expressions of FAS, Δ11 desaturase and pgFAR were significantly higher in PG-plus, suggesting that they may have crucial roles in sex pheromone biosynthesis of P. xylostella

Pheromone biosynthesis activating neuropeptide (PBAN) produced in the suboesophageal ganglion stimulates pheromone biosynthesis in the pheromone gland, mediating sexual behaviors. Based on the transcriptome of the head, PBAN in the legume pod borer, Maruca vitrata, was identified. To examine the pheromonotropic activity of PBAN in the legume pod borer, Maruca vitrata, a PBAN (Mvi-PBAN) was synthesized. When female adults were injected with a synthetic Mvi-PBAN, pheromone production showed a maximal increase 2 h post-injection. PBAN was expressed in all examined tissues and developmental stages. In contrast, PBAN receptor (PBANr) was detected in the female tissues and all developmental stages except for adult male. In addition, two types of PBANr were identified from the transcriptome of the pheromone gland, suggesting that the molecular signal on the pheromone gland may transduce via PBANr.

Pheromone biosynthesis in the pheromone gland is stimulated by pheromone biosynthesis activating neuropeptide (PBAN) produced in the suboesophageal ganglion. PBAN binds its receptor and transduces biological signal into the molecules for the pheromone biosynthesis. To understand pheromone biosynthesis pathway in legume pod borer, Maruca vitrata, transcriptome of the pheromone gland was analyzed. A total of 191 contigs involved in the pheromone biosynthesis were identified. Putative pheromone biosynthetic pathways for sex pheromone components in M. vitrata were proposed through transcriptomic analysis.

Pheromone biosynthesis activating neuropeptide (PBAN) produced in the subesophageal ganglion is known to stimulate pheromone production in the pheromone gland. A cDNA isolated from female adult heads of Maruca vitrata encodes 197 amino acids including PBAN, designated as Mvi-PBAN, and four other neuropeptides (NPs): diapause hormone (DH) homologue, α-NP, β-NP and γ-NP. All of the peptides are amidated in their C-termini and shared a conserved motif, FXPR(or K)L-NH2 structure. Mvi-PBAN consists of 35 amino acids as previously reported (Chang and Ramasamy, 2014). RT-PCR analysis revealed that Mvi-PBAN cDNA was expressed in all examined body parts. Nucleotide sequence analysis of RT-PCR products indicated the Mvi-PBAN sequence was identical in all examined body parts of both sexes. These results suggest that Mvi-PBAN expression is maintained in examined stages or tissues.

Pheromone biosynthesis-activating neuropeptide (PBAN), produced in subesophageal ganglion, is known to stimulate pheromone biosynthesis in Plutella xylostella. The pheromone production is more active in the scotophase than in the photophase, which suggests that there may be changes of gene expression in the pheromone glands. To analyze gene expression involving in pheromone biosynthesis for 24 hrs, we performed transcriptomes of pheromone glands which were isolated at every 4 h. Eleven pheromone biosynthesis-related genes, acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), acyl-CoA dehydrogenase, enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, Δ9 desaturase, Δ11 desaturase, fatty acid reductase (FAR), alcohol oxidase, aldehyde oxidase, and aldehyde reductase were identified. Among these genes, ACC, FAS and chain shortening enzymes involving in early stage of pheromone biosynthesis exhibited their highest expression between AM9 and PM5. Desaturases, Δ9 and Δ11, showed the peak of expression at PM1 and AM5 or PM5, respectively. Interestingly, FAR expression was the highest at AM1, active reproductive period. These results suggest that genes involving in pheromone biosynthesis can be sequentially regulated for their biological roles.

The pheromone biosynthesis in Plutella xylostella is stimulated a neuropeptide, pheromone biosynthesis activating neuropeptide which is produced in subesophageal ganglion. The pheromone production is more active in the scotophase than in the photophase, which suggests that there may be changes of gene expression in the pheromone glands. To analyze gene expression related to pheromone biosynthesis, we performed transcriptomes of pheromone glands which were isolated at every 4 h. Eleven pheromone biosynthesis-related genes, acetyl-CoA carboxylase, fatty acid synthase, acyl-CoA dehydrogenase, enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, Δ9 desaturase, Δ11 desaturase, fatty acid reductase, alcohol oxidase, aldehyde oxidase, and aldehyde reductase were identified. Among these genes, the expression of aldehyde reductase and aldehyde oxidase were relatively higher in the scotophase than in photophase, which may affect increase of pheromone production in the scotophase. Expression of signal genes involving in pheromone biosynthesis such as acyl-CoA desaturase, FAR, PBAN receptor, fatty acid transporter and acyl-CoA binding protein did not exhibited any significant difference.

The oriental fruit moth (Grapholita molesta) and the plum fruit moth (G. dimorpha) are internal feeders of apples. Their sympatric and similar sex pheromone compositions suggest their recent divergence in speciation. This study aims to determine genetic factors in this speciation by comparing transcriptomes associated in sex pheromone biosynthesis in these sibling species. Total RNAs were collected two female abodominal tips and read by a short read deep sequencing technology using an lllumina HiSeq. Almost 3-4 Gb reads were de novo assembled and resulted in 76,361 contigs of G. dimorpha and 104,463 contigs of G. molesta. More than 70% of these contigs were annotated and classified by a typical GO analysis. Transcriptomes related with sex pheromone biosynthesis were selected and grouped into fatty acid synthase, fatty acid oxidation. These analyses identified sex pheromone biosynthesis machineries

Sex pheromone production is regulated by pheromone biosynthesis-activating neuropeptide (PBAN) in many lepidopteran species. A cDNA isolated from female adult heads of Plutella xylostella encodes 193 amino acids including PBAN, designated as Plx-PBAN. When female adults were injected with synthetic Plx-PBAN, pheromone production showed a maximal increase 1h post-injection. RT-PCR screening revealed that Plx-PBAN cDNA was expressed in all examined body parts, with the highest expression level in the head of female adults. The PBAN receptor (Plx-PBANr) gene was also cloned from the female pheromone gland and has conserved structural motifs implicating in promoting G protein coupling and tyrosine-based sorting signaling along with seven transmembrane domains. The expression of Plx-PBANr was found only in the pheromone gland of female adults among examined tissues and developmental stages. Heterologous expression in human uterus cervical cancer cells revealed that Plx-PBANr induced significant calcium elevation when challenged with Plx-PBAN. Female P. xylostella injected with double-stranded RNA specific to Plx-PBANr showed suppression of the receptor gene expression and exhibited significant reduction in pheromone biosynthesis, which resulted in loss of male attractiveness. In addition, to assess molecular events occurring downstream of PBAN signaling, partial sequences of Δ9 and Δ11 fatty acid desaturases of P. xylostella. were cloned. Phylogenetic analysis indicated that these two desaturase genes were highly clustered with other desaturases associated with sex pheromone biosynthesis in other insects. RT-PCR analysis showed that Δ9 desaturase was dominantly expressed in adult females, whereas Δ11 desaturase was expressed in all developmental stages. When PBANr expression was suppressed by PBANr-RNAi, the treated females also showed significant suppression of expression of both desaturases. These results suggest that expressions of the two desaturases are controlled by PBAN and that the two desaturases may be involved as downstream components in sex pheromone biosynthesis of P. xylostella.

A cDNA of PBAN receptor (Plx-PBANR) isolated from female pheromone gland of the diamondback moth (DBM, Plutella xylostella (L.) encodes 338 amino acids. Plx-PBANR includes 7 transmembranes, indicating it belongs to G-protein coupled receptor family. Plx-PBANR showed high similarities with other moth PBANRs and its expression was only found in female pheromone gland, demonstrating that pheromone gland is the only molecular target of Plx-PBAN. To accomplish the funcional expression of Plx-PBANR, Human uterus carcinoma was stably transfected with Plx-PBANR gene and Plx-PBANR expression was confirmed by RT-PCR analysis. Plx-PBANR expressing cells increased level of Ca2+ influx when challenged with Plx-PBAN and Hez-PBAN from Heliothis zea, as ionomycin as a positive control does. To inhibit Plx-PBNAR expression in vivo, RNAi fragment for Plx-PBANR was injected into pupae. Suppression of PBANR expression was confirmed by RT-PCR and also induced inhibition of mating behavior in adults, revealing that reproductive organ of the female has no spermatocyte and that there are no successful reproductive behaviors. RNAi-treated adults showed reduced pheromone production. These results suggests that inhibition of PBANR expression affects the molecular biological events of PBAN and eventually suppresses mating behavior.