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.

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.

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 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.

Internal sperm storage after mating is important for insect reproduction, because it permits delayed fertilisation, and post-copulatory mate choice in polyandrous females. The polyandry is common in many animal taxa including insects, because it increases female fitness by reducing the risk of infertility and providing opportunities for sperm competition and choice. The reproductive success of males, on the other hand, often depends upon avoidance of sperm competition by preventing mated females from copulating and receiving sperm from other male suitors. A widespread strategy used by males is the use of the male seminal fluid proteins (SFPs) that form the mating plug and alter female behaviors, for example by suppressing mating receptivity and elevating egg-laying. Under these circumstances, females are expected to evolve mechanism(s) to control exposure to the male SFPs in order to maximize fitness by balancing the positive and negative impacts of polyandry. Here, we discover that Drosophila melanogaster females eject male ejaculates 1-6 h after mating with a stereotypic behaviour, and that this is regulated by a brain neuropeptide pathway composed of diuretic hormone 44 (Dh44), and its receptor Dh44R1. We showed that suppressing Dh44 or Dh44R1 signals in the brain expedites sperm ejection, whereas enhancing Dh44 or Dh44R1 signals delays sperm ejection. This study uncovers a molecular mechanism by which females can influence sperm competition and selection, and counter actively the negative impact of polyandry.

Neuropeptides are the largest group of neurohormones that act in intercellular communication to regulate various physiological and behavioral events during development and reproduction in animals. One of these families is Pyrokinin/PBAN (Pheromone Biosynthesis Activating Neuropeptide) family defined by a similar 5-amino-acid C-terminal sequence (FXPRLamide) that is the active core fragment for these peptides. This motif has been identified from a variety of insect orders, and even a crustacean species. This family of peptides has been implicated in various physiological functions: 1) moth pheromone biosynthesis, 2) larval melanization, 3) moth embryonic and pupal diapause, 4) visceral muscle contraction in the cockroach, 5) fly puparium formation in different insect species. To date, ~159 PBAN/Pyrokinin family peptides have been identified from 40 species. It is one of the largest neuropeptide families in insects; however, the physiological function of most of these peptides is unknown. The mechanism of PBAN control over pheromone production is only well defined for sex pheromone biosynthesis in a limited number of lepidopteran moths. No other insect groups have been reported to regulate pheromone biosynthesis using PBAN. Conventional insecticides target synapses and/or sodium channels that result in neurotoxicity in the nervous system. Unfortunately, this mode of action affects non-target animals as well. These methods remain the major tool for pest control, and the side effects cause many global problems that result in increased environmental and human health expenses. Therefore, we are faced with a requirement to develop new targeted control agents that will lead to pesticides with new modes of action. This is not impossible, but not easy. Every species-specific neuropeptide is expected to play a critical physiological function in metamorphosis and development of insects. There are no exceptions. Our long-standing question is – “how can interference/disruption ofthe insect (neuro)hormonal system be used to discover novel control tools”. To solve this question a novel approach is being applied for finding and screening novel agonist and/or antagonist to gene products, neuropeptide and receptor, from the in vitro system and through virtual modeling. This concept will be a new paradigm opening the window for the next generation of the pest control, and the principle method will be adapted for insect specific pests. Another research interest here will be presented on exocrinal products, such as semiochemicals produced from insects and plants for chemical communication that regulates insect/insect and insect/host interactions. These studies have included the identification of pheromones and the biosynthetic pathway of their production from insects. The ultimate goal of this research is to discover novel biologically-based green pesticides that are environmental-friendly pest control alternatives.

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.

시상하부-뇌하수체-생식소(HPG) 호르몬 축은 유아기와 아동기에는 작동하지 않다가 사춘기 개시 직전에 활성화되는 흥분성 및 억제성 신호들의 복잡한 중추성 조절 네트워크에 의해 조절된다. 최근 주목받고 있는 kisspeptin은 KiSS-1 유전자의 펩타이드 산물로, 최초 orphan receptor로 클로닝된 G protein-coupled receptor 54(GPR54)의 내인성 리간드이다. KiSS-l은 본래 종양전이억제 유전자로 알려졌으나, 최근