Identification of the prothoracicotropic hormone (Ptth) coding gene and localization of its site of expression in the pea aphid Acyrthosiphon pisum

Abstract

Insect hormones control essential aspects of physiology, behaviour and development in insects. The majority of insect hormones are peptide hormones that perform a highly diverse catalogue of functions. Prothoracicotropic hormone (PTTH) is a brain neuropeptide hormone whose main function is to stimulate the secretion of ecdysone (the moulting hormone) by the prothoracic glands in insect larvae thus playing a key role in the control of moulting and metamorphosis. Moreover, both PTTH release or blockade have been reported to act as a switch to terminate or initiate larval and pupal diapauses. In insects, diapause is a prevalent response often regulated by the photoperiod. It has been shown that PTTH participates as an output of the circadian clock and a role in photoperiodic processes is suggested in some insect species. Aphids (Hemiptera: Aphididae) reproduce by cyclical parthenogenesis with a sexual phase, induced by short photoperiods, that leads to the production of diapausing eggs. With the availability of the pea aphid (Acyrthosiphon pisum) genome, efforts to identify and characterize genes relevant to essential aspects of aphid biology have multiplied. In spite of its relevance, several genomic and transcriptomic studies on aphid neuropeptides failed to detect aphid PTTH amongst them. Here we report on the first identification of the aphid PTTH coding gene and the neuroanatomical localization of its expression in the aphid brain.

Induction of diapause by clock proteins period and timeless via changes in PTTH and ecdysteroid titer in the sugar beet moth, Scrobipalpa ocellatella (Lepidoptera: Gelechiidae)

“…However, the signals were detected only in PI, dorsal protocerebrum, and tritocerebrum of diapause pupae (inducing photoperiod of LD 12:12). The cells expressing PTTH were almost like those observed in other insects in terms of position and distribution (Barbera & Matinez-Torres, 2017;Hou & Xu, 2007;McBrayer et al, 2007;Shiga et al, 2003;W. Smith & Rybczynski, 2012).…”

Nezara viridula (Hemiptera: Pentatomidae) transcriptomic analysis and neuropeptidomics

“…Even though NTL does not belong to the basal set, its presence in H. halys genome suggests that it should also be present in N. viridula , although it was not detected in the transcriptome. The remaining components of the variable set (inotosin, NPLPs 2–4, sex peptide, trissin and PTTH) have not been identified in triatomine databases to date 14 , 31 , even though PTTH has been reported in other hemipteran species such as N. lugens 33 and A. pisum 60 , and inotosin was detected in N. lugens 33 . We did not detect these precursors in our genomic, transcriptomic or peptidomic approaches.…”

CBR1 decreases protein carbonyl levels via the ROS/Akt/CREB pathway to extend lifespan in the cotton bollworm, Helicoverpa armigera

“…During diapause initiation, low levels of hormones, such as PTTH [45,46], ecdysone [47], insulin [10], and TGFβ [48], cause low levels of intermediates such as glucose and pyruvate in the blood [36]. Downregulation of intermediates inhibit the metabolic activity of the brain to induce the initiation of diapause [38].…”