Publications by authors named "Kai-Yun Fu"

Leptinotarsa decemlineata (Say) (Colorado potato beetle, CPB) is a notorious pest of potatoes. Its hardened forewings, known as elytra, protect the hindwings and the abdomen against enemies and chemical pesticides. Ubx plays a crucial role in differentiating insect wings, but the molecular mechanism remains unclear.

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The activin cascade is activated when a pair of extracellular ligand (Myoglianin, Myo; Activin β, Actβ; Dawdle, Daw) binds to two pairs of transforming growth factor β (TGF) serine-threonine receptor kinases, TGF-β type I (Baboon, Babo) and II receptors. However, the roles of activin way have not well been explored in non-Drosophilid insects. In the present paper, we compared the functions of Activin β (Actβ) ligand and receptor isoform BaboB in post-embryonic development in a defoliating ladybird Henosepilachna vigintioctopunctata.

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Article Synopsis
  • The Colorado potato beetle, a major pest, uses bright colors to signal its toxicity to predators, which comes from toxic compounds that are still being studied.
  • Research reveals that the beetle’s toxic hydrogen cyanide (HCN) is produced from mandelonitrile and other compounds by a gut bacterium called Proteus vulgaris Ld01, which also synthesizes these compounds through genes.
  • Eliminating this bacterium from the beetle reduces HCN emission and makes them more appealing to predators, as shown in experiments where chickens preferred eating bacteria-deprived larvae over others, demonstrating the importance of gut bacteria in the beetle's defense strategy.
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The Colorado potato beetle () is a major pest of potato crops. While () genes are essential for insect cuticle formation, their roles in pests like remain unclear. This study aims to identify and characterize genes in and explore their functions in larval development and cuticle integrity.

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During choriogenesis in insects, chorion (eggshell) is formed by surrounding follicular epithelial cells in ovarioles. However, the regulatory endocrine factor(s) activating choriogenesis and the effect of chemical components on eggshell deserve further exploration. In two representative coleopterans, a coccinellid and a chrysomelid , genes encoding the 20-hydroxyecdysone (20E) receptor heterodimer, ecdysone receptor (EcR) and ultraspiracle (USP), and two chitin biosynthesis enzymes UDP-N-acetylglucosamine pyrophosphorylase (UAP) and chitin synthase (ChS1), were highly expressed in ovaries of the young females.

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Background: The Colorado potato beetle (CPB), Leptinotarsa decemlineata, is a major potato (Solanum tuberosum) pest, infesting over 16 million km and causing substantial economic losses. The insect cuticle forms an apical extracellular matrix (ECM) envelope covering exposed organs to direct morphogenesis and confer structural protection. While select chitinase (Cht) genes have proven essential for larval development, their potential activities directing ECM remodeling underlying adult wing maturation remain undefined.

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Background: Insect chitinases play crucial roles in degrading chitin in the extracellular matrix, affecting insect development and molting. However, our understanding of the specific functions of various chitinases in Leptinotarsa decemlineata is limited, hindering the deployment of novel gene-targeting technologies as pest management strategies.

Results: We identified and characterized 19 full-length complementary DNA (cDNA) sequences of chitinase genes (LdChts) in Leptinotarsa decemlineata.

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Background: RNA interference (RNAi) is a breakthrough technology in pest control. It is highly efficient to Coleopteran pests such as the Colorado potato beetle Leptinotarsa decemlineata, a serious pest defoliator mainly attacking potatoes worldwide. The first step for effective pest control by RNAi is the development of effective and reliable target genes.

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The insect nicotinic acetylcholine receptor (nAChR) is a pentameric channel protein and also a target for neonicotinoids. There are few reported studies on the molecular interactions of Leptinotarsa decemlineata nAChRs with neonicotinoids. In this study, we analyzed the response of acetylcholine and neonicotinoids (thiamethoxam [TMX], imidacloprid [IMI], and clothianidin [CLO]) on hybrid receptors constructed by nAChR α1 and α8 subunits of L.

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Forkhead box O (FoxO) protein, a major downstream transcription factor of insulin/insulin-like growth factor signaling/target of rapamycin pathway (IIS/TOR), is involved in the regulation of larval growth and the determination of organ size. FoxO also interacts with 20-hydroxyecdysone (20E) and juvenile hormone (JH) signal transduction pathways, and hence is critical for larval development in holometabolans. However, whether FoxO plays a critical role during larval metamorphosis needs to be further determined in Leptinotarsa decemlineata.

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Crustacean cardioactive peptide (CCAP), a highly conserved amidated neuropeptide, stimulates feeding in Drosophila melanogaster and Periplaneta americana, and regulates pupa-adult transition in Tribolium castaneum and Manduca sexta. In the present paper, we intended to address whether CCAP plays the dual roles in the Colorado potato beetle Leptinotarsa decemlineata. We found that the levels of Ldccap were high in the dissected samples of brain-corpora cardiaca-corpora allata complex and ventral nerve cord, midgut and hindgut in the final (fourth)-instar larvae.

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In Leptinotarsa decemlineata, a final-instar wandering larva typically undergoes an ontogenetic niche shift (ONS), from potato plant during the foraging stage to its pupation site below ground. Using high-throughput sequencing of the bacterial 16S ribosomal RNA gene, we determined the hypothesis that the L. decemlineata pupae harbor stage-specific bacteria to meet the physiological requirements for underground habitat.

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Article Synopsis
  • Insect ecdysis triggering hormone (ETH) receptors (ETHRs) are G protein-coupled receptors that, upon binding to ETH, initiate the behavior and physiological processes necessary for insect molting (ecdysis).
  • Different splicing isoforms of the ETH gene (ETHRA and ETHRB) have distinct roles, with ETHRA linked to a series of hormonal activations for ecdysis at all stages, while ETHRB is essential during pupal and adult stages.
  • In a study on the Colorado potato beetle, RNA interference (RNAi) targeting ETH isoforms resulted in developmental arrest in larvae, demonstrating the critical and isoform-specific roles of ETHRA and ETHRB in regulating the transition from larva to pupa.
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Bacteria of the genus are opportunistic and have been documented in the guts of several insect species. Here, we present the complete genome sequence of strain CPBW01, isolated from the wings of the Colorado potato beetle, , collected from potato fields in Urumqi (43.71N, 87.

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In insects, nuclear receptors (NRs) including EcR (NR1H1), USP (NR2B4), E75 (NR1D3), HR3 (NR1F), HR4 (NR6) and FTZ-F1 (NR5A3) mediate the 20-hydroxyecdysone (20E) signaling cascade to play a critical role during larval metamorphosis. In this present paper, we focused on hormone receptor 38 (HR38) in Leptinotarsa decemlineata, the only insect homolog of the NR4A subclass. RNA interference (RNAi) of LdHR38 in the penultimate (third) instar larvae reduced the expression of an ecdysteroidogenesis gene and declined the titer of 20E.

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An exploration of novel control strategies for Leptinotarsa decemlineata is becoming more pressing given rapid evolution of insecticide resistance and rise of production loss of potato. Dietary delivery of bacterially expressed double-stranded RNA (dsRNA) is a promising alternative for management. An important first step is to uncover possible RNA-interference (RNAi)-target genes effective against both young and old larvae.

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A heterodimer of two nuclear receptors, ecdysone receptor (EcR) and ultraspiracle, mediates 20-hydroxyecdysone (20E) signaling to modulate many aspects in insect life, such as molting and metamorphosis, reproduction, diapause and innate immunity. In the present paper, we intended to determine the isoform-specific roles of EcR during larval-pupal-adult transition in the Colorado potato beetle. Double-stranded RNAs (dsRNAs) were prepared using the common (dsEcR) or isoform-specific (dsEcRA, dsEcRB1) regions of EcR as templates.

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Many animals exploit several niches sequentially during their life cycles, a fitness referred to as ontogenetic niche shift (ONS). To successfully accomplish ONS, transition between development stages is often coupled with changes in one or more primitive, instinctive behaviors. Yet, the underlining molecular mechanisms remain elusive.

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It is noted that insect insulin/insulin-like growth factor/target of rapamycin signaling is critical for the regulation of metamorphosis in holometabolous insects. However, the molecular mechanism remains undetermined. Our previous findings reveal that RNA interference (RNAi)-mediated knockdown of an insulin gene (LdILP2) in Leptinotarsa decemlineata disturbs both 20-hydroxyecdysone (20E) and juvenile hormone (JH) signaling, and impairs pupation.

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In the tobacco hornworm Manduca sexta, juvenile hormone (JH) is critical for the control of species-specific size. However, whether the basic helix-loop-helix/Per-Arnt-Sim domain receptor methoprene-tolerant (Met) is involved remains unconfirmed. In the present paper, we found that RNA interference (RNAi)-aided knockdown of Met gene (LdMet) lowered the larval and pupal fresh weights and shortened the larval development period in the Colorado potato beetle Leptinotarsa decemlineata.

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Five insulin-like peptide LdILP genes were identified in Leptinotarsa decemlineata. All of them contained three exons and two introns, with three genes tandemly arrayed and well separated from the other two. Phylogenetic analysis revealed that the three LdILPs from three tandemly-arrayed genes grouped with TcILP1, whereas the other two resembled with TcILP2 and TcILP4 from Tribolium castaneum.

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A Leptinotarsa decemlineata SLC6 NAT gene (LdNAT1) was cloned. LdNAT1 was highly expressed in the larval alimentary canal especially midgut. LdNAT1 mRNA levels were high right after the molt and low just before the molt.

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Background: Juvenile hormone (JH) plays a critical role in the regulation of metamorphosis in Leptinotarsa decemlineata, a notorious defoliator of potato. JH acid methyltransferase (JHAMT) is involved in one of the final steps of JH biosynthesis.

Results: A putative JHAMT cDNA (LdJHAMT) was cloned.

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Juvenile hormone diol kinase (JHDK) is an enzyme involved in JH degradation. In the present article, a putative JHDK cDNA (LdJHDK) was cloned from the Colorado potato beetle Leptinotarsa decemlineata. The cDNA consists of 814 bp, containing a 555 bp open reading frame encoding a 184 amino acid protein.

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RNA interference (RNAi) is a promising approach to control Leptinotarsa decemlineata. In this study, RNAi efficiency by double-stranded RNA (dsRNA) targeting S-adenosyl-L-homocysteine hydrolase (LdSAHase) was compared among L. decemlineata first- to fourth-instar larvae.

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