Ultrabithorax regulates Leptinotarsa decemlineata wing development along with insulin and ecdysteroid signaling pathways.

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.

Activin β Is Critical for Larval-Pupal Transition in the 28 Spotted Lady Beetle Henosepilachna vigintioctopunctata.

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.

Identification and Functional Insights of Knickkopf Genes in the Larval Cuticle of .

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.

RNA Interference-Mediated Suppression of Ecdysone Signaling Inhibits Choriogenesis in Two Coleoptera Species.

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.

Crucial roles of specialized chitinases in elytral and hindwing cuticles construction in Leptinotarsa decemlineata.

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.

Identification of chitinase genes and roles in the larval-pupal transition of Leptinotarsa decemlineata.

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.

RNA interference targeting Ras GTPase gene Ran causes larval and adult lethality in Leptinotarsa decemlineata.

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.

The actions of neonicotinoid insecticides on nicotinic acetylcholine subunits Ldα1 and Ldα8 of Leptinotarsa decemlineata and assembled receptors.

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.

The Leptinotarsa forkhead transcription factor O exerts a key function during larval-pupal-adult transition.

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.

Crustacean cardioactive peptide as a stimulator of feeding and a regulator of ecdysis in Leptinotarsa decemlineata.

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.

A switch of microbial flora coupled with ontogenetic niche shift in Leptinotarsa decemlineata.

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.

Complete Genome Sequence of Stenotrophomonas maltophilia Strain CPBW01, Isolated from the Wings of the Colorado Potato Beetle in Xinjiang, China.

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.

Involvement of Leptinotarsa hormone receptor 38 in the larval-pupal transition.

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.

Silencing Taiman impairs larval development in Leptinotarsa decemlineata.

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.

Ecdysone receptor isoforms play distinct roles in larval-pupal-adult transition in Leptinotarsa decemlineata.

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.

Hormonal signaling cascades required for phototaxis switch in wandering Leptinotarsa decemlineata larvae.

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.

RNA interference against the putative insulin receptor substrate gene chico affects metamorphosis in Leptinotarsa decemlineata.

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.

Involvement of methoprene-tolerant (Met) in the determination of the final body size in Leptinotarsa decemlineata (Say) larvae.

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.

Knockdown of a putative insulin-like peptide gene LdILP2 in Leptinotarsa decemlineata by RNA interference impairs pupation and adult emergence.

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.

Knockdown of a nutrient amino acid transporter gene LdNAT1 reduces free neutral amino acid contents and impairs Leptinotarsa decemlineata pupation.

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.

Knockdown of juvenile hormone acid methyl transferase severely affects the performance of Leptinotarsa decemlineata (Say) larvae and adults.

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.

CHARACTERIZATION AND FUNCTIONAL STUDY OF A PUTATIVE JUVENILE HORMONE DIOL KINASE IN THE COLORADO POTATO BEETLE Leptinotarsa decemlineata (Say).

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.

Instar-dependent systemic RNA interference response in Leptinotarsa decemlineata larvae.

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.