Search Results (54)

The Colorado potato beetle (Leptinotarsa decemlineata, CPB) is a major pest in potato crops, notorious for its rapid dispersal and insecticide resistance, which are enabled by its robust elytra and flight-capable hindwings. The Miniature (Mi) gene, encoding a protein with a zona pellucida (ZP) domain, is involved in wing development and cuticle integrity, yet its functional role in beetles remains underexplored. In this study, we cloned and characterized the LdMi gene in the CPB and investigated its function using RNA interference (RNAi), morphological analyses, and spectroscopy. LdMi encodes a 146.35 kDa transmembrane protein with a conserved ZP domain, clusters with coleopteran homologs, and exhibits relative conservation across insect species. Expression profiling showed high LdMi transcript levels in the hindwings, the elytra, and the pupal stages. RNAi knockdown in fourth-instar larvae resulted in severe eclosion defects, including malformed wings and reduced adult weight. Scanning electron microscopy (SEM) revealed disrupted elytral patterns and deformed hindwing veins in knockdown individuals. Spectroscopic analyses using Fourier-transform infrared (FTIR) and Raman spectroscopy indicated a reduction in protein–chitin crosslinking and diminished hydrogen bonding, suggesting compromised cuticular integrity. These results highlight the essential role of LdMi in cuticle formation and the surface morphology of the elytra and hindwings, offering new insights into ZP domain proteins in insects. Full article

The rapid global expansion of Aedes aegypti-borne diseases such as dengue, chikungunya, and Zika has positioned this mosquito as a key target for vector control programs. These programs rely heavily on insecticide use, leading to the widespread emergence of insecticide resistance. Understanding the molecular basis of resistance is essential for developing effective management strategies. In this study, we employed a whole-transcriptome (RNA-seq) approach to analyze gene expression in three Ae. aegypti populations from Mexico that underwent four generations of laboratory selection with deltamethrin. Several cytochrome P450 genes (CYP6AG4, CYP6M5, CYP307A1) and a chitin-binding peritrophin-like gene (Ae-Aper50) were significantly overexpressed following selection, supporting roles for both detoxification and midgut protection. We also observed a consistent downregulation of cuticular protein genes in deltamethrin-selected groups relative to the baseline populations, suggesting their involvement in baseline tolerance rather than induced resistance. Additionally, the overexpression of immune- and stress-related genes, including the RNA helicase MOV-10, indicates that insecticide selection may trigger broader physiological responses. These findings highlight complex, multi-pathway transcriptomic changes associated with resistance development in Ae. aegypti. Full article

Plant cuticles are crucial for protecting plants from various environmental stresses. Seed priming with abscisic acid (ABA) enhances crop stress tolerance, but its molecular mechanisms in cuticular wax and cutin biosynthesis remain unclear. This study investigated ABA-priming’s role in boosting cuticular wax and cutin accumulation in sweet sorghum (Sorghum bicolor L.) using physiological and transcriptomic analyses. Abscisic acid priming increased leaf wax (37.7%) and cutin (25.6%) under drought, reducing water loss (9.8–36.6%) and improving leaf water content (28.4–120%). Transcriptomics identified 921 differentially expressed genes, including key fatty acid biosynthesis genes (ADH2, DES2, KAS2). Co-expression analysis revealed the synergistic regulation of wax and cutin biosynthesis by the abscisic acid and jasmonic acid (JA) pathways. Exogenous ABA and JA application confirmed their roles, with combined treatment increasing wax content by 71.7% under drought stress. These findings were validated in other sweet sorghum cultivars (DLS and ML8000), highlighting the potential of ABA priming as a universal strategy to enhance wax deposition in crops. Our study provides new insights into the molecular mechanisms underlying ABA-induced drought resistance and offers a practical approach for improving crop resilience in water-limited environments. Full article

Plant cuticular wax serves as a critical component for defense against biotic and abiotic stresses, with its biosynthetic pathway regulated by the ECERIFERUM (CER) gene family. This study presents the first genome-wide identification of 79 CER genes (CalCERs) in pepper (Capsicum annuum L.), which are distributed across all 12 chromosomes. Phylogenetic analysis classified CalCERs into five clades, with clade-specific conservation of exon–intron architectures and protein motifs. Promoter cis-element analysis revealed enrichment of light-responsive elements, abscisic acid (ABA), jasmonic acid (JA), and stress-responsive regulatory motifs, indicating multi-pathway regulation. Transcriptomic data highlighted tissue-specific expression patterns, such as the root-predominant express gene CalCER1-2 and the flower-specific express gene CalCER3-1. Under abiotic stresses (drought, salt, heat, and cold), CalCER4-2 and CalCER6-6 responded rapidly, while most genes showed delayed differential expression. Under biotic stress, CalCER3-1 and CalCER5-3 were upregulated, whereas CalCER2-2 exhibited pathogen-specific suppression, suggesting roles in modulating wax-mediated pathogen resistance. Hormone treatments revealed dynamic responses: CalCER2-2 was persistently ABA-inducible, while CalCER3-1 specifically responded to JA. This study underscores evolutionary conservation and species-specific expansion of the pepper CER family, linking their expression to wax biosynthesis and stress adaptation. These insights provide a foundation for enhancing stress resilience in crops. Future work should employ gene editing and metabolomics to validate functional mechanisms and optimize breeding strategies. Full article

Insecticide resistance in mosquitoes has become a severe impediment to global vector control and manifests as decreased insecticide effectiveness. The role of target site mutations and detoxification enzymes as resistance markers has been documented in mosquitoes; however, the emergence of complex resistant phenotypes suggest the occurrence of additional mechanisms. Cuticular proteins (CPs) are key constituents of the insect cuticle, and play critical roles in insect development and insecticide resistance. In this study, via electron microscopy we observed that the leg cuticle thickness in deltamethrin-resistant (DR) Anopheles sinensis mosquitoes was significantly greater than that measured in deltamethrin-susceptible (DS) An. sinensis. Transcription analysis revealed that cuticle proteins were enriched in the legs, including members of the CPR, CPAP, and CPF families. Further comparisons revealed the specific overexpression of four CP genes in the legs of DR An. sinensis; whose expression levels increased after treatment with deltamethrin. The RNAi-mediated silencing of one CP gene, AsCPF1, resulted in a significant decrease in the leg cuticle thickness of DR mosquitoes and significantly elevated the mortality rate when exposed to deltamethrin. These findings suggest that alterations in the An. sinensis leg cuticle contribute to the insecticide resistance phenotype. AsCPF1 is thereby a target study molecule for investigation of its mode of action, and broader attention should be paid to the role of mosquito legs in the development of insecticide resistance. Full article

The annual bluegrass weevil (Listronotus maculicollis Kirby) is a devastating insect pest of annual bluegrass (Poa annua L.) and, to a lesser extent, creeping bentgrass (Agrostis stolonifera L.) on golf courses. Listronotus maculicollis-reared A. stolonifera, a comparatively tolerant host, incurs fitness costs, including longer developmental periods and reduced larval survivorship. This study sought to characterize microbiota diversity in L. maculicollis adults and larvae reared on P. annua and A. stolonifera cultivars (Penncross & A4) to explore whether intrinsic factors, such as microbial community composition, vary across host plants and developmental stages, potentially influencing host suitability. Alpha diversity analyses showed adults feeding on A4 exhibited higher bacterial species richness than their offspring reared on the same cultivar. Beta diversity analysis revealed significant dissimilarities between L. maculicollis adults and offspring regardless of host. Pseudomonas sp. was consistently abundant in larvae across all turfgrasses, indicating a potential association with larval development. Elevated levels of Wolbachia sp., known for insect reproductive manipulation, were observed in adults, but appear to be unrelated to host plant effects. The most prevalent bacterium detected was Candidatus Nardonella, a conserved endosymbiont essential for cuticular hardening in weevils. Given the role of cuticular integrity in insecticide resistance, further investigations into insect–microbe–plant interactions could guide the development of targeted pest management strategies, reducing resistance and improving control measures for L. maculicollis. Full article

Citrus black spot (CBS) is a fungal disease caused by Phyllosticta citricarpa Kiely, (McAlpine Van der Aa), with most cultivars being susceptible to infection. Currently, disease control is based on the application of protective fungicides, which is restricted due to resistance, health and environmental concerns. Although using natural products for disease management is gaining momentum, more advances are required. This study obtained the metabolic profiles of the essential oil and cuticular waxes of two citrus cultivars with a varying susceptibility to CBS infection using gas chromatography–mass spectrometry. A multivariate data analysis identified possible biomarker compounds that contributed to the difference in susceptibility between the two cultivars. Several identified biomarkers were tested in vitro for their antifungal properties against P. citricarpa. Two biomarkers, propanoic acid and linalool, were able to completely inhibit pathogen growth at 750 mg/L and 2000 mg/L, respectively. Full article

Plants face multiple stresses in their natural habitats. WRKY transcription factors (TFs) play an important regulatory role in plant stress signaling, regulating the expression of multiple stress-related genes to improve plant stress resistance. In this study, we analyzed the expression profiles of 25 BnWRKY genes in three stages of ramie growth (the seedling stage, the rapid-growth stage, and the fiber maturity stage) and response to abiotic stress through qRT-PCR. The results indicated that 25 BnWRKY genes play a role in different growth stages of ramie and were induced by salt and drought stress in the root and leaf. We selected BnWRKY49 as a candidate gene for overexpression in Arabidopsis. BnWRKY49 was localized in the nucleus. Overexpression of BnWRKY49 affected root elongation under drought and salt stress at the Arabidopsis seedling stage and exhibited increased tolerance to drought stress. Further research found that BnWRKY49-overexpressing lines showed decreased stomatal size and increased cuticular wax deposition under drought compared with wild type (WT). Antioxidant enzyme activities of SOD, POD, and CAT were higher in the BnWRKY49-overexpressing lines than the WT. These findings suggested that the BnWRKY49 gene played an important role in drought stress tolerance in Arabidopsis and laid the foundation for further research on the functional analysis of the BnWRKYs in ramie. Full article

The mechanisms underlying the recognition of a susceptible host by a fungus and the role of cuticular compounds (CCs) in this process remain unclear; however, accumulated data suggest that this is influenced to a great degree by cuticular lipids. Two insect species differing in their sensitivity to fungal infection, viz. the highly sensitive Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) and the resistant Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae), exhibited significant qualitative and quantitative changes in cuticular free fatty acid (FFA) profiles after exposure to Conidiobolus coronatus (Constantin) Batko (Entomopthorales). Despite being systematically distant, leading different lifestyles in different habitats, both insect species demonstrated similar changes in the same FFAs following exposure to the fungus (C12:0, C13:0, C14:0, C15:0, C16:1, C16:0, C18:1, C18:0), suggesting that these are involved in a contact-induced defense response. As it was not possible to distinguish the share of FFAs present in the conidia that were attached to the cuticle from the FFAs of the cuticle itself in the total number of extracted FFAs, further research is necessary. Full article

Brassica carinata has received considerable attention as a renewable biofuel crop for semi-arid zones due to its high oil content and polyunsaturated fatty acids contents. It is important to develop new drought-resistant cultivars of B. carinata production to expand its areas into more arid regions. The accumulation of leaf cuticular wax on plant surfaces is one mechanism that reduces non-stomatal water loss, thus increasing drought resistance in plants. To explore phenotypic variations in cuticular wax in B. carinata, leaf waxes were extracted and quantified from a diversity panel consisting of 315 accessions. The results indicate that the accessions have a wide range of total leaf wax content (289–1356 µg dm⁻²), wax classes, and their components. The C₂₉ and C₃₁ homologues of alkanes, C₂₉ ketone homologue, C₂₉ secondary alcohol, and C₃₀ aldehyde were the most abundant leaf waxes extracted from B. carinata accessions. The high heritability values of these waxes point to the positive selection for high wax content during early generations of future B. carinata breeding programs. Positive correlation coefficients, combined with the effects of these waxes on leaf wax content accumulation, suggest that modifying specific wax content could increase the total wax content and enhance cuticle composition. The identified leaf wax content and compositions in B. carinata will lead to the future discovery of wax biosynthetic pathways, the dissection of its genetic regulatory networks, the identification of candidate genes controlling production of these waxes, and thus, develop and release new B. carinata drought-tolerant cultivars. Full article

Cucumbers (Cucumis sativus L.) are a global popular vegetable and are widely planted worldwide. However, cucumbers are susceptible to various infectious diseases such as Fusarium and Verticillium wilt, downy and powdery mildew, and bacterial soft rot, which results in substantial economic losses. Grafting is an effective approach widely used to control these diseases. The present study investigated the role of wax and the phenylpropanoid biosynthesis pathway in black-seed pumpkin rootstock-grafted cucumbers. Our results showed that grafted cucumbers had a significantly higher cuticular wax contents on the fruit surface than that of self-rooted cucumbers at all stages observed. A total of 1132 differently expressed genes (DEGs) were detected in grafted cucumbers compared with self-rooted cucumbers. Pathway enrichment analysis revealed that phenylpropanoid biosynthesis, phenylalanine metabolism, plant circadian rhythm, zeatin biosynthesis, and diterpenoid biosynthesis were significantly enriched. In this study, 1 and 13 genes involved in wax biosynthesis and the phenylpropanoid biosynthesis pathway, respectively, were up-regulated in grafted cucumbers. Our data indicated that the up-regulated genes in the wax and phenylpropanoid biosynthesis pathways may contribute to disease resistance in rootstock-grafted cucumbers, which provides promising targets for enhancing disease resistance in cucumbers by genetic manipulation. Full article

Aedes aegypti transmits major arboviruses of public health importance, including dengue, chikungunya, Zika, and yellow fever. The use of insecticides represents the cornerstone of vector control; however, insecticide resistance in Ae. aegypti has become widespread. Understanding the molecular basis of insecticide resistance in this species is crucial to design effective resistance management strategies. Here, we applied Illumina RNA-Seq to study the gene expression patterns associated with resistance to three widely used insecticides (malathion, alphacypermethrin, and lambda-cyhalothrin) in Ae. aegypti populations from two sites (Manatí and Isabela) in Puerto Rico (PR). Cytochrome P450s were the most overexpressed detoxification genes across all resistant phenotypes. Some detoxification genes (CYP6Z7, CYP28A5, CYP9J2, CYP6Z6, CYP6BB2, CYP6M9, and two CYP9F2 orthologs) were commonly overexpressed in mosquitoes that survived exposure to all three insecticides (independent of geographical origin) while others including CYP6BY1 (malathion), GSTD1 (alpha-cypermethrin), CYP4H29 and GSTE6 (lambda-cyhalothrin) were uniquely overexpressed in mosquitoes that survived exposure to specific insecticides. The gene ontology (GO) terms associated with monooxygenase, iron binding, and passive transmembrane transporter activities were significantly enriched in four out of six resistant vs. susceptible comparisons while serine protease activity was elevated in all insecticide-resistant groups relative to the susceptible strain. Interestingly, cuticular-related protein genes (chinase and chitin) were predominantly downregulated, which was also confirmed in the functional enrichment analysis. This RNA-Seq analysis presents a detailed picture of the candidate detoxification genes and other pathways that are potentially associated with pyrethroid and organophosphate resistance in Ae. aegypti populations from PR. These results could inform development of novel molecular tools for detection of resistance-associated gene expression in this important arbovirus vector and guide the design and implementation of resistance management strategies. Full article

Typical orb webs with glue droplets are renewed regularly, sometimes multiple times per night. Such behaviour, however, is rarely found with cribellate spiders. The adhesive portion of their capture threads consist of nanofibres instead of glue, and the fibres interact with the cuticular hydrocarbons (CHCs) of their insect prey for adhesion. Many of these spiders often only add new threads to their existing webs instead of completely reconstructing them. In testing the adhesion force of aged capture threads of three different cribellate species, we indeed did not observe an overall decline in adhesion force, even after a period of over a year. This is in line with the (formulated but so far never tested) hypothesis that when comparing gluey capture threads to nanofibrous ones, one of the benefits of cribellate capture threads could be their notable resistance to drying out or other ageing processes. Full article

Plant cuticular wax plays an important role in resistance to environmental stresses. Eceriferum (CER) genes are involved in wax synthesis. However, little information is available for tomato species. In this study, 26 SlCER genes were identified in tomato (S. lycopersicum), and they were classified into four clades. The physicochemical properties and conserved motifs of their proteins were predicted. These SlCERs were mainly expressed in leaves, flowers or fruits, and most SlCERs played roles in response to abiotic stresses, especially drought stress. Furthermore, the changes in haplotypes indicated that SlCERs might have been involved in adapting to the environments for wild species S. pimpinellifolium before domestication. These findings would lay a foundation for future functional studies of SlCERs and also provide insights for anti-stress improvement in tomato in the near future. Full article

Drought stress is a major production constraint in crops globally. Crop wild relatives are important sources of resistance and tolerance for both biotic and abiotic stresses, respectively. A breeding program was initiated to introgress drought tolerance in sunflowers through hybridization between the wild species Helianthus argophyllus and the cultivated pool of H. annuus. Selection was carried out from the F₂ to F₅ segregating populations for the silver canopy, high cuticular wax, small leaf area, single heading and high oil content. Cuticular wax ranged between 8.72 µg g⁻¹ and 17.19 µg g⁻¹ in the F₅ offspring. The selected F₅ breeding lines were self-pollinated to obtain the F₆ generation. Thereafter, this F₆ was compared with the non-adapted elite sunflower germplasm in a factorial complete randomized design with different water treatments; i.e., comparing fully irrigated (100%, T0) versus 75% (T1), 50% (T2) and 25% (T3) of total irrigation. The comparison between the two types of the germplasm showed that drought-tolerant breeding lines had a comparatively lesser decrease in leaf area (0, 11, 22%) and shoot length (4, 21, 28%) than the elite germplasm, which experienced a decrease in leaf area (21%, 33% and 40%) and shoot length (17, 27 and 34%) under the various drought treatments. Moreover, drought-tolerant breeding lines had 100% more root shoot ratios than the elite germplasm (20%) in T3 when compared with control. Several drought-tolerant promising lines (D-2, D-5 and D-27) were selected due to their high leaf area, great root length and increased root to shoot ratio under T3. Some of the lines could be directly used for the development of drought-tolerant hybrids. Combining ability testing indicated that D-27 (F₇) was a good general combiner for seed yield plant⁻¹ and oil content after mating with male-line RSIN.82. Resulting hybrids could help to minimize seed yield loss due to water stress and to achieve profitable cultivation of sunflowers in arid regions of Pakistan. Full article