Search Results (100)

Chitin synthase (CHS) is essential for maintaining exoskeletal integrity and environmental adaptability in insects. CHS genes are categorized into two types, CHS1 and CHS2. Hemipteran insects possess only the CHS1 gene due to the absence of a peritrophic matrix (PM) in their midgut. However, the identification and functional characterization of the CHS1 gene in Pentatomidae species have not been reported. This study reports the first identification of a CHS gene, ArmaCHS1, from the predatory stink bug, Arma chinensis, and investigates its role in response to temperature stress. The ArmaCHS1 open reading frame spans 4407 bp, encoding a protein of 1468 amino acids, with 14 transmembrane helices and seven N-glycosylation sites. Phylogenetic analysis confirmed its classification within the CHS1 clade, closely related to CHS1 from Halyomorpha halys. qRT-PCR analysis revealed that ArmaCHS1 is predominantly expressed in the exoskeleton and displays developmentally regulated expression (lowest in eggs, highest in adults). Temperature stress experiments demonstrated that ArmaCHS1 expression was significantly upregulated at low temperatures (12 °C, 19 °C) and markedly downregulated at high temperatures (33 °C, 40 °C). These findings indicate that ArmaCHS1 likely contributes to thermal adaptation in A. chinensis by modulating chitin biosynthesis, providing new insights into the environmental stress responses of beneficial predatory insects. Full article

Chitin synthase (CHS) plays a key role in chitin synthesis. CHS1 is ubiquitous in insects, and some studies have found that the RNA interference with CHS1 can hinder three types of molting processes (larva–larva, larva–pupa and pupa–adult). In the present study, the CHS1 of Monochamus alternatus was identified and characterized by a bioinformatics analysis. The developmental stage-specific expression of the MalCHS1 (Monochamus alternatus CHS1) gene was obtained by a RT-qPCR, and the corresponding dsRNA was designed for functional verification. The RNA interference experiment was conducted using the microinjection method, and the injection site was selected from the abdominal segments of fifth-instar larvae. The results showed that after silencing the CHS1 gene, the larvae of M. alternatus showed morphological abnormalities, such as the softening of the body wall, a transparent abdomen and the swelling of somites, indicating that MalCHS1 mediates the molting, growth and development of M. alternatus. RNAi-mediated MalCHS1 gene silencing may become a promising new biological pesticide that can provide a new target gene for pest control. Full article

Anthracnose is recognized as a significant agricultural disease. This study investigates the disease symptoms characterized by black dots on walnut fruits observed in the walnut orchards of Longnan City, Gansu Province, China, in June 2022. These symptoms resemble those of anthracnose reported in previous studies. A strain designated Ht-10 was initially isolated and identified as belonging to the Colletotrichum species based on its morphological features. Pathogenicity tests confirmed that this strain induced pronounced anthracnose symptoms in walnuts, consistent with those originally observed in the field. Subsequently, multilocus phylogenetic analysis, which included partial sequences of the internal transcribed spacer (ITS), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-tubulin2 (TUB2), and chitin synthase (CHS-1) genes of Ht-10, indicated that it most likely clustered with Colletotrichum fioriniae. The determination of biological characteristics revealed that the optimal temperature for the growth of Ht-10 was 25 °C in full light at a pH of 6, with soluble starch and yeast paste serving as the optimal carbon and nitrogen sources, respectively. To our knowledge, this is the first report of C. fioriniae as a causal agent of anthracnose in walnut fruits in China. Full article

Chitin synthase 3 complex assembly begins at the endoplasmic reticulum where the formation of a Chs3/Chs7 complex facilitates its exit from the ER and its transport along the secretory route. In the present study, our work shows that orphan molecules of Chs7 can exit the ER and are later recycled from the early Golgi by coat protein I (COPI) machinery via the adaptor complex Erv41/Erv46. Moreover, an eventual excess of the protein in the Golgi is recognized by the GGA complex and targeted to the vacuole for degradation through the ESCRT machinery. Non-oligomerizable versions of Chs3 can also exit the ER individually and follow a similar route to that of Chs7. We therefore demonstrate the traffic of unassembled CS3 subunits and describe the cellular mechanisms that guarantee the correct assembly of this protein complex at the ER while providing a default traffic route to the vacuole in case of its failure. This traffic route is shared with canonical ER adaptors, such as Erv29 and Erv14, and other components of protein complexes. The comparative analysis of their traffic allows us to discern a cellular program that combines COPI recycling, proteasomal degradation, and vacuolar disposal for maintaining protein homeostasis at the ER. Full article

Chitin synthase is an essential enzyme of the chitin synthesis pathway during molting. In this study, we identified and characterized a chitin synthase (EsCHS) gene in the Chinese mitten crab, Eriocheir sinensis. The spatio-temporal expression and functional role of EsCHS were investigated. The open reading frame of EsCHS was 4725 bp long and encoded 1574 amino acid residues that contained the typical domain structure of the glycosyltransferase family 2. Phylogenetic analysis revealed that EsCHS belongs to the group I chitin synthase family. The expression of EsCHS was found in regenerative limbs, the cuticle and the intestines. During the molting cycle, EsCHS began to increase in the pre-molt stage and reached a significant peak in the post-molt stage. The knockdown of EsCHS resulted in the significant downregulation of chitin biosynthesis pathway genes, including TRE, HK, G6PI, PAGM and UAP. Moreover, the long-term RNAi of EsCHS resulted in thinning procuticles, abnormal molting and high mortality, suggesting that EsCHS is indispensable for the formation of chitin in the cuticle during molting. In conclusion, EsCHS is involved in the chitin biosynthesis pathway and plays an important role in molting in E. sinensis. These findings highlight the potential of incorporating EsCHS into selective breeding programs to optimize molting regulation and improve growth performance in crustacean aquaculture. Full article

Stem blight is a significant disease affecting blueberries worldwide, caused by various pathogens. This study investigated stem blight disease in Ji’an, Jilin Province, China. Fungi isolated from diseased stems were identified as Colletotrichum temperatum, Curvularia austriaca, and Diaporthe unshiuensis based on morphological characters and multi-locus phylogenetic analyses using the internal transcribed spacer (ITS) region, glyceraldehyde 3-phosphate dehydrogenase (gapdh), chitin synthase (chs), actin (act), β-tubulin (tub2), the translation elongation factor 1-alpha (tef1-α), calmodulin (cal), and histone 3 (his3) regions. Pathogenicity test was conducted on detached green blueberry shoots, all shoots inoculated by mycelium plugs presented necrotic lesions with dark brown margins, while the control (PDA plugs) group did not show any symptoms. Koch’s postulates were confirmed by re-isolating the inoculated pathogen from the disease symptoms. The study provides three new host–pathogen records of fungi associated with blueberry stem blight. Full article

Control interventions against mosquito larvae are the primary measure to reduce the adult abundance and risk of arbovirus outbreaks in Europe. One of the most commonly used larvicides in Italy is diflubenzuron (DFB), which targets chitin synthase 1 (chs-1), interrupting the normal development of larvae into adults. Recent studies identified high levels of DFB resistance in Culex pipiens populations from Emilia-Romagna (Italy) associated with I1043L/M/F mutations at position 1043 of the chs-1 gene. The aim of the present study was to assess the circulation of 1043 resistance alleles in Cx. pipiens populations across Italy, outside Emilia-Romagna, with a focus on the Veneto region. Overall, 1032 specimens were genotyped. The 1043L allele was found in all examined Italian regions (Trentino-Alto Adige 19–36%; Veneto 0–91%; Piemonte 11%; Liguria 28%; Lazio 0–8%; Puglia 5%). The highest frequencies (up to >90%) were observed in the Venetian lagoon, where 1043M was also detected (6–11%). Overall, the relatively low frequencies of 1043 mutations despite extensive and longstanding use of DFB in Italy suggest a high fitness cost worthy of further investigations, while their extremely high frequencies in coastal touristic sites point to these sites as the most relevant for resistance monitoring and larvicide rotation. Full article

Phallus impudicus is a fungus used as a medicine and nutrient-rich food. However, the shelf life of mature Phallus impudicus is only a few hours. Therefore, research on its preservation technology is essential for improving its economic value. This study investigated the effects of hexanal concentrations (25–100 μL/L) and treatment time (4–8 h) on the inhibition of peach-shaped Phallus impudicus (CK) maturation and found that the maturation rate was 25% under optimal conditions of 25 μL/L hexanal treatment for 6 h. Quantitative transcriptomic and lipidomic analyses were conducted among CK, mature Phallus impudicus (M-P), and hexanal-treated peach-shaped Phallus impudicus (H-P-P). In total, 2933 and 2746 differentially expressed genes (DEGs) and 156 and 111 differentially abundant lipids (DALs) were identified in CK vs. H-P-P and M-P vs. H-P-P, respectively. Functional analysis demonstrated that hexanal treatment inhibited phospholipase D gene expression and reduced phosphatidic acid abundance, thereby inhibiting the activation of the phosphatidylinositol signaling system and the signal amplification of the cell wall integrity mitogen-activated protein kinase pathway. These blocked signal transductions inhibited the gene expression of most β-glucanases, chitinases and chitin synthases, further affecting cell wall reconstruction. Moreover, hexanal treatment enhanced membrane stability by reducing the monogalactosyl diglyceride/digalactosyl diacylglycerol ratio and increasing the phosphatidylcholine/phosphatidylethanolamine ratio. This study contributed to the development of hexanal treatment as a postharvest preservation technology for Phallus impudicus. Full article

Protoplasts are essential tools for genetic manipulation and functional genomics research in fungi. This study systematically optimized protoplast preparation conditions and examined transcriptional changes throughout the preparation and regeneration processes to elucidate the molecular mechanisms underlying the formation and regeneration of protoplasts in Lyophyllum decastes. The results indicated an optimal protoplast yield of 5.475 × 10⁶ cells/mL under conditions of fungal age at 10 days, digestion time of 2.25 h, enzyme concentration of 2%, and digestion temperature of 28 °C. The Z5 medium supplemented with L. decastes mycelial extract achieved a high regeneration rate of 2.86. RNA-seq analysis revealed 2432 differentially expressed genes (DEGs) during protoplast formation and 5825 DEGs during regeneration. Casein kinase I, cytochrome P450 (CYP52), and redox-regulated input receptor (PEX5) were significantly upregulated during the protoplast stage, while β-1,3-glucan synthase (SKN1), chitin synthase (CHS2), hydrophobin-1, and hydrophobin-2 showed significant upregulation during the protoplast regeneration phase. These findings provide a reference for the efficient preparation and regeneration of protoplasts and offer new insights into the molecular mechanisms of protoplast formation and cell wall regeneration in fungi. Full article

Wireworms are the most destructive soil insect pests affecting horticultural crops. The damage often renders them unsuitable for commercial purposes, resulting in substantial economic losses. RNA interference (RNAi) has been broadly used to inhibit gene functions to control insect populations. It employs double-stranded RNA (dsRNA) to knockdown essential genes in target organisms, rendering them incapable of development or survival. Although it is a robust approach, the primary challenges are identifying effective target genes and delivering their dsRNA into wireworms. Thus, the present study established a liquid ingestion methodology that efficiently delivers dsRNA into wireworms. We then investigated the effects of four target genes on wireworm mortality. The highest mortality rate reached 50% when the gene encoding vacuolar ATPase subunit A was targeted. Its transcript content in the fed wireworms was also significantly reduced. The mortality rates of the other three target genes of vacuolar ATPase subunit E, beta-actin, and chitin synthase 1 were 28%, 33%, and 35%, respectively. This is the first report demonstrating an efficient feeding methodology and the silencing of target genes in wireworms. Our findings indicate that RNAi is an effective alternative method for controlling the wireworm pest, and can be used to develop field treatment strategies. Full article

For the first time, we used an in vitro vs. in vivo experimental design to reveal core pathways under nitrogen deficiency (ND) in an evergreen tree crop. These pathways were related to lignin biosynthesis, cell redox homeostasis, the defense response to fungus, the response to Karrikin, amino acid transmembrane transport, the extracellular region, the cellular protein catabolic process, and aspartic-type endopeptidase activity. In addition, the mitogen-activated protein kinase pathway and ATP synthase (ATP)-binding cassette transporters were significantly upregulated under nitrogen deficiency in vitro and in vivo. Most of the MAPK downstream genes were related to calcium signaling (818 genes) rather than hormone signaling (157 genes). Moreover, the hormone signaling pathway predominantly contained auxin- and abscisic acid-related genes, indicating the crucial role of these hormones in ND response. Overall, 45 transcription factors were upregulated in both experiments, 5 WRKYs, 3 NACs, 2 MYBs, 2 ERFs, HD-Zip, RLP12, bHLH25, RADIALIS-like, and others, suggesting their ND regulation is independent from the presence of a root system. Gene network reconstruction displayed that these transcription factors participate in response to fungus/chitin, suggesting that nitrogen response and pathogen response have common regulation. The upregulation of lignin biosynthesis genes, cytochrome genes, and strigalactone response genes was much more pronounced under in vitro ND as compared to in vivo ND. Several cell wall-related genes were closely associated with cytochromes, indicating their important role in flavanols biosynthesis in tea plant. These results clarify the signaling mechanisms and regulation of the response to nitrogen deficiency in evergreen tree crops. Full article

Chitin, an extracellular polysaccharide, is synthesized by membrane-embedded chitin synthase (CHS) utilizing intracellular substrates. The mechanism of the translocation of synthesized chitin across the membrane to extracellular locations remains unresolved. We prove that the chitin synthase from Phytophthora sojae (PsCHS) is a processive glycosyltransferase, which can rapidly produce and tightly bind with the highly polymerized chitin. We further demonstrate that PsCHS is a bifunctional enzyme, which is necessary and sufficient to translocate the synthesized chitin. PsCHS was purified and then reconstituted into proteoliposomes (PLs). The nascent chitin is generated and protected from chitinase degradation unless detergent solubilizes the PLs, showing that PsCHS translocates the newly produced chitin into the lumen of the PLs. We also attempted to resolve the PsCHS structure of the synthesized chitin-bound state, although it was not successful; the obtained high-resolution structure of the UDP/Mn²⁺-bound state could still assist in describing the characterization of the PsCHS’s transmembrane channel. Consistently, we demonstrate that PsCHS is indispensable and capable of translocating chitin in a process that is tightly coupled to chitin synthesis. Full article

By using a scaffold hopping/ring equivalent and intermediate derivatization strategies, a series of compounds of 2,5-diphenyl-1,3-oxazoline with substituent changes at the 5-phenyl position were prepared, and their acaricidal activity was studied. However, the synthesized 2,5-diphenyl-1,3-oxazolines showed lower activity against mite eggs and larvae compared to the 2,4-diphenyl-1,3-oxazolines with the same substituents. We speculate that there is a significant difference in the spatial extension direction of the substituents between the two skeletons of compounds, resulting in differences in their ability to bind to the potential target chitin synthase 1. This work is helpful in inferring the internal structure of chitin synthase binding pockets. Full article

Timber trees are targets of herbivorous attacks. The identification of genes associated with pest resistance can be accomplished through differential expression analysis using transcriptomes. We reported the de novo assembly of cedar (Cedrela odorata L.) transcriptome and the differential expression of genes involved in herbivore resistance. The assembly and annotation of the transcriptome were obtained using RNAseq from healthy cedar plants and those infested with Chrysobothris yucatanensis. A total of 325.6 million reads were obtained, and 127,031 (97.47%) sequences were successfully assembled. A total of 220 herbivory-related genes were detected, of which 170 genes were annotated using GO terms, and 161 genes with 245 functions were identified—165, 75, and 5 were molecular functions, biological processes, and cellular components, respectively. To protect against herbivorous infestation, trees produce toxins and volatile compounds which are modulated by signaling pathways and gene expression related to molecular functions and biological processes. The limited number of genes identified as cellular components suggests that there are minimal alterations in cellular structure in response to borer attack. The chitin recognition protein, jasmonate ZIM-domain (JAZ) motifs, and response regulator receiver domain were found to be overexpressed, whereas the terpene synthase, cytochrome P450, and protein kinase domain gene families were underexpressed. This is the first report of a cedar transcriptome focusing on genes that are overexpressed in healthy plants and underexpressed in infested plants. This method may be a viable option for identifying genes associated with herbivore resistance. Full article

The Neurospora crassa genome has a gene cluster for the synthesis of galactosaminogalactan (GAG). The gene cluster includes the following: (1) UDP-glucose-4-epimerase to convert UDP-glucose and UDP-N-acetylglucosamine to UDP-galactose and UDP-N-acetylgalactosamine (NCU05133), (2) GAG synthase for the synthesis of an acetylated GAG (NCU05132), (3) GAG deacetylase (/NCW-1/NCU05137), (4) GH135-1, a GAG hydrolase with specificity for N-acetylgalactosamine-containing GAG (NCU05135), and (5) GH114-1, a galactosaminidase with specificity for galactosamine-containing GAG (NCU05136). The deacetylase was previously shown to be a major cell wall glycoprotein and given the name of NCW-1 (non-GPI anchored cell wall protein-1). Characterization of the polysaccharides found in the growth medium from the wild type and the GAG synthase mutant demonstrates that there is a major reduction in the levels of polysaccharides containing galactosamine and N-acetylgalactosamine in the mutant growth medium, providing evidence that the synthase is responsible for the production of a GAG. The analysis also indicates that there are other galactose-containing polysaccharides produced by the fungus. Phenotypic characterization of wild-type and mutant isolates showed that deacetylated GAG from the wild type can function as an adhesin to a glass surface and provides the fungal mat with tensile strength, demonstrating that the deacetylated GAG functions as an intercellular adhesive. The acetylated GAG produced by the deacetylase mutant was found to function as an adhesive for chitin, alumina, celite (diatomaceous earth), activated charcoal, and wheat leaf particulates. Full article