RESUMO
Piercing-sucking pests are the most notorious group of pests for global agriculture. RNAi-mediated crop protection by foliar application is a promising approach in field trials. However, the effect of this approach on piercing-sucking pests is far from satisfactory due to the limited uptake and transport of double strand RNA (dsRNA) in plants. Therefore, there is an urgent need for more feasible and biocompatible dsRNA delivery approaches to better control piercing-sucking pests. Here, we report that foliar application of layered double hydroxide (LDH)-loaded dsRNA can effectively disrupt Panonychus citri at multiple developmental stages. MgAl-LDH-dsRNA targeting Chitinase (Chit) gene significantly promoted the RNAi efficiency and then increased the mortality of P. citri nymphs by enhancing dsRNA stability in gut, promoting the adhesion of dsRNA onto leaf surface, facilitating dsRNA internalization into leaf cells, and delivering dsRNA from the stem to the leaf via the vascular system of pomelo plants. Finally, this delivery pathway based on other metal elements such as iron (MgFe-LDH) was also found to significantly improve the protection against P. citri and the nymphs or larvae of Diaphorina citri and Aphis gossypii, two other important piercing-sucking hemipeteran pests, indicating the universality of nanoparticles LDH in promoting the RNAi efficiency and mortality of piercing-sucking pests. Collectively, this study provides insights into the synergistic mechanism for nano-dsRNA systemic translocation in plants, and proposes a potential eco-friendly control strategy for piercing-sucking pests.
Assuntos
Hidróxidos , Interferência de RNA , RNA de Cadeia Dupla , Animais , Hidróxidos/química , Hidróxidos/farmacologia , Nanopartículas/química , Ninfa , Hemípteros , Folhas de Planta , Larva , Quitinases/metabolismo , Quitinases/genética , CitrusRESUMO
This study aimed to evaluate the genomic profile of the Antarctic marine Curtobacterium sp. CBMAI 2942, as well as to optimize the conditions for chitinase production and antifungal potential for biological control. Assembly and annotation of the genome confirmed the genomic potential for chitinase synthesis, revealing two ChBDs of chitin binding (Chi C). The optimization enzyme production using an experimental design resulted in a 3.7-fold increase in chitinase production. The chitinase enzyme was identified by SDS-PAGE and confirmed through mass spectrometry analysis. The enzymatic extract obtained using acetone showed antifungal activity against the phytopathogenic fungus Aspergillus sp. series Nigri CBMAI 1846. The genetic capability of Curtobacterium sp. CBMAI 2942 for chitin degradation was confirmed through genomic analysis. The basal culture medium was adjusted, and the chitinase produced by this isolate from Antarctica showed significant inhibition against Aspergillus sp. Nigri series CBMAI 1846, which is a tomato phytopathogenic fungus. This suggests that this marine bacterium could potentially be used as a biological control of agricultural pests.
Assuntos
Antifúngicos , Quitinases , Proteômica , Quitinases/metabolismo , Quitinases/genética , Quitinases/farmacologia , Antifúngicos/farmacologia , Regiões Antárticas , Proteômica/métodos , Genômica/métodos , Aspergillus/enzimologia , Aspergillus/genética , Genoma Bacteriano , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Organismos Aquáticos , Quitina/farmacologia , Quitina/metabolismo , Quitina/químicaRESUMO
Chitin is the second most prevalent polysaccharide found in nature, following cellulose. Amino-oligosaccharides, the byproducts of chitin degradation, exhibit favorable biological properties and potential for various uses. Chitinases play a crucial function in the breakdown of chitin, and their exceptionally effective production has garnered significant interest. Here, in this study, the exochitinase PbChiA, obtained from Paenibacillus barengoltzii, was recombinantly produced and immobilized using the CotG surface protein of Bacillus subtilis WB800N. The resulting strain Bacillus subtilis WB800N pHS-CotG-Chi exhibited exceptional heat stability and efficacy across various pH levels. The chitinolytic activity of the enzyme, which had been isolated and immobilized on the spore surface, was measured to be approximately 16.06 U/mL. Including Ni2+, Zn+2, and K+, and EDTA at various concentration levels in the reaction system, has significantly enhanced the activity of the immobilized enzyme. The immobilized exochitinase demonstrated a notable rate of recycling, as the recombinant spores sustained a relative enzyme activity of more than 70% after three cycles and 62.7% after four cycles. These findings established a basis for additional investigation into the role and practical use of the immobilized bacterial exochitinase in industry.
Assuntos
Bacillus subtilis , Quitinases , Estabilidade Enzimática , Proteínas Recombinantes , Bacillus subtilis/enzimologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Quitina/química , Quitina/metabolismo , Quitinases/metabolismo , Quitinases/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Concentração de Íons de Hidrogênio , Paenibacillus/enzimologia , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Esporos Bacterianos/enzimologia , TemperaturaRESUMO
Sugarcane (Saccharum spp.)is an economically useful crop grown globally for sugar, ethanol and biofuel production. The crop is vulnerable to fungus Colletotrichum falcatum known to cause red rot disease. The pathogen hydrolyses stalk parenchyma cells where sucrose is accumulated resulting in upto 75% losses in sugar recovery. In this study, transgenic sugarcane having resistance against red rot was developed by introducing Trichoderma spp. endochitinase following Agrobacterium mediated transformation. The transgene introduction and expression in genetically modified plants were verified through qRT-PCR revealing upto 6-fold enhancement in endochitinase expression than non-transgenic plants. Hyperspectral Imaging of transgenic plants displayed altered leaf reflectance spectra and vegetative indices that were positively correlated with ransgene expression. The bioassay with virulent pathotypes of C. falcatumCF08 and CF13 known for epiphytotic occurrence resulted in identification of resistant plant Chit 3-13.The plants with higher reflectance also displayed improved disease resistance, implying their early classification into resistant/susceptible. The losses in sucrose content were minimized (up to 4-fold) in inoculated resistant plant Chit 3-13 as compared to susceptible non-transgenic plant, and a fewer pathogen hyphae were detected in vascular cells of the former through optical microscopy. The electron micrographs confirmed sucrose-filled stalk parenchyma cells in Chit 3-13; in contrast, cells of non-transgenic inoculated plant were depleted of sucrose. The active sites involved in cleaving 1-4 ß-glycoside bonds of N-acetyl-d-glucosaminein the pathogen hyphal walls were detected through endochitinase protein structural modelling. The transgenic sugarcane is an important source for in trogressingred rot resistance in plant breeding programs.
Assuntos
Quitinases , Colletotrichum , Resistência à Doença , Doenças das Plantas , Plantas Geneticamente Modificadas , Saccharum , Trichoderma , Saccharum/microbiologia , Saccharum/genética , Resistência à Doença/genética , Plantas Geneticamente Modificadas/microbiologia , Plantas Geneticamente Modificadas/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Colletotrichum/patogenicidade , Trichoderma/genética , Quitinases/genética , Quitinases/metabolismo , Folhas de Planta/microbiologia , Folhas de Planta/genéticaRESUMO
N-acetyl-D-glucosamine and its dimer are degradation products of chitin waste with great potential in therapeutic and agricultural applications. However, the hydrolysis of insoluble chitin by chitinases remains a major bottleneck. This study investigated the biochemical properties and catalytic mechanisms of PoChi chitinase obtained from Penicillium oxalicum with a focus on enhancing its efficiency during the degradation of insoluble chitin. Recombinant plasmids were engineered to incorporate chitin-binding (ChBD) and/or fibronectin III (FnIII) domains. Notably, PoChi-FnIII-ChBD exhibited the highest substrate affinity (Km = 2.7 mg/mL) and a specific activity of 15.4 U/mg, which surpasses those of previously reported chitinases. These findings highlight the potential of engineered chitinases in advancing industrial biotechnology applications and offer a promising approach to more sustainable chitin waste management.
Assuntos
Quitina , Quitinases , Penicillium , Quitinases/metabolismo , Quitinases/genética , Quitina/metabolismo , Penicillium/enzimologia , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/genética , Hidrólise , Engenharia de Proteínas/métodos , Solubilidade , CinéticaRESUMO
Nematodes do not merely siphon off plant resources but also sabotage the plant's mutualistic relationships with beneficial microbes. Yang and colleagues elegantly elucidated this generalizable molecular antagonism, revealing how Heterodera glycines, the notorious soybean cyst nematode (SCN), suppresses beneficial microbial symbiosis through a specific chitinase, HgCht2.
Assuntos
Quitinases , Simbiose , Animais , Quitinases/metabolismo , Glycine max/parasitologia , Glycine max/microbiologia , Tylenchoidea/fisiologia , Nematoides/microbiologiaRESUMO
Effector secretion is crucial for root endophytes to establish and protect their ecological niche. We used time-resolved transcriptomics to monitor effector gene expression dynamics in two closely related Sebacinales, Serendipita indica and Serendipita vermifera, during symbiosis with three plant species, competition with the phytopathogenic fungus Bipolaris sorokiniana, and cooperation with root-associated bacteria. We observed increased effector gene expression in response to biotic interactions, particularly with plants, indicating their importance in host colonization. Some effectors responded to both plants and microbes, suggesting dual roles in intermicrobial competition and plant-microbe interactions. A subset of putative antimicrobial effectors, including a GH18-CBM5 chitinase, was induced exclusively by microbes. Functional analyses of this chitinase revealed its antimicrobial and plant-protective properties. We conclude that dynamic effector gene expression underpins the ability of Sebacinales to thrive in diverse ecological niches with a single fungal chitinase contributing substantially to niche defense.
Assuntos
Quitinases , Endófitos , Raízes de Plantas , Transcriptoma , Quitinases/metabolismo , Quitinases/genética , Raízes de Plantas/microbiologia , Transcriptoma/genética , Anti-Infecciosos/farmacologia , Anti-Infecciosos/metabolismo , Simbiose/genética , Ascomicetos/fisiologia , Ascomicetos/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação Fúngica da Expressão Gênica/efeitos dos fármacosRESUMO
The interaction between bacteria and the intestinal mucus is crucial during the early pathogenesis of many enteric diseases in mammals. A critical step in this process employed by both commensal and pathogenic bacteria focuses on the breakdown of the protective layer presented by the intestinal mucus by mucolytic enzymes. C. perfringens type G, the causative agent of necrotic enteritis in broilers, produces two glycosyl hydrolase family 18 chitinases, ChiA and ChiB, which display distinct substrate preferences. Whereas ChiB preferentially processes linear substrates such as chitin, ChiA prefers larger and more branched substrates, such as carbohydrates presented by the chicken intestinal mucus. Here, we show via crystal structures of ChiA and ChiB in the apo and ligand-bound forms that the two enzymes display structural features that explain their substrate preferences providing a structural blueprint for further interrogation of their function and inhibition. This research focusses on the roles of ChiA and ChiB in bacterial proliferation and mucosal attachment, two processes leading to colonization and invasion of the gut. ChiA and ChiB, either supplemented or produced by the bacteria, led to a significant increase in C. perfringens growth. In addition to nutrient acquisition, the importance of chitinases in bacterial attachment to the mucus layer was shown using an in vitro binding assay of C. perfringens to chicken intestinal mucus. Both an in vivo colonization trial and a necrotic enteritis trial were conducted, demonstrating that a ChiA chitinase mutant strain was less capable to colonize the intestine and was hampered in its disease-causing ability as compared to the wild-type strain. Our findings reveal that the pathogen-specific chitinases produced by C. perfringens type G strains play a fundamental role during colonization, suggesting their potential as vaccine targets.
Assuntos
Galinhas , Quitinases , Infecções por Clostridium , Clostridium perfringens , Enterite , Doenças das Aves Domésticas , Animais , Clostridium perfringens/enzimologia , Clostridium perfringens/patogenicidade , Galinhas/microbiologia , Quitinases/metabolismo , Quitinases/genética , Doenças das Aves Domésticas/microbiologia , Infecções por Clostridium/microbiologia , Infecções por Clostridium/veterinária , Enterite/microbiologia , Necrose , Mucosa Intestinal/microbiologia , Mucosa Intestinal/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genéticaRESUMO
Chitinases play an important role in the molting process of insects and are potential targets for the development of green insecticides. Based on the feature that the +1/+2 sites in OfChtI, OfChtII, and OfChi-h have tryptophan residues in mismatch-parallel position, a strategy to introduce indole scaffold into chitinase inhibitors was proposed, and multitarget chitinase inhibitors containing N-methylcarbamoylguanidinyl and indole scaffold were successfully synthesized. The inhibitory activity showed that compound 8u exhibited significant inhibitory activity against OfChtI, OfChtII, and OfChi-h, with IC50 values of 0.7, 0.79, and 0.58 µM, and Ki values of 0.05 ± 0.005, 0.065 ± 0.004, and 0.025 ± 0.006 µM, respectively. In vivo insecticidal activity showed that compounds 8a and 8g exhibited excellent insecticidal activity against Plutella xylostella and Mythimna separata, with LC50 values of 0.79 and 9.17 mg/L against P. xylostella, respectively, and 3.58 and 83.09 mg/L against M. separata, respectively, making them the most potent chitinase inhibitors with in vivo insecticidal activity discovered to date. The inhibition mechanism and binding free energy results suggested that N-methylcarbamoylguanidinyl binds to the -1 catalytic site, while additional interactions acquired by π-π stacking and hydrophobic interactions of the indole scaffold with tryptophan increase the binding affinity of the targets to chitinases. This work provides a new direction for the development of chitinase inhibitors with compounds 8a and 8g potentially serving as promising candidates for pesticide development.
Assuntos
Quitinases , Desenho de Fármacos , Inibidores Enzimáticos , Indóis , Inseticidas , Mariposas , Quitinases/antagonistas & inibidores , Quitinases/química , Quitinases/metabolismo , Inseticidas/química , Inseticidas/farmacologia , Inseticidas/síntese química , Animais , Mariposas/efeitos dos fármacos , Relação Estrutura-Atividade , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/síntese química , Indóis/química , Indóis/farmacologia , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Simulação de Acoplamento Molecular , Estrutura MolecularRESUMO
Colletotrichum boninense is the main pathogenic fungus causing leaf spot disease in Sorghum sudangrass hybrids, which seriously impairs its quality and yield. In order to find an efficient and green means of control, this study used the agar disk diffusion method to screen for a fungicide with the strongest inhibitory effect on C. boninense from among several bacteria, fungi, and chemicals. Then, the changes in the plant's antioxidant system and metabolic levels after treatment were used to compare the three means of control. The lowest inhibitory concentration of Zalfexam was 10 mg/mL, at which point C. boninense did not grow, and the inhibition rates of Bacillus velezensis (X7) and Trichoderma harzianum were 33.87-51.85% and 77.86-80.56%, respectively. Superoxide dismutase (SOD) and chitinase were up-regulated 2.43 and 1.24 folds in the Trichoderma harzianum group (M group) and SOD activity was up-regulated 2.2 folds in the Bacillus velezensis group (X7 group) compared to the control group (CK group). SOD, peroxidase (POD), and chitinase activities were elevated in the Zalfexam group (HX group). The differential metabolites in different treatment groups were mainly enriched in amino acid metabolism and production, flavonoid production, and lipid metabolism pathways. Compared with the diseased plants (ZB group), the M, X7, HX, and CK groups were co-enriched in the tryptophan metabolic pathway and glutamate-arginine metabolic pathway, and only the CK group showed a down-regulation of the metabolites in the two common pathways, while the metabolites of the common pathways were up-regulated in the M, X7, and HX groups. In addition, the salicylic acid-jasmonic acid pathway and ascorbic acid-glutathione, which were unique to the M group, played an important role in helping Sorghum sudangrass hybrids to acquire systemic resistance against stress. This study fills the gap in the control of Colletotrichum boninene, which causes leaf spot disease in Sorghum sudangrass hybrids. This paper represents the first reported case of biological control for leaf spot disease in Sorghum sudangrass hybrids and provides a reference for the control of leaf spot disease in Sorghum sudangrass hybrids as well as other crops infected with Colletotrichum boninense.
Assuntos
Antioxidantes , Bacillus , Colletotrichum , Doenças das Plantas , Sorghum , Sorghum/microbiologia , Sorghum/metabolismo , Antioxidantes/metabolismo , Doenças das Plantas/microbiologia , Bacillus/metabolismo , Hypocreales/metabolismo , Superóxido Dismutase/metabolismo , Quitinases/metabolismo , Fungicidas Industriais/farmacologiaRESUMO
Yeast cell wall chitin has been shown to bind grape pathogenesis-related chitinases that are the primary cause of protein haze in wines, suggesting that yeast cell walls may be applied for haze protection. Here, we present a high-throughput screen to identify yeast strains with high cell wall chitin using a reiterative enrichment strategy and fluorescence-activated cell sorting of cells labelled with either GFP-tagged chitinase or Calcofluor white. To assess the validity of the strategy, we first used a pooled deletion strain library of Saccharomyces cerevisiae. The strategy enriched for deletion mutants with genes that had previously been described as having an impact on chitin levels. Genes that had not previously been linked to chitin biosynthesis or deposition were also identified. These genes are involved in cell wall maintenance and/or membrane trafficking functions. The strategy was then applied to a mutagenized population of a commercial wine yeast strain, S. cerevisiae EC1118. Enriched mutant strains showed significantly higher cell wall chitin than the wild type and significantly reduced the activity of chitinases in synthetic model wine, suggesting that these strains may be able to reduce haze formation in wine.
Assuntos
Parede Celular , Quitina , Quitinases , Citometria de Fluxo , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Parede Celular/metabolismo , Quitina/metabolismo , Quitinases/genética , Quitinases/metabolismo , Deleção de Genes , Vinho/microbiologia , Ensaios de Triagem em Larga Escala , BenzenossulfonatosRESUMO
Poplar is a valuable tree species that is distributed all over the world. However, many insect pests infest poplar trees and have caused significant damage. To control poplar pests, we transformed a poplar species, Populus davidianaâ ×â P. bolleana Loucne, with the dsRNA of the chitinase gene of a poplar defoliator, Clostera anastomosis (Linnaeus) (Lepidoptera: Notodontidae), employing an Agrobaterium-mediated approach. The transgenic plant has been identified by cloning the T-DNA flanking sequences using TAIL-PCR and quantifying the expression of the dsRNA using qPCR. The toxicity assay of the transgenic poplar lines was carried out by feeding the target insect species (C. anastomosis). The results showed that, in C. anastomosis, the activity of chitinase was significantly decreased, consistent with the expression on mRNA levels, and the larval mortality was significantly increased. These results suggested that the transgenic poplar of dsRNA could be used for pest control.
Assuntos
Quitinases , Larva , Mariposas , Plantas Geneticamente Modificadas , Populus , RNA de Cadeia Dupla , Animais , Populus/genética , Quitinases/genética , Quitinases/metabolismo , Mariposas/genética , Mariposas/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/genética , Controle Biológico de Vetores , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismoRESUMO
BACKGROUND: Soil-borne plant diseases represent a severe problem that negatively impacts the production of food crops. Actinobacteria play a vital role in biocontrolling soil-borne fungi. AIM AND OBJECTIVES: The target of the present study is to test the antagonistic activity of chitinase-producing Streptomyces cellulosae Actino 48 (accession number, MT573878) against Rhizoctonia solani. Subsequently, maximization of Actino 48 production using different fermentation processes in a stirred tank bioreactor. Finally, preparation of bio-friendly formulations prepared from the culture broth of Actino 48 using talc powder (TP) and bentonite in a natural as well as nano forms as carriers. Meanwhile, investigating their activities in reducing the damping-off and root rot diseases of peanut plants, infected by R. solani under greenhouse conditions. RESULTS: Actino 48 was found to be the most significant antagonistic isolate strain at p ≤ 0.05 and showed the highest inhibition percentage of fungal mycelium growth, which reached 97%. The results of scanning electron microscope (SEM) images analysis showed a large reduction in R. solani mycelia mass. Additionally, many aberrations changes and fungal hypha damages were found. Batch fermentation No. 2, which was performed using agitation speed of 200 rpm, achieved high chitinase activity of 0.1163 U mL- 1 min- 1 with a yield coefficient of 0.004 U mL- 1 min- 1 chitinase activity/g chitin. Nano-talc formulation of Actino 48 had more a significant effect compared to the other formulations in reducing percentages of damping-off and root rot diseases that equal to 19.05% and 4.76% with reduction percentages of 60% and 80%, respectively. The healthy survival percentage of peanut plants recorded 76.19%. Furthermore, the nano-talc formulation of Actino 48 was sufficient in increasing the dry weight of the peanut plants shoot, root systems, and the total number of peanut pods with increasing percentages of 47.62%, 55.62%, and 38.07%, respectively. CONCLUSION: The bio-friendly formulations of actinobacteria resulting from this investigation may play an active role in managing soil-borne diseases.
Assuntos
Arachis , Quitinases , Fermentação , Doenças das Plantas , Rhizoctonia , Streptomyces , Streptomyces/enzimologia , Rhizoctonia/fisiologia , Quitinases/metabolismo , Arachis/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Raízes de Plantas/microbiologiaRESUMO
With the emergence of multidrug-resistant microorganisms, microbial agents have become a serious global threat, affecting human health and various plants. Therefore, new therapeutic alternatives, such as chitin-binding proteins, are necessary. Chitin is an essential component of the fungal cell wall, and chitin-binding proteins exhibit antifungal activity. In the present study, chitin-binding peptides isolated from Capsicum chinense seeds were characterized and evaluated for their in vitro antimicrobial effect against the growth of Candida and Fusarium fungi. Proteins were extracted from the seeds and subsequently the chitin-binding proteins were separated by chitin affinity chromatography. After chromatography, two fractions, Cc-F1 (not retained on the column) and Cc-F2 (retained on the column), were obtained. Electrophoresis revealed major protein bands between 6.5 and 26.6 kDa for Cc-F1 and only a ~ 6.5 kDa protein band for Cc-F2, which was subsequently subjected to mass spectrometry. The protein showed similarity with hevein-like and endochitinase and was then named Cc-Hev. Data are available via ProteomeXchange with identifier PXD054607. Next, we predicted the three-dimensional structure of the peptides and performed a peptide docking with (NAG)3. Subsequently, growth inhibition assays were performed to evaluate the ability of the peptides to inhibit microorganism growth. Cc-Hev inhibited the growth of C. albicans (up to 75% inhibition) and C. tropicalis (100% inhibition) and induced a 65% decrease in cell viability for C. albicans and 100% for C. tropicalis. Based on these results, new techniques to combat fungal diseases could be developed through biotechnological applications; therefore, further studies are needed.
Assuntos
Antifúngicos , Candida , Capsicum , Quitina , Quitinases , Fusarium , Sementes , Sementes/química , Antifúngicos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/química , Antifúngicos/metabolismo , Quitina/metabolismo , Quitina/farmacologia , Fusarium/efeitos dos fármacos , Quitinases/farmacologia , Quitinases/metabolismo , Quitinases/química , Quitinases/isolamento & purificação , Candida/efeitos dos fármacos , Candida/enzimologia , Lectinas de Plantas/farmacologia , Lectinas de Plantas/química , Lectinas de Plantas/isolamento & purificação , Testes de Sensibilidade Microbiana , Peptídeos/farmacologia , Peptídeos/química , Peptídeos/isolamento & purificação , Peptídeos/metabolismo , Simulação de Acoplamento Molecular , Proteínas de Plantas/farmacologia , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Peptídeos Catiônicos AntimicrobianosRESUMO
Previous studies have demonstrated the presence of chitinase in Bacillus velezensis through extensive genomic sequencing and experimental analyses. However, the detailed structure, functional roles, and antifungal activity of these chitinases remain poorly characterized. In this study, genomic screening identified three genes-chiA, chiB, and lpmo10-associated with chitinase degradation in B. velezensis S161. These genes encode chitinases ChiA and ChiB, and lytic polysaccharide monooxygenase LPMO10. Both ChiA and ChiB contain two CBM50 binding domains and one catalytic domain, whereas LPMO10 includes a signal peptide and a single catalytic domain. The chitinases ChiA, its truncated variant ChiA2, and ChiB were heterologously expressed in Escherichia coli. The purified enzymes efficiently degraded colloidal chitin and inhibited the spore germination of Penicillium digitatum. Notably, even after losing one CBM50 domain, the resultant enzyme, consisting of the remaining CBM50 domain and the catalytic domain, maintained its colloidal chitin hydrolysis and antifungal activity, indicating commendable stability. These results underscore the role of B. velezensis chitinases in suppressing plant pathogenic fungi and provide a solid foundation for developing and applying chitinase-based biocontrol strategies.
Assuntos
Antifúngicos , Bacillus , Quitinases , Penicillium , Antifúngicos/farmacologia , Antifúngicos/química , Bacillus/enzimologia , Bacillus/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/farmacologia , Quitina/química , Quitinases/química , Quitinases/farmacologia , Escherichia coli , Penicillium/efeitos dos fármacos , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacologiaRESUMO
The direct enzymatic conversion of untreated waste shrimp and crab shells has been a key problem that plagues the large-scale utilization of chitin biological resources. The microorganisms in soil samples were enriched in two stages with powdered chitin (CP) and shrimp shell powder (SSP) as substrates. The enrichment microbiota XHQ10 with SSP degradation ability was obtained. The activities of chitinase and lytic polysaccharide monooxygenase of XHQ10 were 1.46 and 54.62 U/mL. Metagenomic analysis showed that Chitinolyticbacter meiyuanensis, Chitiniphilus shinanonensis, and Chitinimonas koreensis, with excellent chitin degradation performance, were highly enriched in XHQ10. Chitin oligosaccharides (CHOSs) are produced by XHQ10 through enzyme induction and two-stage temperature control technology, which contains CHOSs with a degree of polymerization (DP) more significant than ten and has excellent antioxidant activity. This work is the first study on the direct enzymatic preparation of CHOSs from SSP using enrichment microbiota, which provides a new path for the large-scale utilization of chitin bioresources.
Assuntos
Exoesqueleto , Quitina , Quitinases , Microbiota , Oligossacarídeos , Quitina/química , Animais , Oligossacarídeos/química , Quitinases/metabolismo , Exoesqueleto/química , Metagenômica/métodos , Temperatura , Polimerização , BactériasRESUMO
The natural polymer chitin is an abundant source for valuable N-acetylchitooligosaccharides and N-acetylglucosamine applicable in several industries. The endochitinase Chit36-TA from Trichoderma asperellum was recombinantly expressed in Komagataella phaffii for the enzymatic degradation of chitin from unused insect exuviae into N-acetylchitooligosaccharides. Chit36-TA was purified by Ni-NTA affinity chromatography and subsequently biochemically characterized. After deglycosylation, the endochitinase had a molecular weight of 36 kDa. The optimum pH for Chit36-TA was 4.5. The temperature maximum of Chit36-TA was determined to be 50 °C, while it maintained > 93% activity up to 60 °C. The chitinase was thermostable up to 45 °C and exhibited ~ 50% activity after a 15 min incubation at 57 °C. Chit36-TA had a maximum specific enzyme activity of 50 nkat/mg with a Km value of 289 µM with 4-methylumbelliferyl-N,N',Nâ³-triacetyl-ß-chitotrioside as substrate. Most tested cations, organic solvents and reagents were well-tolerated by the endochitinase, except for SDS (1 mM), Cu2+ (10 mM) and Mn2+ (10 mM), which had stronger inhibitory effects with residual activities of 3, 41 and 28%, respectively. With a degree of hydrolysis of 32% applying colloidal shrimp chitin (1% (w/v)) and 12% on insect larvae (1% (w/v)) after 24 h, the endochitinase was found to be suitable for the conversion of colloidal chitin as well as chitin from black soldier fly larvae into water-soluble N-acetylchitooligosaccharides. To prove scalability, a bioreactor process was developed in which a 55-fold higher enzyme activity of 49 µkat/l and a tenfold higher protein expression of 1258 mg/l were achieved.
Assuntos
Quitina , Quitinases , Hypocreales , Proteínas Recombinantes , Animais , Quitina/metabolismo , Quitina/química , Quitinases/química , Quitinases/metabolismo , Quitinases/genética , Quitinases/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Hypocreales/enzimologia , Simuliidae , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/biossíntese , Saccharomycetales/enzimologia , Concentração de Íons de HidrogênioRESUMO
The first steps in chitin degradation in marine bacteria involve chitinase, which produces N,N'-diacetylchitobiose (GlcNAc)2 from chitin. Moreover, in Vibrio bacteria, chitinase activity is enhanced by heterodisaccharide ß-N-acetyl-d-glucosaminyl-(1,4)-d-glucosamine (GlcNAc-GlcN) produced from (GlcNAc)2 by chitin oligosaccharide deacetylase (COD). However, the role of COD in other marine bacteria, such as Shewanella, remains unexplored. This study investigates GlcNAc-GlcN's impact on chitinase gene expression and enzyme production in S. baltica ATCC BAA-1091, drawing parallels with Vibrio parahaemolyticus RIMD2210633. Using real-time quantitative PCR, the study assesses the upregulation of chitinase gene expression in S. baltica in response to GlcNAc-GlcN, informed by COD's known ability to produce GlcNAc-GlcN from (GlcNAc)2. In Vibrio, GlcNAc-GlcN considerably upregulates chitinase gene expression. This study posits a similar regulatory mechanism in S. baltica, with preliminary investigations indicating COD's capacity to produce GlcNAc-GlcN. This study highlights the importance of exploring GlcNAc-GlcN's regulatory role in chitin metabolism across diverse marine bacteria. The potential induction of chitinase production in S. baltica suggests broader ecological implications. Further research is crucial for a comprehensive understanding of chitin utilization and regulatory pathways in marine bacterial genera.
Assuntos
Quitina , Quitinases , Shewanella , Regulação para Cima , Quitinases/genética , Quitinases/metabolismo , Quitina/metabolismo , Shewanella/genética , Shewanella/enzimologia , Shewanella/efeitos dos fármacos , Acetilglucosamina/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Amidoidrolases/genética , Amidoidrolases/metabolismoRESUMO
GH19 (glycoside hydrolase 19) chitinases play crucial roles in the enzymatic conversion of chitin and biocontrol of phytopathogenic fungi. Herein, a novel multifunctional chitinase of GH19 (CaChi19A), which contains three chitin-binding domains (ChBDs), was successfully cloned from Chitinilyticum aquatile CSC-1 and heterologously expressed in Escherichia coli. We also generated truncated mutants of CaChi19A_ΔI, CaChi19A_ΔIΔII, and CaChi19A_CatD consisting of two ChBDs and a catalytic domain, one ChBD and a catalytic domain, and only a catalytic domain, respectively. CaChi19A, CaChi19A_ΔI, CaChi19A_ΔIΔII, and CaChi19A_CatD exhibited cold adaptation, as their relative enzyme activities at 5 °C were 40.7, 51.6, 66.2, and 82.6%, respectively. Compared with CaChi19A and other variants, CaChi19A_ΔIΔII demonstrated a higher level of stability below 50 °C and retained relatively high activity over a wide pH range of 5-12. Analysis of the hydrolysis products revealed that CaChi19A and CaChi19A_ΔIΔII exhibit exoacting, endoacting, and N-acetyl-ß-d-glucosaminidase activities toward colloidal chitin. Furthermore, CaChi19A and CaChi19A_ΔIΔII exhibited inhibitory effects on the hyphal growth of Fusarium oxysporum, Fusarium redolens, Fusarium fujikuroi, Fusarium solani, and Coniothyrium diplodiella, thereby illustrating effective biocontrol activity. These results indicated that CaChi19A and CaChi19A_ΔIΔII show advantages in some applications where low temperatures were demanded in industries as well as the biocontrol of fungal diseases in agriculture.
Assuntos
Quitina , Quitinases , Temperatura Baixa , Proteínas Fúngicas , Fusarium , Doenças das Plantas , Quitinases/genética , Quitinases/química , Quitinases/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/química , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Quitina/metabolismo , Quitina/química , Fusarium/enzimologia , Fusarium/genética , Fusarium/metabolismo , Estabilidade EnzimáticaRESUMO
Maize chitinases are involved in chitin hydrolysis. Chitinases are distributed across various organisms including animals, plants, and fungi and are grouped into different glycosyl hydrolase families and classes, depending on protein structure. However, many chitinase functions and their interactions with other plant proteins remain unknown. The economic importance of maize (Zea mays L.) makes it relevant for studying the function of plant chitinases and their biological roles. This work aims to identify chitinase genes in the maize genome to study their gene structure, family/class classification, cis-related elements, and gene expression under biotic stress, such as Fusarium verticillioides infection. Thirty-nine chitinase genes were identified and found to be distributed in three glycosyl hydrolase (GH) families (18, 19 and 20). Likewise, the conserved domains and motifs were identified in each GH family member. The identified cis-regulatory elements are involved in plant development, hormone response, defense, and abiotic stress response. Chitinase protein-interaction network analysis predicted that they interact mainly with cell wall proteins. qRT-PCR analysis confirmed in silico data showing that ten different maize chitinase genes are induced in the presence of F. verticillioides, and that they could have several roles in pathogen infection depending on chitinase structure and cell wall localization.