Showing papers on "Chitinase published in 2017"
19 Jul 2017
TL;DR: Chitinolytic microorganisms are likely to play an important role as biocontrol agents and pathogen antagonists and may also function in the control of postharvest rot.
Abstract: Chitin is an important component of the exteriors of insects and fungi. Upon degradation of chitin by a number of organisms, severe damage and even death may occur in pathogens and pests whose external surfaces contain this polymer. Currently, chemical fungicides and insecticides are the major means of controlling these disease-causing agents. However, due to the potential harm that these chemicals cause to the environment and to human and animal health, new strategies are being developed to replace or reduce the use of fungal- and pest-killing compounds in agriculture. In this context, chitinolytic microorganisms are likely to play an important role as biocontrol agents and pathogen antagonists and may also function in the control of postharvest rot. In this review, we discuss the literature concerning chitin and the basic knowledge of chitin-degrading enzymes, and also describe the biocontrol effects of chitinolytic microorganisms and their potential use as more sustainable pesticides and fungicides in the field.
116 citations
TL;DR: It is suggested that altered chitin clearance could exacerbate fibrogenic pathways in the setting of lung diseases characterized by epithelial cell dysfunction, particularly in mice with lung fibrosis due to telomere dysfunction and humans with interstitial lung disease.
86 citations
01 Jan 2017
TL;DR: This review focuses on the different aspects of various hydrolytic enzymes produced by rhizoflora and their role in sustainable biocontrol of phytopathogens.
Abstract: Microbial community in the rhizosphere produces a variety of hydrolytic enzymes that are responsible for the degradation of various components of fungal pathogens. The extracellular hydrolytic enzymes excreted by soil rhizobia degrade cell wall components of plant pathogenic microbes. The enzymes of these types are able to breakdown glycosidic linkages present in the polysaccharide of the cell wall of phytopathogens. In this regard, plant growth-promoting rhizobacteria (PGPR) are known to colonize rhizosphere and enhance plant growth through different mechanisms that include (i) plant growth promotion and (ii) biological control of plant disease. Plant growth promotion mechanisms include mineralization of insoluble substances, production of plant growth hormones, biological nitrogen fixation, and promotion of root growth. Biocontrol mechanism involves competition, antibiosis, parasitism, induction of systemic acquired resistance (SAR), induction of systemic resistance (ISR), soil suppressiveness, and production of various antifungal metabolites; hydrolytic enzymes such as chitinase, glucanase, protease, and cellulase; and antibiotics such as 2,4-diacetyl phloroglucinol (DAPG), amphisin, oomycin A, hydrogen cyanide, phenazine, pyoluteorin, pyrrolnitrin, cyclic lipopeptides, oligomycin A, zwittermicin A, kanosamine, and xanthobaccin. Production of hydrolytic enzymes by PGPR is an important mechanism directed against phytopathogens for sustainable plant disease management. These enzymes break down the cell wall of fungal pathogens causing cell death. This review focuses on the different aspects of various hydrolytic enzymes produced by rhizoflora and their role in sustainable biocontrol of phytopathogens.
85 citations
TL;DR: An efficient conversion of chitin, the second most abundant renewable polymer on the Earth, into N-acetylglucosamine and N,N′-diacetylchitobiose, using room temperature ionic liquids (RTILs) and commercially available chit inases is described for the first time.
75 citations
TL;DR: This critical review discusses the complex nexus of chit in and chitinase and assesses both their pathogenic as well as utilitarian aspects.
69 citations
TL;DR: Crystal structures of both OfChi-h and its complex with chitoheptaose reveal that OfCha-h possesses a long and asymmetric substrate binding cleft, which is a typical characteristics of a processive exo-chitinase.
58 citations
TL;DR: Five endophytic Bacillus spp.
51 citations
TL;DR: The results indicate that the chickpea defense pathway is triggered after perception of endophytes to synthesize various enzymes, which led to an induced resistance against S. rolfsii.
50 citations
TL;DR: Functional similarity of chicken Chia with the mouse enzyme suggests that chitin-containing organisms can be used for alternative poultry diets not only as whole edible resources but also as enhancers of their nutritional value.
Abstract: Chitin, a polymer of N-acetyl-D-glucosamine (GlcNAc), functions as a major structural component in crustaceans, insects and fungi and is the second most abundant polysaccharide in the nature. Although these chitin-containing organisms have been suggested as novel animal feed resources, chitin has long been considered as indigestible fibers in the animal body. Recently, we reported that acidic chitinase (Chia) is a protease-resistant major glycosidase in mouse gastrointestinal tract (GIT) and that it digests chitin in the mouse stomach. However, the physiological role of Chia in other animals including poultry remains unknown. Here, we report that Chia can function as a digestive enzyme that breaks down chitin-containing organisms in chicken GIT. Chia mRNA is predominantly expressed in the glandular stomach tissue in normal chicken. We also show that chicken Chia has a robust chitinolytic activity at pH 2.0 and is highly resistant to proteolysis by pepsin and trypsin/chymotrypsin under conditions mimicking GIT. Chia degraded shells of mealworm larvae in the presence of digestive proteases and produced (GlcNAc)2. Thus, functional similarity of chicken Chia with the mouse enzyme suggests that chitin-containing organisms can be used for alternative poultry diets not only as whole edible resources but also as enhancers of their nutritional value.
48 citations
TL;DR: The interaction study between antagonist strain and fungal pathogen revealed that the actinobacterium was able to damage fungal mycelia may be due to chitinase, establishing its role as a potential antagonist against M. phaseolina.
46 citations
TL;DR: Thin layer chromatography revealed that enzyme can effectively hydrolyze colloidal chitin to produce chitooligosaccharides and was found to be significant and statistical analysis of results showed that an appropriate ratio of chitIn and colloidal Chitin had resulted into enhancement in enzyme production levels.
TL;DR: The novel chitinase gene cloned and characterized in the present study from the QTL region of rice will be of significant use in molecular plant breeding program for developing sheath blight resistance in rice.
Abstract: Sheath blight disease (ShB), caused by the fungus Rhizoctonia solani Kuhn, is one of the most destructive diseases of rice (Oryza sativa L.), causing substantial yield loss in rice. In the present study, a novel rice chitinase gene, LOC_Os11g47510 was cloned from QTL region of R. solani tolerant rice line Tetep and used for functional validation by genetic transformation of ShB susceptible japonica rice line Taipei 309 (TP309). The transformants were characterized using molecular and functional approaches. Molecular analysis by PCR using a set of primers specific to CaMv 35S promoter, chitinase and HptII genes confirmed the presence of transgene in transgenic plants which was further validated by Southern hybridization. Further, qRT-PCR analysis of transgenic plants showed good correlation between transgene expression and the level of sheath blight resistance among transformants. Functional complementation assays confirmed the effectiveness of the chitinase mediated resistance in all the transgenic TP309 plants with varying levels of enhanced resistance against R. solani. Therefore, the novel chitinase gene cloned and characterized in the present study from the QTL region of rice will be of significant use in molecular plant breeding program for developing sheath blight resistance in rice.
TL;DR: Injection and feeding experiments demonstrated that phlegmacin B1 has insecticidal effect on O. furnacalis's larvae and provides an example of exploiting microbial secondary metabolites as potential pest control and management agents.
Abstract: Periodic chitin remodeling during insect growth and development requires a synergistic action of two glycosyl hydrolase (GH) family enzymes, GH18 chitinase and GH20 β-N-acetylhexosaminidase (Hex). Inhibiting either or both of these enzymes is a promising strategy for pest control and management. In this study, OfChi-h (a GH18 chitinase) and OfHex1 (a GH20 Hex) from Ostrinia furnacalis were used to screen a library of microbial secondary metabolites. Phlegmacin B1 was found to be the inhibitor of both OfChi-h and OfHex1 with Ki values of 5.5 μM and 26 μM, respectively. Injection and feeding experiments demonstrated that phlegmacin B1 has insecticidal effect on O. furnacalis’s larvae. Phlegmacin B1 was predicted to bind to the active pockets of both OfChi-h and OfHex1. Phlegmacin B1 also showed moderate inhibitory activities against other bacterial and insect GH18 enzymes. This work provides an example of exploiting microbial secondary metabolites as potential pest control and management agents.
TL;DR: This is the first report of high chitinase yielding Bacillus pumilus strain from mangrove ecosystem with a biocontrol role against phytopathogenic fungi and insect larval pests.
TL;DR: It is shown that Cht2 is expressed in the chitin-matrix of epidermis, trachea, and the digestive system, and that in ChT2 knockdown larvae the assembly zone is rudimentary, preventing normal cuticle formation and pore canal organization.
TL;DR: Enhanced activation of defense-related activities in plants upon priming with SA suggests that it alters plant physiology which in turn is useful for production and protection of brinjal.
TL;DR: Reactive oxygen species (ROS) scavenging enzymes activity analysis showed that the activities of peroxidase (POD), polyphenol oxidase (PPO) and superoxide dismutase (SOD) increased significantly in T- soybean pretreated plants, suggesting that T-soybean treatment induced resistance in soybean seedlings to F. oxysporum.
TL;DR: It is suggested that ChiIV3 acts as a likely antifungal protein and as a receptor for unidentified chitin in planta to trigger cell death and defense signaling against PCI.
Abstract: Despite the involvement of many members of the chitinase family in plant immunity, the precise functions of the majority of the members remain poorly understood. Herein, the gene ChiIV3 in Capsicum annuum encoding a chitinase protein containing a chitin binding domain and targeting to the plasma membrane was found to be induced by Phytophthora capsici inoculation (PCI) and applied chitin treatment. Besides its direct inhibitory effect on growth of Phytophthora capsici (P. capsici), ChiIV3 was also found by virus-induced gene silencing (VIGS) and transient overexpression (TOE) in pepper plants to act as a positive regulator of plant cell death and in triggering defense signaling and upregulation of PR (pathogenesis related) genes against PCI. A 5' deletion assay revealed that pChiIV3-712 to -459 bp was found to be sufficient for ChiIV3' response to PCI. Furthermore, a mutation assay indicated that W-box-466 to -461 bp in pChiIV3-712 to -459 bp was noted to be the PCI-responsible element. These results collectively suggest that ChiIV3 acts as a likely antifungal protein and as a receptor for unidentified chitin in planta to trigger cell death and defense signaling against PCI.
TL;DR: Transglycosylation by EcChi1 on trimeric to hexameric CHOS resulted in the formation of longer CHOS for a prolonged duration, and homology modeling and docking with CHOS suggested that Ec Chi1 has a deep substrate-binding groove lined with aromatic amino acids, which is a characteristic feature of a processive enzyme.
Abstract: Humans have exploited natural resources for a variety of applications. Chitin and its derivative chitin oligosaccharides (CHOS) have potential biomedical and agricultural applications. Availability of CHOS with the desired length has been a major limitation in the optimum use of such natural resources. Here, we report a single domain hyper-transglycosylating chitinase, which generates longer CHOS, from Enterobacter cloacae subsp. cloacae 13047 (EcChi1). EcChi1 was optimally active at pH 5.0 and 40 °C with a Km of 15.2 mg ml−1, and k
cat/Km of 0.011× 102 mg−1 ml min−1 on colloidal chitin. The profile of the hydrolytic products, major product being chitobiose, released from CHOS indicated that EcChi1 was an endo-acting enzyme. Transglycosylation (TG) by EcChi1 on trimeric to hexameric CHOS resulted in the formation of longer CHOS for a prolonged duration. EcChi1 showed both chitobiase and TG activities, in addition to hydrolytic activity. The TG by EcChi1 was dependent, to some extent, on the length of the CHOS substrate and concentration of the enzyme. Homology modeling and docking with CHOS suggested that EcChi1 has a deep substrate-binding groove lined with aromatic amino acids, which is a characteristic feature of a processive enzyme.
TL;DR: expression of chitinase gene was studied by RT-PCR in response to Alternaria brassicae and shows the tissue specificity of the gene, which will help in using this promoter discretely in developing fungus resistant transgenic plants.
TL;DR: This study systematically dissects the contribution of each gene to growth on chitin as well as induction of natural transformation in Vibrio cholerae, and finds that low levels of chit inase activity are sufficient for natural transformation, while growth on insoluble ch itin as a sole carbon source requires more robust and concerted chitInase activity.
Abstract: Vibrio cholerae is a natural resident of the aquatic environment, where a common nutrient is the chitinous exoskeletons of microscopic crustaceans. Chitin utilization requires chitinases, which degrade this insoluble polymer into soluble chitin oligosaccharides. These oligosaccharides also serve as an inducing cue for natural transformation in Vibrio species. There are 7 predicted endochitinase-like genes in the V. cholerae genome. Here, we systematically dissect the contribution of each gene to growth on chitin as well as induction of natural transformation. Specifically, we created a strain that lacks all 7 putative chitinases and from this strain, generated a panel of strains where each expresses a single chitinase. We also generated expression plasmids to ectopically express all 7 chitinases in our chitinase deficient strain. Through this analysis, we found that low levels of chitinase activity are sufficient for natural transformation, while growth on insoluble chitin as a sole carbon source requires more robust and concerted chitinase activity. We also assessed the role that the three uptake systems for the chitin degradation products GlcNAc, (GlcNAc)2 and (GlcN)2 , play in chitin utilization and competence induction. Cumulatively, this study provides mechanistic details for how this pathogen utilizes chitin to thrive and evolve in its environmental reservoir.
TL;DR: Results indicate that the extracellular chitinase produced by P. elgii HOA73 might have function in limiting spore germination of certain fungal pathogens.
Abstract: Chitinase-producing Paenibacillus elgii strain HOA73 has been used to control plant diseases. However, the antimicrobial activity of its extracellular chitinase has not been fully elucidated. The major extracellular chitinase gene (PeChi68) from strain HOA73 was cloned and expressed in Escherichia coli in this study. This gene had an open reading frame of 2,028 bp, encoding a protein of 675 amino acid residues containing a secretion signal peptide, a chitin-binding domain, two fibronectin type III domains, and a catalytic hydrolase domain. The chitinase (PeChi68) purified from recombinant E. coli exhibited a molecular mass of approximately 68 kDa on SDS-PAGE. Biochemical analysis indicated that optimum temperature for the actitvity of purified chitinase was 50oC. However, it was inactivated with time when it was incubated at 40oC and 50oC. Its optimum activity was found at pH 7, although its activity was stable when incubated between pH 3 and pH 11. Heavy metals inhibited this chitinase. This purified chitinase completely inhibited spore germination of two Cladosporium isolates and partially inhibited germination of Botrytis cinerea spores. However, it had no effect on the spores of a Colletotricum isolate. These results indicate that the extracellular chitinase produced by P. elgii HOA73 might have function in limiting spore germination of certain fungal pathogens.
TL;DR: In this article, an experiment was conducted in the field of National Institute of Agronomic Research of Meknes, Morocco, where a total of three different bacteria colonies were isolated and proceed with in vitro screening for plant growth promoting activities; phosphate solubilization, nitrogen fixation, indole acetic acid (IAA), ammonia production and antimicrobial enzymes (cellulose, chitinase and protease) activity.
Abstract: Plant Growth promoting rhizobacteria are a heterogeneous group of bacteria that can be found in the rhizosphere, at root surfaces and in association with roots. They benefit plants through Production of plant hormones, such as auxins, asymbiotic N2 fixation, solubilization of mineral phosphates, antagonism against phytopathogenic microorganisms by production of antibiotics, siderophroes, Chitinase and other nutrients ability to effectively colonize roots are responsible for plant growth promotion. An experiment was conducted in the field of National Institute of Agronomic Research of Meknes. Morocco. The experiment was a completely randomized design with six replicates. There were four treatments viz. T1: (control; N0 -PGPR), T2: (N0 +2027-2), T3: (N0 +2066-7) and T4: (N0+2025-1). The results indicated that a remarkable increase in root growth, namely length, the diameter of the rod and the total chlorophyll. A total of three different bacteria colonies were isolated and proceed with in vitro screening for plant growth promoting activities; phosphate solubilization, nitrogen fixation, indole acetic acid (IAA), ammonia production and antimicrobial enzymes (cellulose, chitinase and protease) activity. Among the three bacterial strains, all bacterial strains are able to produce ammonia, IAA production and nitrogen fixation activity, one strain phosphate solubilizing activity, two strain are able to produce cellulase syntheses, Protease activity and Chitinase activity.
01 Jan 2017
TL;DR: The current chapter aims to identify the sources, kinds of enzymes, and the perspectives for further studies in their application in endophytic-based extracellular enzymes resources.
Abstract: Endophytes (fungi and bacteria) have been known to live asymptomatically with plants throughout the different growth and developmental stages. Endophytic microbes provide an additional resource to the plant due to the presence of beneficial secondary metabolites, enzymes, and nutrients, which help the host to combat diverse arrays of stressful conditions of biotic and abiotic stresses. Extracellular enzymes are the product of microbial’s cell growth and perform its function outside the cell in many biological or environmental processes. In fact, certain category of enzymes namely, xylanases, hemicellulases, phytases, proteases, asparaginase, cellulases, pectinases, tyrosinase, gelatinase, chitinase, amylases, etc., are some of the key enzymes produced by endophytic bacteria and fungi. Most of these enzymes have been reported from endophytes living within medicinal or crop plants, whereas they are detected through agar-based methods. The current chapter aims to identify the sources, kinds of enzymes, and the perspectives for further studies in their application in endophytic-based extracellular enzymes resources.
TL;DR: In the field evaluation, application of both S. griseorubens E44G treatments significantly increased all tested growth and yield parameters and decreased the disease severity compared with the infected-untreated tomato plants suggesting potential as a biocontrol agent.
Abstract: Streptomyces griseorubens E44G is a chitinolytic bacterium isolated from cultivated soil in Saudi Arabia (a hot, arid climatic region). In vitro, antifungal potential of S. griseorubens E44G was assessed against the phytopathogenic fungus, Fusarium oxysporum f. sp. lycopersici (the causative agent of the Fusarium wilt disease of tomato). An inhibition zone of 24 mm was recorded. The chitinolytic activity of S. griseorubens E44G was proved when the colloidal chitin agar plate method was used. A thermostable chitinase enzyme of 45 kDa molecular weight was purified using gel filtration chromatography. The optimum activity was obtained at 60 °C and pH 5.5. The purified enzyme has shown a very pronounced activity against the phytopathogenic fungus, F. oxysporum. The molecular characterization of the chitinase gene indicated that it consists of 1218 bp encoding 407 amino acids. The phylogentic analysis based on the nucleotide DNA sequence and the deduced amino acids sequence showed high similarity percentages with other chitinases isolated from different Streptomyces species. In the field evaluation, application of both S. griseorubens E44G treatments significantly increased all tested growth and yield parameters and decreased the disease severity compared with the infected-untreated tomato plants suggesting potential as a biocontrol agent.
TL;DR: It is suggested that soil microbes aid in sustainable bioconversion of lobster shells and extraction of chitin derivatives that could be applied in plant protection.
Abstract: Biodegradation of lobster shells by chitinolytic microorganisms are an environment safe approach to utilize lobster processing wastes for chitin derivation. In this study, we report degradation activities of two microbes, “S223” and “S224” isolated from soil samples that had the highest rate of deproteinization, demineralization and chitinolysis among ten microorganisms screened. Isolates S223 and S224 had 27.3 and 103.8 protease units.mg-1 protein and 12.3 g.ml-1 and 11.2 g.ml-1 of calcium in their samples, respectively after one week of incubation with raw lobster shells. Further, S223 contained 23.8 g.ml-1 of N-Acetylglucosamine on day three, while S224 had 27.3 g.ml-1 on day seven of incubation with chitin. Morphological observations and 16S rDNA sequencing suggested both the isolates were Streptomyces. The culture conditions were optimized for efficient degradation of lobster shells and chitinase (~30 kDa) was purified from crude extract by affinity chromatography. The digested lobster shell extracts induced disease resistance in Arabidopsis by induction of defense related genes (PR1 > 500 fold, PDF1.2 > 40 fold) upon Pseudomonas syringae and Botrytis cinerea infection. The study suggests that soil microbes aid in sustainable bioconversion of lobster shells and extraction of chitin derivatives that could be applied in plant protection.
TL;DR: Using label-free quantification (LFQ) proteomics and a recently developed plate-method for assessing secretomes during growth on solid substrates, it is found that, as expected, the chitin-active enzymes (ChiA, B, C, and CBP21) are produced in high amounts when the bacterium grows on Chitin.
TL;DR: In this paper, the ability of Bacillus subtilis, strain ALICA to produce three mycolytic enzymes (chitinase, β-1,3-glucanase, and protease), was carried out by the chemical standard methods.
Abstract: The ability of Bacillus subtilis, strain ALICA to produce three mycolytic enzymes (chitinase, β-1,3-glucanase, and protease), was carried out by the chemical standard methods. Bacillus subtilis ALICA was screened based on their antifungal activity in dual plate assay and cell-free culture filtrate (25%) against five different phytopathogenic fungi Alternaria alternata, Macrophomina sp., Colletotrichum gloeosporioides, Botrytis cinerea, and Sclerotium rolfesii. The B. subtilis ALICA detected positive for chitinase, β-1,3-glucanase and protease enzymes. Fungal growth inhibition by both strain ALICA and its cell-free culture filtrate ranged from 51.36% to 86.3% and 38.43% to 68.6%, respectively. Moreover, hyphal morphological changes like damage, broken, swelling, distortions abnormal morphology were observed. Genes expression of protease, β-1,3-glucanase, and lipopeptides (subtilosin and subtilisin) were confirmed their presence in the supernatant of strain ALICA. Our findings indicated that strain ALICA provided a broad spectrum of antifungal activities against various phytopathogenic fungi and may be a potential effective alternative to chemical fungicides.
TL;DR: A role for the bacterial isolate Bacillus sp.
Abstract: In the present research, bacterial-mediated elicitation of induced systemic resistance in the soybean plant was studied. The main objective was in vitro analysis of jasmonic acid and different defense-related enzymes in soybean plants primed with bacterium Bacillus sp. SJ-5 against the fungal pathogen Rhizoctonia solani and Fusarium oxysporum. In the different assays conducted, Bacillus sp. SJ-5 showed strong antifungal activity against R. solani and F. oxysporum showing 45 and 63 % growth inhibition, respectively. Strain SJ-5 was found to be positive for the cell wall-degrading enzymes chitinase, protease, and β-1,3-glucanase, and cell-free supernatant was found with significant fungal growth inhibitory activity. Different defense-related enzymes, namely lipoxygenase, phenylalanine ammonia-lyase, peroxidase, polyphenol oxidase, and β-1,3-glucanase in the different parts of Glycine max L. Merrill were reported to be highest on the 8th day after challenge inoculation and expressed significantly in the root tissue. GC–MS analysis of jasmonic acid (JA) revealed the highest JA accumulation in bacterized soybean plant root tissue challenged with R. solani and F. oxysporum, which was 91.2 and 99.84 %, respectively, with respect to control. In the SJ-5-primed root tissue, phenolic content was highest upon challenge inoculation of R. solani and F. oxysporum with 30.47 ± 0.97 and 32.4 ± 0.3 mg/g fresh weight, respectively. In summary, the present investigation revealed a role for the bacterial isolate Bacillus sp. SJ-5 in soybean plant growth promotion and enhanced protection against R. solani and F. oxysporum by elicitation of defense-related enzymes.