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Chitinase

About: Chitinase is a research topic. Over the lifetime, 4690 publications have been published within this topic receiving 161786 citations. The topic is also known as: 1,4-beta-poly-N-acetylglucosaminidase & poly-beta-glucosaminidase.


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Journal ArticleDOI
TL;DR: Constitutive expression of the following acidic isoforms of tobacco PRs did not affect the time course or the final level of colonization by the vesicular-arbuscular mycorrhizal fungus Glomus mosseae: PR-1a, PR-3 (=PR-Q), PR-Q(prm1),PR-4, and PR-5.
Abstract: We studied the effect of constitutive expression of pathogenesis-related proteins (PRs) in tobacco plants on vesicular-arbuscular mycorrhiza. Tobacco lines genetically transformed to express various PRs constitutively under the control of the cauliflower mosaic virus 35S promoter of tobacco were examined. Immunoblot analysis and activity measurements demonstrated high levels of expression of the PRs in the root systems of the plants. Constitutive expression of the following acidic isoforms of tobacco PRs did not affect the time course or the final level of colonization by the vesicular-arbuscular mycorrhizal fungus Glomus mosseae: PR-1a, PR-3 (=PR-Q), PR-Q(prm1), PR-4, and PR-5. Similarly, constitutive expression of an acidic cucumber chitinase, of a basic tobacco chitinase with and without its vacuolar targeting peptide, of a basic (beta)-1,3-glucanase, and of combinations of PR-Q and PR-Q(prm1) or basic chitinase and basic (beta)-1,3-glucanase did not affect colonization by the mycorrhizal fungus. A delay of colonization by G. mosseae was observed in tobacco plants constitutively expressing the acidic isoform of tobacco PR-2, a protein with (beta)-1,3-glucanase activity.

126 citations

Journal ArticleDOI
TL;DR: The introduction of disease defence genes into rose provides a method of producing blackspot-resistant rose cultivars sought by breeders and growers.
Abstract: Blackspot, caused by the Ascomycete fungus Diplocarpon rosae, is the most widespread and pernicious disease of cultivated roses. While some species of rose possess resistance to D. rosae, none of the modern-day rose cultivars are fully resistant to the pathogen. In the current study, Biolistic gene delivery was used to introduce a rice gene, encoding a basic (Class I), chitinase into embryogenic callus of the blackspot-susceptible rose (Rosa hybrida L.) cv. Glad Tidings. The plasmid used for transformation carried the neomycin phosphotransferase (nptII) gene facilitating the selection and regeneration of transgenic plants on medium containing 250 mg/l kanamycin. Southern analysis confirmed integration of 2–6 copies of the chitinase gene into the rose genome; gene expression was confirmed by enzyme assay. Bioassays demonstrated that expression of the chitinase transgene reduced the severity of blackspot development by 13–43%. This degree of resistance to the pathogen correlated with the level of chitinase expression in the transgenic rose plants. The introduction of disease defence genes into rose provides a method of producing blackspot-resistant rose cultivars sought by breeders and growers.

126 citations

Journal ArticleDOI
01 Aug 1990-Planta
TL;DR: It is concluded that ethylene changes the cell-type-specific distribution but not the intracellular compartmentation of the two enzymes, which support the generalization that basic isoforms of chitinase and β-1,3-glucanase are intrACEllular whereas the acidic isoforms are secreted into the extracellular space.
Abstract: We have studied the effect of ethylene on the localization of the basic isoforms of glucan endo-1,3-β-glucosidase (β-1,3-glucanase, EC 3.2.1.39) and endo-chitinase (chitinase, EC 3.2.1.14) in leaves of Nicotiana tabacum L. cv. Havana 425. Comparisons of the enzyme contents of the lower epidermis of the leaf, leaf expiants with the lower epidermis removed, and intercellular wash fluid indicate that both enzymes are localized inside epidermal cells of untreated leaves. Ethylene treatment (20 μl·l-1, 4d) induced a marked -10- to 30-fold-coordinated accumulation of the enzymes. This was due primarily to induction of the basic isoforms inside chlorenchyma cells of the leaf interior. The localization of basic β-1,3-glucanase was confirmed by immunofluorescence histochemistry and immunogold cytochemistry. Immunolabelling was confined to electron-dense bodies of the cell vacuole. No extracellular immunolabelling was detected in control or ethylene-treated leaves. We conclude that ethylene changes the cell-type-specific distribution but not the intracellular compartmentation of the two enzymes. These results support the generalization that basic isoforms of chitinase and β-1,3-glucanase are intracellular whereas the acidic isoforms are secreted into the extracellular space.

126 citations

Journal ArticleDOI
TL;DR: The data indicate that nag1 is essential for triggering chitinase gene expression in T. atroviride and that its functional impairment reduces biocontrol by T.Atrovirid by a significant extent.
Abstract: The nag1 gene of the mycoparasitic fungus Trichoderma atroviride encodes a 73-kDa N-acetyl-β-d-glucosaminidase, which is secreted into the medium and partially bound to the cell wall. To elucidate the role of this enzyme in chitinase induction and biocontrol, a nag1-disruption mutant was prepared. It displayed only 4% of the original N-acetyl-β-d-glucosaminidase activity, indicating that the nag1 gene product accounts for the majority of this activity in T. atroviride. The nag1-disruption strain was indistinguishable from the parent strain in growth and morphology, but exhibited delayed autolysis. Northern analysis showed that colloidal chitin disruption does not induce ech42 gene transcription in the nag1-disruption strain. Enzyme activities capable of hydrolysing p-nitrophenyl-N,N′-diacetylchitobioside and p-nitrophenyl-N,N′-diacetylchitotriose were also absent from the nag1-disruption strain under the same conditions. Retransformation of the T. atroviride nag1-disruption strain with the nag1 gene essentially led to the parent-type behaviour in all these experiments. However, addition of N-acetyl-β-d-glucosaminidase to the medium of the nag1-disruption strain did not rescue the mutant phenotype. The disruption-nag1 strain showed 30% reduced ability to protect beans against infection by Rhizoctonia solani and Sclerotinia sclerotiorum. The data indicate that nag1 is essential for triggering chitinase gene expression in T. atroviride and that its functional impairment reduces biocontrol by T. atroviride by a significant extent.

125 citations

Journal ArticleDOI
TL;DR: Chitinases can have housekeeping function in plasticizing the cell wall or can act more specifically during cell separation, nutritional chitin acquisition, or competitive interaction with other fungi.
Abstract: In the past decades our knowledge about fungal cell wall architecture increased tremendously and led to the identification of many enzymes involved in polysaccharide synthesis and remodeling, which are also of biotechnological interest. Fungal cell walls play an important role in conferring mechanic stability during cell division and polar growth. Additionally, in phytopathogenic fungi the cell wall is the first structure that gets into intimate contact with the host plant. A major constituent of fungal cell walls is chitin, a homopolymer of N-acetylglucosamine units. To ensure plasticity, polymeric chitin needs continuous remodeling which is maintained by chitinolytic enzymes, including lytic polysaccharide monooxygenases N-acetylglucosaminidases, and chitinases. Depending on the species and lifestyle of fungi, there is great variation in the number of encoded chitinases and their function. Chitinases can have housekeeping function in plasticizing the cell wall or can act more specifically during cell separation, nutritional chitin acquisition, or competitive interaction with other fungi. Although chitinase research made huge progress in the last decades, our knowledge about their role in phytopathogenic fungi is still scarce. Recent findings in the dimorphic basidiomycete Ustilago maydis show that chitinases play different physiological functions throughout the life cycle and raise questions about their role during plant-fungus interactions. In this work we summarize these functions, mechanisms of chitinase regulation and their putative role during pathogen/host interactions.

125 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023186
2022337
2021148
2020172
2019154
2018152