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.

Induction of systemic resistance in rice against sheath blight disease by Pseudomonas fluorescens

Abstract: Two Pseudomonas fluorescens strains viz., PF1 and FP7 which inhibited the mycelial growth of sheath blight fungus Rhizoctonia solani and increased the seedling vigour of rice plants in vitro were selected for assessing induced systemic resistance (ISR) against R. solani in rice. The Pseudomonas application as a bacterial suspension or a talc-based formulation through seed, root, soil and foliar application either alone or in combination (seed+root+soil+foliar) effectively reduced sheath blight disease incidence, promoted plant growth and ultimately increased yields under glasshouse or field conditions. Efficacy of Pseudomonas strains against R. solani was comparable to that of the fungicide carbendazim, which is normally used in the field to manage the disease. Pseudomonas treatment of rice cv IR50 led to induction of systemic resistance against R. solani , as a result of increase in chitinase and peroxidase activity. However, the extent of increase varied between treatments, Pseudomonas strains used and their duration. Though two chitinase isoforms (35 and 28 kDa) and five peroxidase isozymes (PO1–PO5) were found to be associated with the ISR, 35 kDa chitinase and three peroxidase isozymes (PO3–PO5) were established as the major determinants of ISR. Although a single application of a Pseudomonas strain resulted in ISR, the combined application through all of the four (seed, root, soil and foliar) methods increased the durability of ISR in rice plants. In addition, the Pseudomonas strains produced chitinase in the culture medium. It is presumed that the induced chitinase, peroxidase and bacterial chitinase may be either directly or indirectly involved in the reduction of sheath blight disease development in rice.

Isolation and Characterization of the Genes Encoding Basic and Acidic Chitinase in Arabidopsis thaliana.

Abstract: Plants synthesize a number of antimicrobial proteins in response to pathogen invasion and environmental stresses. These proteins include two classes of chitinases that have either basic or acidic isoelectric points and that are capable of degrading fungal cell wall chitin. We have cloned and determined the nucleotide sequence of the genes encoding the acidic and basic chitinases from Arabidopsis thaliana (L.) Heynh. Columbia wild type. Both chitinases are encoded by single copy genes that contain introns, a novel feature in chitinase genes. The basic chitinase has 73% amino acid sequence similarity to the basic chitinase from tobacco, and the acidic chitinase has 60% amino acid sequence similarity to the acidic chitinase from cucumber. Expression of the basic chitinase is organ-specific and age-dependent in Arabidopsis. A high constitutive level of expression was observed in roots with lower levels in leaves and flowering shoots. Exposure of plants to ethylene induced high levels of systemic expression of basic chitinase with expression increasing with plant age. Constitutive expression of basic chitinase was observed in roots of the ethylene insensitive mutant (etr) of Arabidopsis, demonstrating that root-specific expression is ethylene independent. Expression of the acidic chitinase gene was not observed in normal, untreated Arabidopsis plants or in plants treated with ethylene or salicylate. However, a transient expression assay indicated that the acidic chitinase promoter is active in Arabidopsis leaf tissue.

Antifungal Hydrolases in Pea Tissue: I. Purification and Characterization of Two Chitinases and Two β-1,3-Glucanases Differentially Regulated during Development and in Response to Fungal Infection

Abstract: Chitinase and β-1,-3-glucanase activities increased coordinately in pea (Pisum sativum L. cv “Dot”) pods during development and maturation and when immature pea pods were inoculated with compatible or incompatible strains of Fusarium solani or wounded or treated with chitosan or ethylene. Up to five major soluble, basic proteins accumulated in stressed immature pods and in maturing untreated pods. After separation of these proteins by chromatofocusing, an enzymic function could be assigned to four of them: two were chitinases and two were β-1,3-glucanases. The different molecular forms of chitinase and β-1,3-glucanase were differentially regulated. Chitinase Ch1 (mol wt 33,100) and β-1,3-glucanase G2 (mol wt 34,300) were strongly induced in immature tissue in response to the various stresses, while chitinase Ch2 (mol wt 36,200) and β-1,3-glucanase G1 (mol wt 33,500) accumulated during the course of maturation. With a simple, three-step procedure, both chitinases and both β-1,3-glucanases were purified to homogeneity from the same extract. The two chitinases were endochitinases. They differed in their pH optimum, in specific activity, in the pattern of products formed from [3H]chitin, as well as in their relative lysozyme activity. Similarly, the two β-1,3-glucanases were endoglucanases that showed differences in their pH optimum, specific activity, and pattern of products released from laminarin.

Genetic Engineering of Rice for Resistance to Sheath Blight

Abstract: A 1.1 kb rice genomic DNA fragment, containing a chitinase gene under the control of the CaMV 35S promoter, was cloned into the rice transformation vector pGL2. After transformation of Indica rice protoplasts in the presence of polyethyleneglycol, plants were regenerated. The presence of the chimeric chitinase gene in T0 and T1 transgenic rice plants was detected by Southern blot analysis. Western blot analysis of transgenic plants and their progeny revealed the presence of two proteins with apparent molecular weights of 30 and 35 kDa that reacted with the chitinase antibody. Progeny from the chitinase-positive plants were tested for their resistance to the sheath blight pathogen, Rhizoctonia solani. The degree of resistance displayed by the transgenic plants to this pathogen correlated with the level of chitinase expression.

Synergistic activity of chitinases and β-1,3-glucanases enhances fungal resistance in transgenic tomato plants

Abstract: Simultaneous expression of a tobacco class I chitinase and a class I β-1,3-glucanase gene in tomato resulted in increased fungal resistance, whereas transgenic tomato plants expressing either one of these genes were not protected against fungal infection After infection with Fusarium oxysporum fsp lycopersici, a 36% to 58% reduction in disease severity was observed in resistant tomato lines Two transgenic lines largely recovered from the initial infection by the time wild-type tomato plants had died