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.

Chitinase production by endophytic Streptomyces aureofaciens CMUAc130 and its antagonism against phytopathogenic fungi

Abstract: More than three hundred isolates of endophytic actinomycetes were screened for their potential for chitinase production. The strain identified as Streptomyces aureofaciens CMUAc130 was the most effective amongst those investigated. This isolate was selected for a more detailed study of chitinase production and its effectiveness in fungal cell wall lysis. Production of the chitinase was optimal with 1% colloidal chitin concentration, at 30-40 °C, pH 6.5-7.0 and 100-150 rev min -1 shaking. N-acetylglucosamine was a good inducer and expression of the enzyme complex was repressed by several mono- and disaccharides including lactose, mannose, glucose, cellobiose, arabinose, raffinose, sucrose, xylose and fructose. Addition of pectin, starch and carboxymethyl cellulose to the colloidal chitin-containing medium, increased chitinase production. The enzyme tolerated a wide range of temperature (30-50 °C) and pH (5.5-8). Among various divalent cations Hg 2+ Cd 2+ and Ni 2+ completely inhibited the purified enzyme while Mg 2+ stimulated its activity. The crude or purified enzyme had potential for cell wall lysis of many phytopathogenic fungi tested.

Purification and characterization of an exochitinase from Bacillus thuringiensis subsp. aizawai and its action against phytopathogenic fungi

Abstract: A chitinolytic enzyme from Bacillus thuringiensis subsp. aizawai has been purified and its molecular mass was estimated ca. 66 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was able to hydrolyze chitin to chitobiosides but not carboxymethylcellulose, cellulose, pullulan, and laminarin. Optimal pH and temperature were detected at 6 and 50 degrees C, respectively. Stability, in the absence of substrate, was observed at temperatures less than 60 degrees C and pH between 5 and 8. Enzyme activity was significantly inhibited by K+ and EDTA and completely inhibited by Hg2+. Purified chitinase showed lytic activity against cell walls from six phytopathogenic fungi and inhibited the mycelial growth of both Fusarium sp. and Sclerotium rolfsii. The biocontrol efficacy of the enzyme was tested in the protection of bean seeds infested with six phytopathogenic fungi.

Functional characterization of three trehalase genes regulating the chitin metabolism pathway in rice brown planthopper using RNA interference.

Abstract: RNA interference (RNAi) is an effective gene-silencing tool and double stranded RNA (dsRNA) is considered a powerful strategy for gene function studies in insects. In the present study, we aimed to investigate the function of trehalase (TRE) genes (TRE 1-1, TRE 1-2 and TRE-2) isolated from the brown planthopper Nilaparvata lugens, a typical piercing-sucking insect in rice and investigate their regulating roles in chitin synthesis by injecting larvae with dsRNA. The results showed that TRE1 and TRE2 had compensatory function and the expression of each increased when the other was silenced. The total rate of insects with phenotypic deformities ranged from 19.83 to 24.36% after dsTRE injection, whereas the mortality rate ranged from 14.16 to 31.78%. The mRNA levels of genes involved in the chitin metabolism pathway in RNA-Seq and DGEP, namely hexokinase (HK), glucose-6-phosphate isomerase (G6PI) and chitinase (Cht), decreased significantly at 72 h after single dsTREs injection, whereas two transcripts of chitin synthase (CHS) genes decreased at 72 h after dsTRE1-1 and dsTREs injection. These results demonstrated that TRE silencing could affect the regulation of chitin biosynthesis and degradation, causing moulting deformities. Therefore, expression inhibitors of TREs might be effective tools for the control of planthoppers in rice.

Proteomic study of biocontrol mechanisms of Trichoderma harzianum ETS 323 in response to Rhizoctonia solani.

Abstract: To elucidate the entire range of proteins that are secreted by Trichoderma harzianum ETS 323 in its antagonism with Rhizoctonia solani, an in vivo interaction between them was mimicked and not only the secreted cell wall-degrading enzymes (CWDEs) but also all of the proteome were investigated. Seven CWDEs, chitinase, cellulase, xylanase, � -1,3-glucanase, � -1,6-glucanase, mannanase, and protease,were revealed by activity assay, in-gel activity stain, 2-DE, and LC-MS/MS analysis. Extracellular protein extracts from media that contained R. solani exhibited much higher CWDE activities than media that did not contain R. solani. Cellulase and mannanase activity, however, were insignificant. Activity stain also revealed that � -1,3-glucanase, � -1,6-glucanase, and xylanase activity occurred exclusively in media that contained R. solani. Furthermore, 35 of the 43 excised spots on the 2-DE gel were successfully analyzed by LC-MS/MS, and eight proteins were identified. They were two glycoside hydrolases, two proteases, two � -glucosidases, one endochitinase and, interestingly, one amino acid oxidase. Additionally, a possible mechanism was proposed to elucidate how the cell walls of R. solani are systematically enveloped and disintegrated.