Purification and properties of a Meloidogyne-antagonistic chitinase from Lysobacter capsici YS1215

Abstract

The root-knot nematodes, Meloidogyne spp., cause serious diseases in various plants and their chemical control may lead to environmental problems. Therefore, alternative control measures against the phytopathogenic nematodes are being sought. One of the potential targets against Meloidogyne spp. may be the chitinolysis and degradation of nematode eggs. Therefore, in the present study, a chitinolytic and nematicidal strain of Lysobacter capsici YS1215 was isolated from an agricultural field in Korea. The aim of this study was to purify chitinase secreted by L. capsici YS1215 and investigate its nematicidal role against Meloidogyne incognita. The chitinase secreted by L. capsici YS1215 was purified by protein precipitation with 80% ammonium sulphate, anion-exchange chromatography with DEAE-cellulose and gel-filtration chromatography with Sephadex G-100. By chitinase-active staining of the purified enzyme, a single band was obtained with an estimated molecular mass of 43.6 kDa. The optimal pH and optimal temperature for the highest chitinase activity were 6.0 and 40°C, respectively. The purified chitinase degraded the chitin layer of the eggshells and significantly reduced hatch of second-stage juveniles. The activity of chitinase secreted by L. cap.úci YS1215 was not affected by CoCh, MnCl2, MgCl2, CUSO4, CaCl2 or EDTA. The purified enzyme could also hydrolyse swollen chitin, glycol chitin, glycol chitosan and chitin powder Thus, the role of chitinase secreted by L. capsici YS1215 against Meloidogyne spp. may be useful for further development of a biocontrol agent.

Statistical optimization of medium components for chitinase production byPseudomonas fluorescensstrain HN1205: role of chitinase on egg hatching inhibition of root-knot nematode

“…The destruction of eggshell structures by the chitinase was clearly demonstrated under the light microscope ( Figure 3). [45] As a result of this experiment, the chitinase inhibited egg hatching and degraded nematodes eggshells, which are composed of chitin. This may be the reason why the chitinase reduced the egg hatching.…”

“…[46] The purified chitinase LPCHI1 degraded the chitinous layer of M. incognita eggs and significantly influenced their development. [47,45] Meloidogyne javanica eggs were swollen when treated with chitinase and the structure of the eggshells was destroyed. [45,48] Purified chitinases produced from the nematophagous fungi Verticillium chlamydosporium and Verticillium suchlasporium showed cuticle damage on the eggs of Globodera pallida, which is a plant pathogenic nematode.…”

“…[47,45] Meloidogyne javanica eggs were swollen when treated with chitinase and the structure of the eggshells was destroyed. [45,48] Purified chitinases produced from the nematophagous fungi Verticillium chlamydosporium and Verticillium suchlasporium showed cuticle damage on the eggs of Globodera pallida, which is a plant pathogenic nematode. [49] The chitinase activity of Lysobacter capsici YS1215 was induced when M. incognita eggs were added as a chitin supplement during the incubation.…”

Optimal Medium Composition Suitable for Enhancement of Biofertilizer's Shelf Life

“…Therefore, low-cost materials of good quality are needed in order to produce biofertilizers with an excellent shelf life even under adverse storage conditions. Chitinous materials from marine waste have been used as a source of material for the growth of microorganisms that produce chitinolytic and proteolytic enzymes (Liu et al, 2003;Lee et al, 2014). Gelatin is derived from collagen obtained from various animal by-products, and is a good source of growth-promoting substances for bacteria (Stewart et al, 1938).…”

“…Lysobacter capsici YS1215 was previously isolated in Korea. It produced the chitinolytic and gelatinolytic enzymes, and showed antifungal and nematicidal activities (Lee et al, 2013a;Lee et al, 2013b;Lee et al, 2014). Hence, the objective of this study is to investigate the best optimal medium composition for the shelf life of the biofertilizer (L. capsici YS1215) using media supplemented with crab shell and gelatin powder, or with commercial TSB media.…”