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- Bordallo, JJ, et al.
(författare)
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Colonization of plant roots by egg-parasitic and nematode-trapping fungi
- 2002
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Ingår i: New Phytologist. - : Wiley. - 1469-8137 .- 0028-646X. ; 154:2, s. 491-499
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Tidskriftsartikel (refereegranskat)abstract
- • The ability of the nematode-trapping fungus Arthrobotrys oligospora and the nematode egg parasite Verticillium chlamydosporium to colonize barley (Hordeum vulgare) and tomato (Lycopersicum esculentum) roots was examined, together with capability of the fungi to induce cell wall modifications in root cells. • Chemotropism was studied using an agar plate technique. Root colonization was investigated with light microscopy and scanning electron microscopy, while compounds involved in fungus–plant interactions were studied histochemically. • Only A. oligospora responded chemotropically to roots. Colonization of barley and tomato by both fungi involved appressoria to facilitate epidermis penetration. V. chlamydosporium colonized tomato root epidermis and produced chlamydospores. Papillae, appositions and lignitubers ensheathing hyphae on tomato were also found. Phenolics (including lignin), protein deposits and callose were present in papillae in both hosts. Both fungi were still present in epidermal cells 3 months after inoculation. • Nematophagous fungi colonized endophytically monocotyledon and dicotyledon plant roots. Arthrobotrys oligospora seemed to be more aggressive than V. chlamydosporium on barley roots. Both fungi induced cell wall modifications, but these did not prevent growth. The response of root cells to colonization by nematophagous fungi may have profound implications in the performance of these organisms as biocontrol agents of plant parasitic nematodes.
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| 2. |
- Tikhonov, VE, et al.
(författare)
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Purification and characterization of chitinases from the nematophagous fungi Verticillium chlamydosporium and v. suchlasporium
- 2002
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845. ; 35:1, s. 67-78
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Tidskriftsartikel (refereegranskat)abstract
- Culture filtrates of the nematophagous fungi Verticillium chlamydosporium and V. suchlasporium growing on colloidal chitin showed increasing chitinolytic activity and production of two (32- and 43-kDa) main proteins. Maximum activity was found 18-20 days after inoculation, but V. suchlasporium always displayed higher activity. Zymography of such filtrates on carboxymethyl-chitin-Remazol brilliant violet 5R/acrylamide gels showed five bands of substrate degradation for V. suchlasporium and three for V. chlamydosporium. Filtrates with maximum activity were chromatographed on macroporous cross-linked chitin affinity matrix, showing a peak of main (50-60%) activity, which only contained a 43-kDa protein for both fungi. Zymography and colloidal chitin degradation showed that it was a single endochitinase (CHl43) with optimum pH range of 5.2-5.7. The main isoforms had pis of 7.6 for V. suchlasporium and 7.9 for V. chlamydosporium. Eggs of the nematode Globodera pallida treated with CHl43 and the serine protease P32 from V. suchlasporium alone or in combination showed surface damage in comparison with controls when examined by scanning electron microscopy. (C) 2002 Elsevier Science (USA).
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