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Pre-penetration events in fungal parasitism of nematode eggs

Lopez-Llorcz, LV; Olivares-Bernabeu, C; Salinas, J; Jansson, Hans-Börje LU and Kolattukudy, PE (2002) In Mycological Research1989-01-01+01:002010-01-01+01:00 106. p.499-506
Abstract
The present investigation deals with the main factors involved in early infection of nematode eggs by fungal parasites. We studied the effect of hydrophobicity on appressorium formation by germlings of Pochonia rubescens (syn. Verticillium suchlasporium), P. chlamydosporia (syn. V. chlamydosporium) and Lecanicillium lecanii (syn. V. lecanii). Appressoria were frequently formed on hydrophobic surfaces such as polyvinyl chloride or polystyrene and were infrequently formed on hydrophilic materials such as glass or aluminium. Infected eggs probed with the FITC-labelled lectin Concanavalin-A showed intense labelling corresponding to appressoria formed by fungal parasites on the eggshell surface. Proteolytic activity was found in extracts from... (More)
The present investigation deals with the main factors involved in early infection of nematode eggs by fungal parasites. We studied the effect of hydrophobicity on appressorium formation by germlings of Pochonia rubescens (syn. Verticillium suchlasporium), P. chlamydosporia (syn. V. chlamydosporium) and Lecanicillium lecanii (syn. V. lecanii). Appressoria were frequently formed on hydrophobic surfaces such as polyvinyl chloride or polystyrene and were infrequently formed on hydrophilic materials such as glass or aluminium. Infected eggs probed with the FITC-labelled lectin Concanavalin-A showed intense labelling corresponding to appressoria formed by fungal parasites on the eggshell surface. Proteolytic activity was found in extracts from conidia and germlings of fungal parasites (especially P. chlamydosporia) in the absence of nematode eggs. Addition of the serine proteinase inhibitors phenylmetylsulphonyl fluoride (PMSF) or diisopropyl fluorophosphonate (DFP) to the extracts reduced their proteolytic activity. PMSF was the most effective inhibitor. Zymography also revealed proteolytic activity in extracts from the three fungi tested. This activity mostly corresponded to bands of Rf's of substrate degradation similar to that Of purified main protease (P32) from P. rubescens. Other bands with molecular weight higher than P32 (low Rf) were found especially for P. chlamydosporia extracts. For L. lecanii only bands of low Rf were found. Serum anti-P32 partially inhibited proteolytic activity of extracts from conidia and germlings. Application of PMSF and DFP to the inoculum, reduced egg penetration for the three species studied. PMSF caused the highest reduction in eggs infected by L. lecanii, while DFP significantly reduced egg infection by both P. chlamydosporia and L. lecanii. Our results therefore show hydrophobicity, appresorium formation and protease production as factors involved in early parasitism of nematode eggs. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Mycological Research1989-01-01+01:002010-01-01+01:00
volume
106
pages
499 - 506
publisher
Elsevier
external identifiers
  • wos:000177389000016
  • scopus:0036066646
ISSN
1469-8102
DOI
10.1017/S0953756202005798
language
English
LU publication?
yes
id
829ddae9-1c13-4ad3-8071-1a9552f7cf2b (old id 331629)
date added to LUP
2007-11-16 12:53:15
date last changed
2017-11-28 14:56:32
@article{829ddae9-1c13-4ad3-8071-1a9552f7cf2b,
  abstract     = {The present investigation deals with the main factors involved in early infection of nematode eggs by fungal parasites. We studied the effect of hydrophobicity on appressorium formation by germlings of Pochonia rubescens (syn. Verticillium suchlasporium), P. chlamydosporia (syn. V. chlamydosporium) and Lecanicillium lecanii (syn. V. lecanii). Appressoria were frequently formed on hydrophobic surfaces such as polyvinyl chloride or polystyrene and were infrequently formed on hydrophilic materials such as glass or aluminium. Infected eggs probed with the FITC-labelled lectin Concanavalin-A showed intense labelling corresponding to appressoria formed by fungal parasites on the eggshell surface. Proteolytic activity was found in extracts from conidia and germlings of fungal parasites (especially P. chlamydosporia) in the absence of nematode eggs. Addition of the serine proteinase inhibitors phenylmetylsulphonyl fluoride (PMSF) or diisopropyl fluorophosphonate (DFP) to the extracts reduced their proteolytic activity. PMSF was the most effective inhibitor. Zymography also revealed proteolytic activity in extracts from the three fungi tested. This activity mostly corresponded to bands of Rf's of substrate degradation similar to that Of purified main protease (P32) from P. rubescens. Other bands with molecular weight higher than P32 (low Rf) were found especially for P. chlamydosporia extracts. For L. lecanii only bands of low Rf were found. Serum anti-P32 partially inhibited proteolytic activity of extracts from conidia and germlings. Application of PMSF and DFP to the inoculum, reduced egg penetration for the three species studied. PMSF caused the highest reduction in eggs infected by L. lecanii, while DFP significantly reduced egg infection by both P. chlamydosporia and L. lecanii. Our results therefore show hydrophobicity, appresorium formation and protease production as factors involved in early parasitism of nematode eggs.},
  author       = {Lopez-Llorcz, LV and Olivares-Bernabeu, C and Salinas, J and Jansson, Hans-Börje and Kolattukudy, PE},
  issn         = {1469-8102},
  language     = {eng},
  pages        = {499--506},
  publisher    = {Elsevier},
  series       = {Mycological Research1989-01-01+01:002010-01-01+01:00},
  title        = {Pre-penetration events in fungal parasitism of nematode eggs},
  url          = {http://dx.doi.org/10.1017/S0953756202005798},
  volume       = {106},
  year         = {2002},
}