Relationship between production of the phytotoxin prehelminthosporol and virulence in isolates of the plant pathogenic fungus Bipolaris sorokiniana

Research output: Contribution to journalArticle

Abstract

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5 ng mul(-)1 (signal to noise ratio 4 : 1) which corresponds to ca. 15 ng prehelminthosporol per mg dry weight of mycelium or 15 ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.

Details

Authors
  • D Apoga
  • H Akesson
  • Hans-Börje Jansson
  • G Odham
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Ecology

Keywords

  • Helminthosporium sativum, Cochliobolus sativus, Bipolaris zeicola, Bipolaris setariae, Bipolaris victoriae, virulence, toxin, Hordeum vulgare
Original languageEnglish
Pages (from-to)519-526
JournalEuropean Journal of Plant Pathology
Volume108
Issue number6
Publication statusPublished - 2002
Publication categoryResearch
Peer-reviewedYes