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Indole-diterpene biosynthetic capability of epichloƫ endophytes as predicted by ltm gene analysis.
- Source :
-
Applied and environmental microbiology [Appl Environ Microbiol] 2009 Apr; Vol. 75 (7), pp. 2200-11. Date of Electronic Publication: 2009 Jan 30. - Publication Year :
- 2009
-
Abstract
- Bioprotective alkaloids produced by Epichloë and closely related asexual Neotyphodium fungal endophytes protect their grass hosts from insect and mammalian herbivory. One class of these compounds, known for antimammalian toxicity, is the indole-diterpenes. The LTM locus of Neotyphodium lolii (Lp19) and Epichloë festuce (Fl1), required for the biosynthesis of the indole-diterpene lolitrem, consists of 10 ltm genes. We have used PCR and Southern analysis to screen a broad taxonomic range of 44 endophyte isolates to determine why indole-diterpenes are present in so few endophyte-grass associations in comparison to that of the other bioprotective alkaloids, which are more widespread among the endophtyes. All 10 ltm genes were present in only three epichloë endophytes. A predominance of the asexual Neotyphodium spp. examined contained 8 of the 10 ltm genes, with only one N. lolii containing the entire LTM locus and the ability to produce lolitrems. Liquid chromatography-tandem mass spectrometry profiles of indole-diterpenes from a subset of endophyte-infected perennial ryegrass showed that endophytes that contained functional genes present in ltm clusters 1 and 2 were capable of producing simple indole-diterpenes such as paspaline, 13-desoxypaxilline, and terpendoles, compounds predicted to be precursors of lolitrem B. Analysis of toxin biosynthesis genes by PCR now enables a diagnostic method to screen endophytes for both beneficial and detrimental alkaloids and can be used as a resource for screening isolates required for forage improvement.
- Subjects :
- Blotting, Southern
Chromatography, Liquid
DNA, Fungal genetics
Diterpenes pharmacology
Indoles pharmacology
Lolium chemistry
Mass Spectrometry
Multigene Family
Mycotoxins metabolism
Mycotoxins pharmacology
Neotyphodium genetics
Neotyphodium metabolism
Neurotoxins metabolism
Neurotoxins pharmacology
Polymerase Chain Reaction methods
Diterpenes metabolism
Epichloe genetics
Epichloe metabolism
Fungal Proteins genetics
Indoles metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1098-5336
- Volume :
- 75
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Applied and environmental microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 19181837
- Full Text :
- https://doi.org/10.1128/AEM.00953-08