Expressed sequence tags and genes associated with loline alkaloid expression by the fungal endophyte Neotyphodium uncinatum

Martin J. Spiering, Heather H. Wilkinson, Jimmy D. Blankenship, Christopher L. Schardl

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

Loline alkaloids (LA), which are 1-aminopyrrolizidines with an oxygen bridge, are produced by Epichloë (anamorph = Neotyphodium) species, endophytes of grasses. LA are insecticidal, thus, helping to protect host plants from insect herbivory. The objective of this study was to identify genes associated with LA biosynthesis. Suppression subtractive hybridization PCR was used to isolate transcripts up-regulated during LA production in cultures of Neotyphodium uncinatum. Subtracted cDNAs were cloned and a λ-phage cDNA library from an LA-expressing N. uncinatum culture was screened with subtracted cDNA. In BLAST searches, several cDNAs identified had sequence similarities to aspartate kinases and another with O-acetylhomoserine-(thiol)lyase. Differential expression of these two genes in LA-producing cultures of N. uncinatum was confirmed and in a survey of 23 isolates from 21 Neotyphodium and Epichloë species these two genes strictly correlated with LA production. These findings open up the possibility for detailed studies on genes and enzymes involved in LA production.

Original languageEnglish
Pages (from-to)242-254
Number of pages13
JournalFungal Genetics and Biology
Volume36
Issue number3
DOIs
StatePublished - 2002

Bibliographical note

Funding Information:
This work was supported by the US National Science Foundation Integrative Plant Biology Program 9808554 to C.L.S. and US Department of Agriculture NRICGP grant 9901343 to H.H.W. We thank Ms Rebecca R. Singleton for assistance with the library screening and cDNA sequencing. We also thank Dr. Christina D. Moon and Mr. Kelly D. Craven for providing endophyte genomic DNAs and Mr. Alfred D. Byrd and Mr. Walter Hollin for technical assistance. This is contribution 02-12-49 of the Kentucky Agricultural Experiment Station, published with the approval of the Director.

Keywords

  • 1-aminopyrrolizidines
  • Aspartate kinase
  • Homocysteine synthase
  • Loline alkaloids
  • Neotyphodium uncinatum
  • Suppression subtractive hybridization

ASJC Scopus subject areas

  • Microbiology
  • Genetics

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