The insecticidal loline alkaloids, produced by Neotyphodium uncinatum and related endophytes, are exo-1-aminopyrrolizidines with an ether bridge between C-2 and C-7. Loline alkaloids vary in methyl, acetyl, and formyl substituents on the 1-amine, which affect their biological activity. Enzymes for key loline biosynthesis steps are probably encoded by genes in the LOL cluster, which is duplicated in N. uncinatum, except for a large deletion in lolP2. The role of lolP1 was investigated by its replacement with a hygromycin B phosphotransferase gene. Compared to wild type N. uncinatum and an ectopic transformant, ΔlolP1 cultures had greatly elevated levels of N-methylloline (NML) and lacked N-formylloline (NFL). Complementation of ΔlolP1 with lolP1 under control of the Emericella nidulans trpC promoter restored NFL production. These results and the inferred sequence of LolP1 indicate that it is a cytochrome P450, catalyzing oxygenation of an N-methyl group in NML to the N-formyl group in NFL.
|Number of pages||8|
|Journal||Fungal Genetics and Biology|
|State||Published - Sep 2008|
Bibliographical noteFunding Information:
This work was supported by US National Science Foundation Grant MCB-0213217 and U.S. Department of Agriculture Grant 200506271031. We thank Walter Hollin, Alfred D. Byrd, and LaTasha S. Williams for valuable technical support. Sequence analyses were conducted in the University of Kentucky Advanced Genetic Technologies Center. This is Kentucky Agricultural Experiment Station publication number 08-12-090, published with the approval of the director.
- Grass endophyte
- Loline alkaloids
- Neotyphodium uncinatum
- P450 monooxygenase
ASJC Scopus subject areas