High nitrogen supply and carbohydrate content reduce fungal endophyte and alkaloid concentration in Lolium perenne
Article first published online: 12 DEC 2006
Volume 173, Issue 4, pages 787–797, March 2007
How to Cite
Rasmussen, S., Parsons, A. J., Bassett, S., Christensen, M. J., Hume, D. E., Johnson, L. J., Johnson, R. D., Simpson, W. R., Stacke, C., Voisey, C. R., Xue, H. and Newman, J. A. (2007), High nitrogen supply and carbohydrate content reduce fungal endophyte and alkaloid concentration in Lolium perenne. New Phytologist, 173: 787–797. doi: 10.1111/j.1469-8137.2006.01960.x
- Issue published online: 12 DEC 2006
- Article first published online: 12 DEC 2006
- Received: 11 September 2006 Accepted: 2 November 2006
- endophytic fungi;
- high sugar grass;
- lolitrem B;
- Lolium perenne;
- Neotyphodium lolii;
- quantitative PCR (qPCR)
- • The relationship between cool-season grasses and fungal endophytes is widely regarded as mutualistic, but there is growing uncertainty about whether changes in resource supply and environment benefit both organisms to a similar extent.
- • Here, we infected two perennial ryegrass (Lolium perenne) cultivars (AberDove, Fennema) that differ in carbohydrate content with three strains of Neotyphodium lolii (AR1, AR37, common strain) that differ intrinsically in alkaloid profile. We grew endophyte-free and infected plants under high and low nitrogen (N) supply and used quantitative PCR (qPCR) to estimate endophyte concentrations in harvested leaf tissues.
- • Endophyte concentration was reduced by 40% under high N supply, and by 50% in the higher sugar cultivar. These two effects were additive (together resulting in 75% reduction). Alkaloid production was also reduced under both increased N supply and high sugar cultivar, and for three of the four alkaloids quantified, concentrations were linearly related to endophyte concentration.
- • The results stress the need for wider quantification of fungal endophytes in the grassland–foliar endophyte context, and have implications for how introducing new cultivars, novel endophytes or increasing N inputs affect the role of endophytes in grassland ecosystems.