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High nitrogen supply and carbohydrate content reduce fungal endophyte and alkaloid concentration in Lolium perenne
Author(s) -
Rasmussen Susanne,
Parsons Anthony J.,
Bassett Shalome,
Christensen Michael J.,
Hume David E.,
Johnson Linda J.,
Johnson Richard D.,
Simpson Wayne R.,
Stacke Christina,
Voisey Christine R.,
Xue Hong,
Newman Jonathan A.
Publication year - 2007
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2006.01960.x
Subject(s) - endophyte , lolium perenne , neotyphodium , biology , perennial plant , cultivar , epichloë , agronomy , poaceae , botany , sugar , grassland , lolium , symbiosis , food science , bacteria , genetics
Summary• 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.