Environmental Entomology (2011) 40, 639-647

Michael W. Baldauf, Wade J. Mace and Douglas S. Richmond (2011)
Endophyte-mediated resistance to black cutworm as a function of plant cultivar and endophyte strain in tall fescue
Environmental Entomology 40 (3), 639-647
Abstract: To improve Neotyphodium endophyte-mediated resistance to black cutworm Agrotis ipsilon (Hufnagel) (BCW), a series of experiments was conducted by using several different cultivars of tall fescue, Schedonorus arundinaceus (Schreb.) Dumort. in combination with several different haplotypes of the endophyte Neotyphodium coenophialum (Morgan-Jones and Gams) (plant cultivar × endophyte haplotype = plant line), each producing unique alkaloid profiles. BCW settling response, survival at 5 and 10 d, and larval biomass varied significantly among plant lines. In general, greater variation BCW performance was observed within a single plant cultivar infected with different endophyte haplotypes than among different plant cultivars infected with the same endophyte haplotype, but comparisons among the former were far more numerous. Although five endophytemediated alkaloids representing three alkaloid classes were quantified in the plants, the pyrrolizidine alkaloid N-acetyl norloline was consistently the single best predictor of BCW performance. BCW settling response, 5-d survival, and 10-d survival decreased as levels of the alkaloid N-acetyl norloline increased. The same three response variables also decreased with increasing levels of peramine, but increased with increasing levels of ergovaline. Minor variation in endophyte infection levels occurring among infected plant lines had no significant influence on BCW performance. Results indicate a potentially important role for N-acetyl norloline and peramine in providing resistance to black cutworm whereas ergovaline appears to be much less important. Therefore, endophyte haplotypes expressing high levels of N-acetyl norloline and peramine may be of particular importance for developing 'friendly' endophyte-enhanced turf and pasture grasses that resist challenging lepidopteran pests, although remaining safe for wildlife and grazing mammals.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Douglas S. Richmond

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
molecular biology - genes
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Agrotis ipsilon	Festuca (crop)
Epichloë coenophiala (entomopathogen)	Agrotis ipsilon	Festuca (crop)