IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Epichloë endophytes alter inducible indirect defences in host grasses.
Autor/es:
LI, T.; BLANDE, J.D.; GUNDEL, P.E.; HELANDER M. & K. SAIKKONEN.
Revista:
PLOS ONE
Editorial:
PUBLIC LIBRARY SCIENCE
Referencias:
Lugar: San Francisco; Año: 2014 vol. 9 p. 1 - 11
ISSN:
1932-6203
Resumen:
Epichloë endophytes are common symbionts living asymptomatically in pooid grasses and may provide chemical defences against herbivorous insects. While the mechanisms underlying these fungal defences have been well studied, it remains unknown whether endophyte presence affects the host?s own defences. We addressed this issue by examining variation in the impact ofEpichloe¨on constitutive and herbivore-induced emissions of volatile organic compounds (VOC), a well-known indirect plant defence, between two grass species, Schedonorus phoenix(ex. Festuca arundinacea; tall fescue) and Festuca pratensis(meadow fescue). We found that feeding by a generalist aphid species, Rhopalosiphum padi, induced VOC emissions by uninfected plants of both grass species but to varying extents, while mechanical wounding failed to do so in both species after one day of damage. Interestingly, regardless of damage treatment,Epichloe¨uncinata-infectedF. pratensis emitted significantly lower quantities of VOCs than their uninfected counterparts. In contrast,Epichloe¨coenophiala-infected S. phoenixdid not differ from their uninfected counterparts in constitutive VOC emissions but tended to increase VOC emissions under intense aphid feeding. A multivariate analysis showed that endophyte status imposed stronger differences in VOC profiles of F. pratensis than damage treatment, while the reverse was true for S. phoenix. Additionally, both endophytes inhibited R. padipopulation growth as measured by aphid dry biomass, with the inhibition appearing greater in E. uncinata-infected F. pratensis. Our results suggest, not only that Epichloe¨ endophytes may play important roles in mediating host VOC responses to herbivory, but also that the magnitude and direction of such responses may vary with the identity of the Epichloë?grass symbiosis. WhetherEpichloe¨-mediated host VOC responses will eventually translate into effects on higher trophic levels merits future investigation.