Microbial Ecology

, 57:740

Imperfect Vertical Transmission of the Endophyte Neotyphodium in Exotic Grasses in Grasslands of the Flooding Pampa

  • Pedro E. Gundel
  • Lucas A. Garibaldi
  • Pedro M. Tognetti
  • Roxana Aragón
  • Claudio M. Ghersa
  • Marina Omacini
Original Article

DOI: 10.1007/s00248-008-9447-y

Cite this article as:
Gundel, P.E., Garibaldi, L.A., Tognetti, P.M. et al. Microb Ecol (2009) 57: 740. doi:10.1007/s00248-008-9447-y

Abstract

Cool-season grasses establish symbioses with vertically transmitted Neotyphodium endophytes widespread in nature. The frequency of endophyte-infected plants in closed populations (i.e., without migrations) depends on both the differential fitness between infected and non-infected plants, and the endophyte-transmission efficiency. Most studies have been focused on the first mechanism ignoring the second. Infection frequency and endophyte transmission from vegetative tissues to seeds were surveyed in two grasses growing in vegetation units that differ in flood and grazing regimes, and soil salinity. Transmission efficiency and infection frequency for tall fescue did not vary significantly and were 0.98 and 1.00, respectively. For Italian ryegrass, transmission efficiency and infection frequency were 0.88 and 0.57 in humid prairies, and 0.96 and 0.96 in the other vegetation units. Only in humid mesophytic meadows, the observed pattern was irrespective of the presence or absence of grazers. Our results suggest that selection forces for endophyte infection are different for both species. Imperfect transmission was only compensated in tall fescue through an increased fitness of infected plants. Interpreting variations of infection frequency only in terms of differential fitness can be misleading, considering that endophyte transmission can be imperfect and variable in nature. Therefore, this study highlights the importance of measuring transmission efficiency.

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Pedro E. Gundel
    • 1
  • Lucas A. Garibaldi
    • 2
    • 3
  • Pedro M. Tognetti
    • 2
  • Roxana Aragón
    • 2
  • Claudio M. Ghersa
    • 1
  • Marina Omacini
    • 1
  1. 1.IFEVA-CONICET, Cátedra de Ecología, Facultad de AgronomíaUniversidad de Buenos Aires (UBA)Buenos AiresArgentina
  2. 2.Cátedra de Métodos Cuantitativos Aplicados, Facultad de Agronomía (UBA)Buenos AiresArgentina
  3. 3.Laboratorio Ecotono-CONICET, Centro Regional Universitario BarilocheUniversidad Nacional del ComahueBarilocheArgentina