A fungus among us: Broad patterns of endophyte distribution in the grasses

Jennifer A. Rudgers, Michelle E. Afkhami, Megan A. Rúa, Andrew J. Davitt, Samantha Hammer, Valérie M. Huguet

Research output: Contribution to journalArticlepeer-review

84 Scopus citations


Plant-associated microbes have been increasingly recognized for influencing host populations, plant communities, and even herbivores and predators. Thus, understanding factors that affect the distribution and abundance of microbial symbioses may be important for predicting the ecological dynamics of communities. Using endophytic fungi-grass symbioses, we explored how intrinsic traits of the symbiosis, specifically transmission mode, may influence symbiont frequencies in host populations. Combining published literature with new field surveys, we compared Epichloë endophytes, which had mixed horizontal and vertical transmission, with Neotyphodium endophytes, which were exclusively vertically transmitted from host plants to seeds. Exclusively vertical transmission should select against pathogenicity because symbionts depend entirely on hosts for reproduction. Across 118 host species, we found that Neotyphodium hosts had 40-130% higher symbiont frequencies than Epichloë hosts. In field surveys, endophyte frequency was positively correlated with the local density of hosts, but only for Epichloë, suggesting that contagiously spread Epichloë may attain higher frequencies when hosts are more abundant. Epichloë endophytes were also more likely than Neotyphodium to have imperfect vertical transmission; thus, hosts may reduce the transmission of more pathogenic symbionts to seeds. Results are consistent with the conclusion that the evolutionary transition to exclusively vertical transmission can alter patterns of symbiont frequency in nature.

Original languageEnglish (US)
Pages (from-to)1531-1539
Number of pages9
Issue number6
StatePublished - Jun 2009
Externally publishedYes


  • Endophytic fungi-grass symbioses
  • Epichloe spp.
  • Neotyphodium spp.
  • Plant-microbe
  • Poaceae
  • Symbiosis
  • Vertical transmission

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


Dive into the research topics of 'A fungus among us: Broad patterns of endophyte distribution in the grasses'. Together they form a unique fingerprint.

Cite this