Are Epichloë endophytes specific to Elymus grass hosts?

Area of Science:

• Mycology
• Plant-microbe interactions
• Grass genetics

Background:

• Epichloë endophytes are symbiotic fungi mutualistic with cool-season grasses, offering protection against various stresses.
• Previous research indicated host specificity of Epichloë endophytes in Festuca and Lolium, but this was unexamined in Chinese Elymus species.

Purpose of the Study:

• To investigate the host specificity of asexual Epichloë endophytes in Chinese Elymus species.
• To analyze phylogenetic relationships between Chinese Elymus, their diploid donors (Hordeum), and associated Epichloë endophytes.

Main Methods:

• Phylogenetic analysis of Epichloë endophyte sequences from Chinese Elymus and Hordeum species.
• Comparison of endophyte sequences with those from North American Elymus species.

Main Results:

• Chinese Elymus species received their maternal donors from Chinese Pseudoroegneria (St genome) or Hordeum (H genome).
• Chinese Hordeum species harbored two Epichloë endophyte species; one was also found in North American Elymus, the other in Chinese Elymus.
• Epichloë endophytes isolated from Elymus species exhibited no strict grass-host specificity.
• Plant hybridization is hypothesized to be a mechanism for transforming endophyte-free (E-) to endophyte-infected (E+) plants.

Conclusions:

• The study challenges previous notions of Epichloë endophyte specificity, particularly within the Elymus genus.
• Plant hybridization is proposed as a significant factor in the transmission and distribution of Epichloë endophytes among grasses.
• Findings contribute to understanding the evolutionary dynamics of grass-endophyte associations.