Does Epichloë Endophyte Enhance Host Tolerance to Root Hemiparasite?

Area of Science:

• Plant-microbe interactions
• Ecology
• Biocontrol

Background:

• Epichloë endophytes are mutualistic symbionts of cool-season grasses.
• The impact of endophytic symbiosis on plant-parasite interactions is understudied.
• Parasitic plants can significantly affect host performance.

Purpose of the Study:

• To investigate the effect of Epichloë endophyte symbiosis on host grass performance under hemiparasite attack.
• To examine context-dependent interactions between endophytes, host grasses, and a hemiparasite.
• To explore the potential of grass-endophyte symbionts as biocontrol agents.

Main Methods:

• Greenhouse experiment with two host grasses (Stipa purpurea, Elymus tangutorum) and a hemiparasite (Pedicularis kansuensis).
• Comparison of endophyte-infected and endophyte-free host plants, with and without the hemiparasite.
• Measurements included plant biomass, tillers, root:shoot ratio, photosynthetic parameters, and hemiparasite haustoria.

Main Results:

• Pedicularis kansuensis reduced host performance but increased its own biomass and survival.
• Endophyte-infected S. purpurea showed improved growth and reduced hemiparasite impact compared to endophyte-free plants.
• Endophyte-infected E. tangutorum exhibited reduced performance and increased hemiparasite parasitism compared to endophyte-free plants.
• Endophytes from S. purpurea alleviated host biomass reduction and hemiparasite growth.

Conclusions:

• Endophyte-host grass interactions are context-dependent and influenced by plant-plant interactions.
• Epichloë endophytes can mediate host resistance to hemiparasites.
• Grass-endophyte symbionts show promise for biocontrol of weedy hemiparasites.