Epichloë endophyte modifies the foliar anatomy of Lolium multiflorum Lam.

Abstract

Systemic fungal endophytes may increase the adaptive potential of their hosts to different environmental conditions. However, the mechanisms involved in the adjustment are still an area of active inquiry. Considering that anatomical features in plants are the result of adaptation to different environments, this aspect of plants response to the symbionts deserves further research. In this work we investigated whether an asexual Epichloe endophyte modifies the foliar anatomy of symbiotic plants (E+) of its host grass with respect to endophyte-free plants (E-), using the Epichloe occultans–Lolium multiflorum system. The experiment was carried out in a greenhouse and plants were grown under benign, non-stressful (controlled) conditions. Symbiotic plants showed thinner leaf blades and lower mesophyll thickness. Likewise, the endophyte is associated with a greater number of vascular bundles. The stomatal density on the lower epidermis was higher in symbiotic plants than non-symbiotic plants. Our study reveals that Epichloe occultans modifies the foliar anatomy of Lolium multiflorum. Considering that leaf anatomy exhibits characters that were selected as a result of evolution in relation to specific environmental conditions, these results are promising since they can offer information about the mechanisms involved in the adaptive adjustment of symbiotic plants.