Endophyte species influence the biomass production of the native grassAchnatherum sibiricum(L.) Keng under high nitrogen availability

Abstract

Research on the interaction of endophytes and native grasses normally takes infection status into account, but less often considers the species of endophyte involved in the interaction. Here, we examined the effect of endophyte infection, endophyte species, nitrogen availability, and plant maternal genotype on the performance of a wild grass, Achnatherum sibiricum. Six different Epichloë‐infected maternal lines of A. sibiricum were used in the study; three lines harbored Epichloë gansuensis (Eg), while three lines harbored Epichloë sibirica (Es). These endophytes are vertically transmitted, while Eg also occasionally produces stromata on host tillers. We experimentally removed the endophyte from some ramets of the six lines, with the infected (E+) and uninfected (E−) plants grown under varying levels of nitrogen availability. Eg hosts produced more aboveground biomass than Es hosts only under high nitrogen supply. Endophyte species did not show any influence on the maximum net photosynthetic rate (P max), photosynthetic nitrogen use efficiency, or total phenolics of A. sibiricum under all nitrogen conditions. However, the plant maternal genotype did influence the P max and shoot biomass of A. sibiricum. Our results show that endophyte species influenced the shoot biomass of A. sibiricum, and this effect was dependent on nitrogen supply. As with most coevolutionary interactions, A. sibiricum that harbored Eg and Es may show pronounced geographic variation in natural habitats with increased nitrogen deposition. In addition, stroma‐bearing endophyte (Eg) provides positive effects (e.g., higher biomass production) to A. sibiricum plants during the vegetative growth stage.

Endophytic Fungi Activated Similar Defense Strategies of Achnatherum sibiricum Host to Different Trophic Types of Pathogens

“…The phenomenon of double infections by both Epichloë species in the same plant has not been observed in A. sibiricum (Zhang et al, 2009;Li et al, 2015). Both E. sibirica and E. gansuensis improved the growth and competitive ability of A. sibiricum (Li et al, 2016;Zhou et al, 2019), and their main metabolites were also similar (our unpublished data). According to many years of observations in our laboratory, A. sibiricum exhibits no obvious herbivore deterrence, but its pathogen damage is usually less serious than in most neighboring plants of other species.…”

The Interaction between Arbuscular Mycorrhizal Fungi (AMF) and Grass Endophyte (Epichloë) on Host Plants: A Review

“…In AMF-grass endophyte-plants systems, Epichloë increases shoot/root phosphorus concentrations and net photosynthesis rates [ 44 , 52 , 55 , 61 , 62 ]. In this association, AMF provides a substantial amount of phosphorus-containing compounds to host plants in exchange for photosynthetic products [ 63 , 64 ].…”

Fungal endophytes can eliminate the plant growth–defence trade‐off

“…This nutrient limitation did reduce alkaloid concentrations, but final alkaloid levels were still within the range of biological activity (Ryan et al ., 2014a). Likewise, reduced soil nutrients did not affect endophyte‐mediated growth stimulation of A. sibiricum , a plant species that naturally grows in nutrient‐poor soils (Li et al ., 2016). It is possible that certain plant–endophyte associations have evolved tolerance to nutrient scarcity, which would allow endophytes to maintain the delivery of benefits to host plants.…”