Plant endophytes and arbuscular mycorrhizal fungi alter plant competition.xlsx

<b>1. </b>In nature, grasses simultaneously establish multiple
symbiotic associations with endophytic fungi and arbuscular mycorrhizal fungi
(AMF). The effect of these multiple interactions on competitive interactions
between plants remains poorly understood.

<b>2. </b>In this study, we tested whether endophytes and AMF (<i>Glomus mosseae</i> or <i>Glomus etunicatum</i>) alter plant competition between a subordinate
plant species that associates with both symbionts (<i>Achnatherum sibiricum</i>) and a dominant plant species, <i>Stipa
grandis</i>, that only associates with one symbiont (AMF). And we hypothesized
that endophytes can facilitate the coexistence of the subordinate plant species
(<i>A</i>.<i> sibiricum</i>) and the dominant plant species (<i>S</i>.<i> grandis</i>).

<b>3. </b>The results demonstrated that endophyte infection
significantly enhanced the competitive ability of the subordinate plant species
compared to the dominant plant species. The effects of AMF on plant competition
were variable and depended on the identity of the AMF species. <i>G</i>.<i>
etunicatum</i> gave <i>A</i>.<i> sibiricum</i> plants a higher competitive
ability, while <i>G</i>.<i> mosseae</i> gave <i>S</i>.<i> grandis</i> a higher competitive ability. Simultaneous
infections of both endophytes and AMF in <i>A</i>.<i> sibiricum</i>
also altered the competitive relationships with <i>S</i>.<i> grandis</i>.

<b>4. </b>In conclusion, these results suggest that endophytic
fungi can facilitate the coexistence of a subordinate plant species with a
dominant plant species. Moreover, endophytes could not only affect the
competitive ability of the host plant directly but also indirectly by interacting
with different AMF to change the growth of competing plant species.