Removal of Soil Microbes Alters Interspecific Competitiveness of Epichloë Endophyte-Infected over Endophyte-Free Leymus chinensis.

Hui Liu,Tianzi Qin,Anzhi Ren,Jing Chen,Xinjian Shi,Yubao Gao

doi:10.3390/microorganisms8020219

Abstract

Epichloë endophytes may not only affect the growth and resistances of host grasses, but may also affect soil environment including soil microbes. Can Epichloë endophyte-mediated modification of soil microbes affect the competitive ability of host grasses? In this study, we tested whether Epichloë endophytes and soil microbes alter intraspecific competition between Epichloë endophyte-colonized (EI) and endophyte-free (EF) Leymus chinensis and interspecific competition between L. chinensis and Stipa krylovii. The results demonstrated that Epichloë endophyte colonization significantly enhanced the intraspecific competitive ability of L. chinensis and that this beneficial effect was not affected by soil microbes. Under interspecific competition, however, significant interactions between Epichloë endophytes and soil microbes were observed. The effect of Epichloë endophytes on interspecific competitiveness of the host changed from positive to neutral with soil microbe removal. Here higher mycorrhizal colonization rates probably contributed to interspecific competitive advantages of EI over EF L. chinensis. Our result suggests that Epichloë endophytes can influence the competitive ability of the host through plant soil feedbacks from the currently competing plant species.

Highlights

Epichloë endophytes are a group of fungi characterized by their ability to infect the aerial tissues of several cool-season grasses without causing obvious disease [1]
We compared the competitiveness of EI relative to EF L. chinensis in intraspecific competition and mycorrhizal colonization rate among S, EIS and EFS in interspecific competition, so we only used one-way ANOVA examining the effect of M on the aggressivity index (AGR) of L. chinensis and determining the effect of C on the mycorrhizal colonization rate of S. krylovii
Growth of L. chinensis, in terms of Relative Yield (RY) was significantly increased by Epichloë endophyte colonization under both intra- and interspecific competition, but the extent of this effect was higher for intraspecific competition (26% versus 18%, respectively) (Table 2, Figure 2A,C)

Summary

Introduction

Epichloë endophytes are a group of fungi characterized by their ability to infect the aerial tissues of several cool-season grasses without causing obvious disease [1]. Epichloë endophytes may affect the growth and resistances of host grasses, but may affect soil microbes, such as nitrogen-fixing bacteria, phosphorus-solubilizing rhizospheric fungi, arbuscular mycorrhizal fungi (AMF) and other microbial communities [30,31,32,33]. Can Epichloë endophyte-mediated modification of soil microbes affect the competitive ability of host grasses indirectly? We investigated the effects of Epichloë endophytes and soil microbes on the intraspecific competitive interactions between EI and EF L. chinensis and interspecific competitive interactions between L. chinensis and S. krylovii. We focused on two primary questions: (1) Does Epichloë endophyte colonization affect the growth and intra- and interspecific competitive ability of L. chinensis? (2) Is the effect of Epichloë endophyte colonization on the growth and competitive ability of L. chinensis influenced by soil microbes? We focused on two primary questions: (1) Does Epichloë endophyte colonization affect the growth and intra- and interspecific competitive ability of L. chinensis? (2) Is the effect of Epichloë endophyte colonization on the growth and competitive ability of L. chinensis influenced by soil microbes?

Plant and Fungal Material

AMF Colonization Rate

Competitiveness

Statistical Analyses

Plant Growth Performance