Epichloë gansuensis Increases the Tolerance of Achnatherum inebrians to Low-P Stress by Modulating Amino Acids Metabolism and Phosphorus Utilization Efficiency

Abstract

In the long-term evolutionary process, Achnatherum inebrians and seed-borne endophytic fungi, Epichloë gansuensis, formed a mutually beneficial symbiosis relationship, and Epichloë gansuensis has an important biological role in improving the tolerance of host grasses to abiotic stress. In this work, we first assessed the effects of Epichloë gansuensis on dry weight, the content of C, N, P and metal ions, and metabolic pathway of amino acids, and phosphorus utilization efficiency (PUE) of Achnatherum inebrians at low P stress. Our results showed that the dry weights, the content of alanine, arginine, aspartic acid, glycine, glutamine, glutamic acid, L-asparagine, lysine, phenylalanine, proline, serine, threonine, and tryptophan were higher in leaves of Epichloë gansuensis-infected (E+) Achnatherum inebrians than Epichloë gansuensis-uninfected (E−) Achnatherum inebrians at low P stress. Further, Epichloë gansuensis increased C content of roots compared to the root of E− plant at 0.01 mM P and 0.5 mM P; Epichloë gansuensis increased K content of leaves compared to the leaf of E− plant at 0.01 mM P and 0.5 mM P. Epichloë gansuensis reduced Ca content of roots compared to the root of E− plant at 0.01 mM P and 0.5 mM P; Epichloë gansuensis reduced the content of Mg and Fe in leaves compared to the leaf of E− plant at 0.01 mM P and 0.5 mM P. In addition, at low P stress, Epichloë gansuensis most probably influenced aspartate and glutamate metabolism; valine, leucine, and isoleucine biosynthesis in leaves; and arginine and proline metabolism; alanine, aspartate, and glutamate metabolism in roots. Epichloë gansuensis also affected the content of organic acid and stress-related metabolites at low P stress. In conclusion, Epichloë gansuensis improves Achnatherum inebrians growth at low P stress by regulating the metabolic pathway of amino acids, amino acids content, organic acid content, and increasing PUE.

Interaction Between Grasses and <em>Epichloe</em> Endophytes and Its Significance to Biotic and Abiotic Stress Tolerance and the Rhi-Zosphere

“…These have also been shown to be produced in higher amounts in the shoots and roots of E+ grasses and can therefore also alter the microbial population [183]. Endophyte infection upregulates the production of other substances that have physiological implications such as amino acids and sugars [62,65]. We see this particularly under drought and salt stress where some of these substances have osmoregulatory properties.…”

“…A variety of studies have shown Epichloe infected grasses could be more tolerant to low nutrient inputs [59][60][61][62].…”

“…A study conducted on drunken horse grass and E. gansuensis found that the E+ grass was more tolerant to low P than the E-grass. This is likely due to the endophyte regulation of certain amino acids, amino acid metabolism and organic acids were found in E+ plants, which helps with nutrient metabolism and photosynthesis [62]. Additionally, an increase in vanillin, a ROS scavenging compound, which helps decrease oxidative damage was found in E+ grass [62].…”

“…This is likely due to the endophyte regulation of certain amino acids, amino acid metabolism and organic acids were found in E+ plants, which helps with nutrient metabolism and photosynthesis [62]. Additionally, an increase in vanillin, a ROS scavenging compound, which helps decrease oxidative damage was found in E+ grass [62]. Nutrient cycling in endophyte-infected plants is commonly tied to changes to the surrounding microbiome.…”

Correction: Liu et al. Epichloë gansuensis Increases the Tolerance of Achnatherum inebrians to Low-P Stress by Modulating Amino Acids Metabolism and Phosphorus Utilization Efficiency. J. Fungi 2021, 7, 390

“…In the original article [1], the wrong "Figure 2a,b" were uploaded due to author's negligence, there were mistakes in "Figure 2a,b" as published. The corrected "Figure 2a,b" appears below, and the corresponding detailed content have also been corrected.…”