Influence of Epichloë bromicola endophytic fungi on secondary metabolites following alkali tolerance improvement in host, Hordeum bogdanii
Abstract Purpose: The aim of this study was to investigate how endophytic fungi affect secondary metabolites of H. bogdanii under alkaline stress at different concentrations. It is currently unclear whether the mechanism via which endophytic fungi improve the alkali tolerance of Hordeum bogdanii affects secondary metabolites. Unveiling this knowledge is crucial for understanding the tolerance mechanism of H. bogdanii to alkaline stress. Methods: Endophyte-infected (E+) and endophyte-free (E-) individuals of H. bogdanii were used as materials in this study. Vermiculite was used for plant cultivation and was carried out in the laboratory. After mixed alkali stress treatment, the roots, stems, and leaves of the plants were collected to measure the indicators related to secondary metabolites. Results: The results showed that endophytic fungi significantly increased the contents of phosphorus, polyphenols, and alkaloids, and the activities of polyphenol oxidase and acid phosphatase, and significantly reduced flavonoid content. The content of polyphenols and alkaloids in stems, polyphenol oxidase activity in stems and leaves, and acid phosphatase activity in leaves were significantly affected. In general, endophytic fungi improved the alkali resistance of H. bogdanii by improving the related indicators of secondary metabolites. Conclusions: The findings of this study may aid in amplifying the alkali resistance mechanism of endophytic fungi to H. bogdanii as well as provide insights into improving the alkali resistance of other plants.