Metabolomics insights into the mechanism by which Epichloë gansuensis endophyte increased Achnatherum inebrians tolerance to low nitrogen stress

Abstract

Background and aim Epichloë gansuensis increases the tolerance of host plants to abiotic stress. However, little is known about the mechanism by which E. gansuensis improves grass growth under low nitrogen availability stress. Methods Achnatherum inebrians with E. gansuensis (E+) and without E. gansuensis (E-) were treated with modified 1/2 Hoagland containing 0.01 mM (low N) or 7.5 mM N (normal level) for 18 weeks. After 18 weeks of treatment with N, the dry weight of E+ and Eplants were measured, and the metabolomics analysis of leaves and roots grown under two different N concentrations was conducted with GSMS to determine differential metabolites and metabolic pathways. Result E+ A. inebrians had higher dry weight of leaves and roots compared to the EA. inebrians under low N stress. E. gansuensis increased the tolerance of A. inebrians to low N stress by its capability to increase the content of organic acids (salicylic acid and 3-hydroxypropionic acid) and glucose-6phosphate in leaves, and E. gansuensis increased the content of fatty acids (linolenic acid and oleic acid) and amino acids (glycine and 4-aminobutyric acid) in roots under low N stress. Finally, E. gansuensis reprogramed the metabolic pathway of amino acids of host grasses to adapt to the different N concentration. Conclusion Our results reveal the chemical mechanism by which E. gansuensis enhances the tolerance of host grasses to low N, and provide the theoretical basis for utilizing E. gansuensis, improving of grasses and crops, and for developing new germplasm for low-N tolerant grasses. Plant Soil https://doi.org/10.1007/s11104-021-04930-z Responsible Editor: Stéphane Compant W. Hou : J. Wang (*) : J. Liu :Y. Liu : C. Cheng State Key Laboratory of Grassland Agro-ecosystems, Center for Grassland Microbiome, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China e-mail: [email protected] W. Hou e-mail: [email protected] J. Liu e-mail: [email protected] Y. Liu e-mail: [email protected] C. Cheng e-mail: [email protected] M. J. Christensen Retired scientist of AgResearch, Grasslands Research Centre, Private Bag 11-008, Palmerston North 4442, New Zealand e-mail: [email protected] Y. Zhang Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, 350002 Fuzhou, China e-mail: [email protected]