文章标题：Nitrogen supply mediated the effects of Epichloë endophytes on the growth and secondary metabolism of Achnatherum sibiricum
作者列表：Qin Tianzi, Shi Xinjian, Li Nannan, Hou Yanwei, Wu Zhengqin, Chen Lei, Zhao Nianxi, Gao Yubao, Ren Anzh
期刊：PLANT AND SOIL
发表时间：2026-1-7
影响因子：4.1
DOI:10.1007/s12015-026-11066-z
主要研究成果：Abstract
Background and aims
Natural grasslands are often nitrogen-limited. Even slight variations in nitrogen levels can significantly alter plants and microbial growth, and their interactions. While Epichloë endophytes are well-documented to promote host plant growth, it remains unclear how nitrogen availability modulates the effects of endophyte infection on host plant growth and metabolism.
Methods
In this study, we used endophyte-infected (E +) and endophyte-free (E-) Achnatherum sibiricum to investigate the effects of endophyte infection on host growth and metabolism under low (0.5 mM N), moderate (7.5 mM N), and high (12.5 mM N) nitrogen conditions.
Results
Epichloë endophytes conferred the most pronounced positive effects on host plants under moderate nitrogen conditions. Specifically, Epichloë upregulated genes involved in nitrogen transport and assimilation, photosynthesis, and indole-3-acetic acid (IAA) biosynthesis, leading to increased levels of total carbon, amino acids, and IAA. These changes stimulated biomass production and secondary metabolites (total phenolics and total alkaloids). Under low nitrogen, although E + plants showed upregulation of nitrogen assimilation and photosynthetic genes, this did not enhance plant growth, but did promote the accumulation of total phenolics and total alkaloids. Under high nitrogen, the promotional effect of Epichloë endophytes on nitrogen metabolism and photosynthesis genes was attenuated; while IAA levels remained elevated in E + plants compared to E- plants, Epichloë led only to an increase in total alkaloids accumulation, without promoting plant growth.
