State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, China.
Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Lanzhou University, Lanzhou, China.
Microbiol Spectr. 2024 Apr 2;12(4):e0257423. doi: 10.1128/spectrum.02574-23. Epub 2024 Mar 15.
The clavicipitaceous fungus forms symbiotic associations with drunken horse grass (), providing biotic and abiotic stress protection to its host. However, it is unclear how affects the assembly of host plant-associated bacterial communities after ammonium nitrogen (NH-N) treatment. We examined the shoot- and root-associated bacterial microbiota and root metabolites of when infected (I) or uninfected (F) with endophyte. The results showed more pronounced NH-N-induced microbial and metabolic changes in the endophyte-infected plants compared to the endophyte-free plants. significantly altered bacterial community composition and β-diversity in shoots and roots and increased bacterial α-diversity under NH-N treatment. The relative abundance of 117 and 157 root metabolites significantly changed with infection under water and NH-N treatment compared to endophyte-free plants. Root bacterial community composition was significantly related to the abundance of the top 30 metabolites [variable importance in the projection (VIP) > 2 and VIP > 3] contributing to differences between I and F plants, especially alkaloids. The correlation network between root microbiome and metabolites was complex. Microorganisms in the Proteobacteria and Firmicutes phyla were significantly associated with the R00693 metabolic reaction of cysteine and methionine metabolism. Co-metabolism network analysis revealed common metabolites between host plants and microorganisms.IMPORTANCEOur results suggest that the effect of endophyte infection is sensitive to nitrogen availability. Endophyte symbiosis altered the composition of shoot and root bacterial communities, increasing bacterial diversity. There was also a change in the class and relative abundance of metabolites. We found a complex co-occurrence network between root microorganisms and metabolites, with some metabolites shared between the host plant and its microbiome. The precise ecological function of the metabolites produced in response to endophyte infection remains unknown. However, some of these compounds may facilitate plant-microbe symbiosis by increasing the uptake of beneficial soil bacteria into plant tissues. Overall, these findings advance our understanding of the interactions between the microbiome, metabolome, and endophyte symbiosis in grasses. The results provide critical insight into the mechanisms by which the plant microbiome responds to nutrient stress in the presence of fungal endophytes.
内生真菌与醉马草（）形成共生关系，为宿主提供生物和非生物胁迫保护。然而，尚不清楚在铵态氮（NH-N）处理后，内生真菌如何影响宿主植物相关细菌群落的组装。我们检查了感染（I）或未感染（F）内生真菌的醉马草地上和地下部分相关的细菌微生物群和根代谢物。结果表明，与无内生真菌的植物相比，感染内生真菌的植物中 NH-N 诱导的微生物和代谢变化更为明显。内生真菌显著改变了地上和地下部分的细菌群落组成和β多样性，并在 NH-N 处理下增加了细菌α多样性。与无内生真菌的植物相比，在水和 NH-N 处理下，117 和 157 种根代谢物的相对丰度因内生真菌感染而显著变化。根细菌群落组成与解释 I 和 F 植物之间差异的前 30 种代谢物（变量重要性投影（VIP）>2 和 VIP>3）的丰度显著相关，特别是生物碱。根微生物组和代谢物之间的相关网络很复杂。在 Proteobacteria 和 Firmicutes 门的微生物与半胱氨酸和蛋氨酸代谢的 R00693 代谢反应显著相关。共代谢网络分析显示了宿主植物和微生物之间的共同代谢物。重要的是，我们的结果表明内生真菌感染的影响对氮的有效性很敏感。内生真菌共生改变了地上和地下细菌群落的组成，增加了细菌多样性。代谢物的类群和相对丰度也发生了变化。我们发现了根微生物和代谢物之间复杂的共现网络，一些代谢物在宿主植物与其微生物组之间共享。内生真菌感染后产生的代谢物的确切生态功能尚不清楚。然而，其中一些化合物可能通过增加有益土壤细菌进入植物组织来促进植物-微生物共生。总的来说，这些发现提高了我们对内生真菌共生的微生物组、代谢组和共生关系在禾本科植物中的相互作用的理解。这些发现为植物微生物组对真菌内生菌存在下营养胁迫的反应机制提供了关键见解。
