Tibet Plateau Walnut Industry Research Institute / College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, 434025, China.
Faculty of Science, Department of Chemistry, University of Hradec Kralove, Hradec Kralove, 50003, Czech Republic.
BMC Plant Biol. 2023 Feb 28;23(1):118. doi: 10.1186/s12870-023-04111-3.
Arbuscular mycorrhizal fungi (AMF) have a positive effect on drought tolerance of plants after establishing reciprocal resymbiosis with roots, while the underlying mechanism is not deciphered. Metabolomics can explain the mechanism of plant response to environmental stress by analyzing the changes of all small molecular weight metabolites. The purpose of this study was to use Ultra High Performance Liquid Chromatography Q Exactive Mass Spectrometer to analyze changes in root metabolites of walnut (Juglans regia) after inoculation with an arbuscular mycorrhizal fungus Diversispora spurca under well-watered (WW) and drought stress (DS).
Sixty days of soil drought significantly inhibited root mycorrhizal colonization rate, shoot and root biomass production, and leaf water potential in walnut, while AMF inoculation significantly increased biomass production and leaf water potential, accompanied by a higher increase magnitude under DS versus under WW. A total of 3278 metabolites were identified. Under WW, AMF inoculation up-regulated 172 metabolites and down-regulated 61 metabolites, along with no changes in 1104 metabolites. However, under DS, AMF inoculation up-regulated 49 metabolites and down-regulated 116 metabolites, coupled with no changes in 1172 metabolites. Among them, juglone (a quinone found in walnuts) as the first ranked differential metabolite was up-regulated by AMF under WW but not under DS; 2,3,5-trihydroxy-5-7-dimethoxyflavanone as the first ranked differential metabolite was increased by AMF under DS but not under WW. The KEGG annotation showed a large number of metabolic pathways triggered by AMF, accompanied by different metabolic pathways under WW and DS. Among them, oxidative phosphorylation and phenylalanine metabolism and biosynthesis were triggered by AMF in response to WW and DS, where N-acetyl-L-phenylalanine was induced by AMF to increase under DS, while decreasing under WW.
This study provides new insights into the metabolic mechanisms of mycorrhiza-enhanced drought tolerance in walnuts.
丛枝菌根真菌（AMF）与根系建立互惠共生关系后，对植物的耐旱性有积极影响，但其潜在机制尚不清楚。代谢组学可以通过分析所有小分子代谢物的变化来解释植物对环境胁迫的反应机制。本研究旨在采用超高效液相色谱 Q Exactive 质谱联用仪分析在充分供水（WW）和干旱胁迫（DS）条件下，接种丛枝菌根真菌 Diversispora spurca 后，核桃（Juglans regia）根系代谢物的变化。
60 天的土壤干旱显著抑制了核桃的根内菌根定殖率、地上部和根生物量的产生以及叶片水势，而 AMF 接种显著增加了生物量的产生和叶片水势，并且在 DS 下的增幅大于 WW 下的增幅。共鉴定出 3278 种代谢物。在 WW 条件下，AMF 接种上调了 172 种代谢物，下调了 61 种代谢物，同时有 1104 种代谢物没有变化。然而，在 DS 条件下，AMF 接种上调了 49 种代谢物，下调了 116 种代谢物，同时有 1172 种代谢物没有变化。其中，胡桃醌（一种在核桃中发现的醌）作为第一个被上调的差异代谢物，在 WW 条件下被 AMF 上调，但在 DS 条件下没有被上调；2,3,5-三羟基-5-7-二甲氧基黄烷酮作为第一个被上调的差异代谢物，在 DS 条件下被 AMF 上调，但在 WW 条件下没有被上调。KEGG 注释显示 AMF 触发了大量的代谢途径，并且在 WW 和 DS 下存在不同的代谢途径。其中，氧化磷酸化和苯丙氨酸代谢和生物合成途径是由 AMF 响应 WW 和 DS 触发的，其中 N-乙酰-L-苯丙氨酸在 DS 下被 AMF 诱导增加，而在 WW 下则减少。
本研究为丛枝菌根增强核桃耐旱性的代谢机制提供了新的见解。
