Table 4_A multi-omics approach to unravel the interaction between heat and drought stress in the Arabidopsis thaliana holobiont.xlsx

The impact of combined heat and drought stress was investigated in Arabidopsis thaliana and compared to individual stresses to reveal additive effects and interactions. A combination of plant metabolomics and root and rhizosphere bacterial metabarcoding were used to unravel effects at the plant holobiont level. Hierarchical cluster analysis of metabolomics signatures pointed out two main clusters, one including heat and combined heat and drought, and the second cluster that included the control and drought treatments. Overall, phenylpropanoids and nitrogen-containing compounds, hormones and amino acids showed the highest discriminant potential. A decrease in alpha-diversity of Bacteria was observed upon stress, with stress-dependent differences in bacterial microbiota composition. The shift in beta-diversity highlighted the pivotal enrichment of Proteobacteria, including Rhizobiales, Enterobacteriales and Azospirillales. The results corroborate the concept of stress interaction, where the combined heat and drought stress is not the mere combination of the single stresses. Intriguingly, multi-omics interpretations evidenced a good correlation between root metabolomics and root bacterial microbiota, indicating an orchestrated modulation of the whole holobiont.

本研究以拟南芥（Arabidopsis thaliana）为实验材料，探究高温干旱复合胁迫的影响，并与单一胁迫处理进行对比，以揭示其加性效应与互作机制。本研究结合植物代谢组学、根系与根际细菌元条形码测序技术，旨在解析胁迫对植物全共生体（holobiont）层面的影响。对代谢组特征开展层级聚类分析后，结果显示两大主要聚类簇：其一涵盖高温胁迫组与高温干旱复合胁迫组，其二则包含对照组与干旱胁迫组。总体而言，苯丙烷类化合物、含氮化合物、激素及氨基酸展现出最高的判别潜力。胁迫处理下细菌的α多样性（alpha-diversity）出现显著下降，且细菌菌群组成呈现胁迫依赖性差异。β多样性（beta-diversity）的变化则凸显出变形菌门（Proteobacteria）的关键富集，其中包括根瘤菌目（Rhizobiales）、肠杆菌目（Enterobacteriales）与固氮螺菌目（Azospirillales）。本研究结果证实了胁迫互作的核心概念：高温干旱复合胁迫并非单一胁迫的简单叠加。值得注意的是，多组学分析结果显示根系代谢组与根系细菌菌群之间存在良好的相关性，表明整个植物全共生体受到了协同调控。