Soil microbiota play vital roles in plant growth and resistance to stress, but how plants interact with root microbiomes to fight adverse environments remains elusive.土壤微生物在植物生长和抗逆性中发挥着重要作用，但植物如何与根系微生物组相互作用以应对不良环境仍不清楚。

摘要

（1）Soil salinization worldwide affects agroforestry, restraining output and functions of farmland and forest ecosystems. 全球范围内的土壤盐碱化影响着农林业，制约着农田和森林生态系统的产出和功能。

（2）Soil microbiota play vital roles in plant growth and resistance to stress, but how plants interact with root microbiomes to fight adverse environments remains elusive.土壤微生物在植物生长和抗逆性中发挥着重要作用，但植物如何与根系微生物组相互作用以应对不良环境仍不清楚。

（3）Here, we employed high-throughput sequencing to investigate the rhizobacterial community composition of three poplar varieties that were Populus davidiana × P. bolleana Loucne (SXY), P. deltoides × P. euramericana "Nanlin 895" (NL895), and P. alba × P. glandulosa "84K" (84K) under salt stress. 在此，我们采用高通量测序技术，研究了盐胁迫下三个杨树品种（SXY、NL895和84K）的根际细菌群落组成。

（4）Our results showed that no differences in growth parameters and damage indices were observed across varieties before treatments. 我们的结果表明，在处理之前，各品种之间的生长参数和损伤指数没有差异。

（5）Furthermore, SXY exhibited the highest salt tolerance, characterized by the highest growth parameters and lowest damage indices under salt stress, while NL895 was the most sensitive genotype.此外，SXY表现出最高的耐盐性，其特征是在盐胁迫下具有最高的生长参数和最低的损伤指数，而NL895是最敏感的基因型。

（6）The 16S rRNA gene sequencing unveiled the lowest diversity and distinct composition in the rhizobacterial community of SXY compared to other varieties.16S rRNA基因测序揭示，与其他品种相比，SXY的根际细菌群落多样性最低且组成独特。

（17）SXY accumulated a higher abundance of Pseudomonas, Pseudoxanthomonas, and Rhizobiaceae in the rhizosphere, which showed positive correlations with host salt tolerance.SXY在根际富集了更高丰度的假单胞菌属、假黄单胞菌属和根瘤菌科，这些微生物与宿主耐盐性呈正相关。

（18）Moreover, metabolomic analysis revealed higher levels of certain secondary metabolites in SXY roots than in the roots of the other varieties.此外，代谢组学分析显示，SXY根系中某些次生代谢物的水平高于其他品种。

（19）Four metabolites, including D-threitol, maslinic acid, 4',5-dihydroxy-7-methoxyflavanone, and trans-3-coumaric acid, were identified as key regulators that potentially mediate the enrichment of salt tolerance-associated rhizobacterial taxa.包括D-苏糖醇、马斯里酸、4',5-二羟基-7-甲氧基黄烷酮和反式-3-香豆酸在内的四种代谢物，被鉴定为可能介导耐盐相关根际细菌类群富集的关键调控因子。

（20）Our findings indicate an interaction between root metabolism and rhizosphere microbiome in poplar adaptation to salt stress, providing a theoretical basis for directional modulation of plant resistance under global change.我们的研究结果表明，在杨树适应盐胁迫过程中，根系代谢与根际微生物组之间存在相互作用，这为全球变化背景下植物抗性的定向调控提供了理论基础。

Figure 6总结了一个“植物-微生物协同耐盐”机制： 耐盐杨树品种SXY在盐胁迫下，根系合成并分泌四种特定代谢物（D-苏糖醇、马斯里酸、4',5-二羟基-7-甲氧基黄烷酮、反式-3-香豆酸），这些代谢物选择性招募根际中的有益细菌（假单胞菌属、根瘤菌科、假黄单胞菌属），被招募的细菌反过来促进根系生长、保护叶绿体、维护细胞膜完整性，从而共同增强杨树的耐盐性。

Result

（21）Divergent adaptation to salt stress across poplar varieties不同杨树品种对盐胁迫的分化适应

（22）Rhizobacterial community composition of poplar in saline soil 盐渍土壤中杨树根际细菌群落的组成

（23）Metabolome profiles of roots from poplar varieties under salt stress 盐胁迫下不同杨树品种根系的代谢组特征

（24）Interaction between rhizobacterial taxa and root metabolism in poplar salt tolerance 杨树耐盐性中根际细菌类群与根系代谢的相互作用

总结了一个“植物-微生物协同耐盐”机制： 耐盐杨树品种SXY在盐胁迫下，根系合成并分泌四种特定代谢物（D-苏糖醇、马斯里酸、4',5-二羟基-7-甲氧基黄烷酮、反式-3-香豆酸），这些代谢物选择性招募根际中的有益细菌（假单胞菌属、根瘤菌科、假黄单胞菌属），被招募的细菌反过来促进根系生长、保护叶绿体、维护细胞膜完整性，从而共同增强杨树的耐盐性