已知MdUGT88F1介导的根皮苷生物合成可增强抗病性，但其在塑造根际微生物组以及赋予对Fpmd MR5抗性方面的作用尚不清楚。

MdUGT88F1 enhances plant resistance to Fusarium proliferatum f.sp. malus domestica MR5 via root exudate-mediated assembly of disease-suppressive rhizosphere microbiota

摘要

（1）Apple replant disease (ARD) is a major threat to the sustainable development of China's apple industry.苹果再植病是中国苹果产业可持续发展面临的主要威胁。

（2）It is primarily caused by the accumulation of phloridzin and the pathogen Fusarium proliferatum f.sp. malus domestica MR5 (Fpmd MR5). 该病主要由根皮苷的积累和病原菌芬芳镰刀菌苹果专化型MR5（Fpmd MR5）引起。

（3）MdUGT88F1-mediated phloridzin biosynthesis is known to enhance disease resistance, but its role in shaping the rhizosphere microbiome and conferring resistance against Fpmd MR5 remains unclear. 已知MdUGT88F1介导的根皮苷生物合成可增强抗病性，但其在塑造根际微生物组以及赋予对Fpmd MR5抗性方面的作用尚不清楚。

（4）In this study, we used wild-type (WT) and MdUGT88F1 transgenic apple lines to systematically investigate the mechanism by which MdUGT88F1 regulates the rhizosphere microbiome to mitigate ARD. 在本研究中，我们利用野生型和MdUGT88F1转基因苹果株系，系统研究了MdUGT88F1调控根际微生物组以减轻苹果再植病的机制。

（5）Compared with WT and MdUGT88F1-OE plants, MdUGT88F1-RNAi plants exhibited enhanced tolerance to ARD, as indicated by reduced disease severity, decreased abundance of Fpmd MR5 in the rhizosphere soil, and lower phloridzin content. 与野生型和MdUGT88F1过表达植株相比，MdUGT88F1-RNAi植株表现出对苹果再植病增强的耐受性，表现为病害严重度降低、根际土壤中Fpmd MR5丰度减少以及根皮苷含量下降。

（6）Further greenhouse experiments demonstrated that the rhizosphere bacterial communities were triggered mainly by changes in community composition.进一步的温室实验表明，根际细菌群落的改变主要是由群落组成的变化引起的。

（7）Multi-omics joint analysis revealed that members of the family Bacillaceae with multiple plant growth-promoting traits were enriched in the MdUGT88F1-RNAi plant rhizosphere but only upon Fpmd MR5 invasion.多组学联合分析显示，具有多种促生性状的芽孢杆菌科成员在MdUGT88F1-RNAi植株根际中富集，但仅当Fpmd MR5侵染时才发生。

（8）MdUGT88F1-RNAi plants exhibited significantly higher exudation of D-tagatose, D-galactose, sucrose, 3-O-methyl-D-glucose, and maltitol. MdUGT88F1-RNAi植株分泌的D-塔格糖、D-半乳糖、蔗糖、3-O-甲基-D-葡萄糖和麦芽糖醇显著增加。

（9）Interestingly, exogenous application of these compounds promoted the proliferation of Bacillus, enhancing plant resistance to Fpmd MR5.有趣的是，外源施用这些化合物促进了芽孢杆菌的增殖，从而增强了植株对Fpmd MR5的抗性。

（10） In vitro assays demonstrated that the recruited Bacillus significantly inhibited the hyphal growth and fumonisin B1 production of Fpmd MR5 and alleviated plant disease symptoms.体外实验表明，被招募的芽孢杆菌显著抑制了Fpmd MR5的菌丝生长和伏马菌素B1的产生，并减轻了植株病害症状。

（11） We experimentally validated this observation by inoculating a synthetic microbial community (Bacillus velezensis, Bacillus mojavensis, Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus licheniformis) into replanted soil, which led to a significant reduction in pathogen Fusarium abundance and promoted plant growth. 我们通过将合成微生物群落（贝莱斯芽孢杆菌、莫哈韦芽孢杆菌、枯草芽孢杆菌、解淀粉芽孢杆菌和地衣芽孢杆菌）接种到再植土壤中，实验验证了这一观察结果，这导致了病原镰刀菌丰度的显著降低并促进了植株生长。

（12）Overall, these findings highlight that plant disease resistance is a complex trait driven by dynamic interactions among the host genetic background, rhizospheric microbial communities, and pathogens.总体而言，这些发现强调了植物抗病性是一个受宿主遗传背景、根际微生物群落和病原菌之间动态相互作用驱动的复杂性状。

（13）Targeted modulation of the rhizospheric microbiome represents a potent "prebiotic" strategy. 靶向调控根际微生物组代表了一种有效的“益生元”策略。

（14）This approach can indirectly enhance plant disease resistance by fostering beneficial microbial activity in the rhizosphere.这种方法可以通过促进根际中有益微生物的活性来间接增强植物抗病性。

（15）This study also provides a theoretical basis and practical solutions for the green control of ARD through prebiotics and synthetic microbial communities. 本研究也为通过益生元和合成微生物群落绿色防控苹果再植病提供了理论基础和实践方案。

图C 先用化合物（ACs/FCs/水）处理土壤60天，让土壤微生物组“适应”不同的碳源；然后取这些土壤的悬液（含微生物）或无菌滤液（无微生物），加到种有植物的盆中，再接种病原菌，观察哪些处理能抑制病害。关键发现是：含微生物的FCs土壤悬液能抑病，无菌滤液不能抑病——证明是微生物介导的抗病，而不是化合物本身直接杀菌。

图C的实验流程

（16）结果

（17）ARD tolerance of MdUGT88F1-RNAi plants MdUGT88F1-RNAi植株对苹果再植病的耐受性

（18）MdUGT88F1 was involved in microbe-mediated disease resistance.MdUGT88F1参与了微生物介导的抗病性。

（19）Rhizosphere microbiota associated with OE and RNAi plants show apparent compositional and functional differences与过表达和RNAi植株相关的根际微生物群表现出明显的组成和功能差异

（20）Community shifts of rhizosphere bacteria and fungi under Fpmd MR5 inoculation in pot experiments盆栽实验中Fpmd MR5接种下根际细菌和真菌的群落变化

（21） Functional response of rhizosphere bacteria under Fpmd MR5 inoculation  Fpmd MR5接种下根际细菌的功能响应

（22）MdUGT88F1-mediated suppressive microbiota was associated with varied root exudates  MdUGT88F1介导的抑病微生物群与根系分泌物的变化相关

（23）Root exudatesare involved in disease suppression via the recruitment of disease-suppressing Bacillus species 根系分泌物通过招募抑病芽孢杆菌参与病害抑制

（24） Pathogen suppressiveness of the responsive taxa 响应类群对病原菌的抑制能力

 与野生型和MdUGT88F1过表达植株相比，MdUGT88F1-RNAi植株表现出对苹果再植病增强的耐受性，表现为病害严重度降低、根际土壤中Fpmd MR5丰度减少以及根皮苷含量下降。