Wang Ningqi, Ping Ling, Mei Xinlan, Zhang Yaozhong, Zhang Yuling, Yang Xinrun, Guo Yuting, Gao Yang, Xu Yangchun, Shen Qirong, Yang Tianjie, Wei Zhong
Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 211800, China.
Environ Microbiome. 2025 Jul 11;20(1):85. doi: 10.1186/s40793-025-00742-1.
Root exudates are key mediators in maintaining plant health by mediating interactions with the rhizosphere microbiome. Plants release specific exudates to defend against pathogens, either directly by inhibiting pathogen growth or indirectly through alterations in the microbial community. However, the mechanisms by which root exudates influence the rhizosphere microbiome to enhance plant resistance remain poorly understood. In this study, we evaluated the effects of 23 root exudates on the growth of the pathogen Ralstonia solanacearum and tomato bacterial wilt.
Seventeen of the exudates reduced the disease index, with most having neutral or even promotive effects on R. solanacearum growth. Notably, succinic acid (SA) completely suppressed bacterial wilt without directly affecting the pathogen or tomato plants in the absence of the rhizosphere microbiome. We further explored the impact of SA on the rhizosphere bacterial community in both tomato rhizosphere and bulk soil. Only the bacterial community in the rhizosphere responded significantly to SA addition, with indicator species and network analyses identifying Sphingomonas sp. WX113 as the key taxa associated with this response. A subsequent greenhouse experiment showed that co-applying Sphingomonas sp. WX113 with SA achieved 100% biocontrol efficiency, outperforming either treatment alone. In vitro assays further demonstrated that SA enhanced the antagonistic activity of Sphingomonas sp. WX113 against R. solanacearum.
Our findings emphasize the host-mediated role of root exudates, such as succinic acid, in selectively promoting beneficial Sphingomonas sp., thereby enhancing plant resistance to bacterial wilt. These results offer new perspectives on the combination of beneficial microbes and their matching compounds for soil-borne diseases management.
根系分泌物是通过介导与根际微生物群的相互作用来维持植物健康的关键介质。植物释放特定的分泌物来抵御病原体，要么直接抑制病原体生长，要么通过改变微生物群落间接抵御。然而，根系分泌物影响根际微生物群以增强植物抗性的机制仍知之甚少。在本研究中，我们评估了23种根系分泌物对病原菌茄科雷尔氏菌生长和番茄青枯病的影响。
17种分泌物降低了病情指数，其中大多数对茄科雷尔氏菌的生长具有中性甚至促进作用。值得注意的是，在没有根际微生物群的情况下，琥珀酸（SA）完全抑制了青枯病，而没有直接影响病原体或番茄植株。我们进一步探讨了SA对番茄根际和根际土壤中根际细菌群落的影响。只有根际细菌群落对添加SA有显著反应，通过指示物种和网络分析确定鞘氨醇单胞菌属WX113是与这种反应相关联的关键分类群。随后的温室实验表明，将鞘氨醇单胞菌属WX113与SA共同施用可实现100%的生物防治效率，优于单独的任何一种处理。体外试验进一步证明，SA增强了鞘氨醇单胞菌属WX113对茄科雷尔氏菌的拮抗活性。
我们的研究结果强调了根系分泌物（如琥珀酸）在宿主介导下的作用，即选择性促进有益的鞘氨醇单胞菌属生长，从而增强植物对青枯病的抗性。这些结果为有益微生物及其匹配化合物组合用于土传病害管理提供了新的视角。
