Sang Yinghua, Ren Ke, Chen Yi, Wang Bin, Meng Yufang, Zhou Wenbing, Jiang Yonglei, Xu Junju
College of Tobacco Science, Yunnan Agricultural University, Kunming, China.
Yunnan Academy of Tobacco Agricultural Sciences, Yuxi, China.
Front Microbiol. 2024 Aug 23;15:1455880. doi: 10.3389/fmicb.2024.1455880. eCollection 2024.
Tobacco root-knot nematode (TRKN) disease is a soil-borne disease that presents a major hazard to the cultivation of tobacco, causing significant reduction in crop quality and yield, and affecting soil microbial diversity and metabolites. However, differences in rhizosphere soil microbial communities and metabolites between healthy tobacco soils and tobacco soils with varying degrees of TRKN infection remain unclear.
In this study, diseased rhizosphere soils of tobacco infected with different degrees of TRKN [severally diseased (DH) soils, moderately diseased (DM) soils, and mildly diseased (DL) soils] and healthy (H) rhizosphere soils were collected. Here, we combined microbiology with metabolomics to investigate changes in rhizosphere microbial communities and metabolism in healthy and TRKN-infected tobacco using high-throughput sequencing and LC-MS/MS platforms.
The results showed that the Chao1 and Shannon indices of bacterial communities in moderately and mildly diseased soils were significantly higher than healthy soils. The Proteobacteria, Actinobacteria, Ascomycota, Burkholderia, and were enriched in the rhizosphere soil of healthy tobacco. Basidiomycota, Agaricales, Pseudeurotiaceae and were enriched in severally diseased soils. Besides, healthy soils exhibited a relatively complex and interconnected network of bacterial molecular ecologies, while in severally and moderately diseased soils the fungal molecular networks are relatively complex. Redundancy analysis showed that total nitrogen, nitrate nitrogen, available phosphorus, significantly affected the changes in microbial communities. In addition, metabolomics results indicated that rhizosphere soil metabolites were significantly altered after tobacco plants were infected with TRKNs. The relative abundance of organic acids was higher in severally diseased soils. Spearman's analyses showed that oleic acid, C16 sphinganine, 16-hydroxyhexadecanoic acid, D-erythro-3-methylmalate were positively correlated with Basidiomycota, Agaricales, .
In conclusion, this study revealed the relationship between different levels of TRKN invasion of tobacco root systems with bacteria, fungi, metabolites and soil environmental factors, and provides a theoretical basis for the biological control of TRKN disease.
烟草根结线虫病是一种土传病害，对烟草种植构成重大危害，导致作物品质和产量大幅下降，并影响土壤微生物多样性和代谢产物。然而，健康烟草土壤与不同程度感染烟草根结线虫的土壤之间根际土壤微生物群落和代谢产物的差异仍不清楚。
本研究采集了不同程度感染烟草根结线虫的患病烟草根际土壤[重病（DH）土壤、中度病（DM）土壤和轻度病（DL）土壤]以及健康（H）根际土壤。在此，我们结合微生物学和代谢组学，使用高通量测序和LC-MS/MS平台研究健康和感染烟草根结线虫的烟草根际微生物群落和代谢的变化。
结果表明，中度和轻度病土壤中细菌群落的Chao1和Shannon指数显著高于健康土壤。变形菌门、放线菌门、子囊菌门、伯克霍尔德菌属等在健康烟草根际土壤中富集。担子菌门、伞菌目、假散囊菌科等在重病土壤中富集。此外，健康土壤表现出相对复杂且相互关联的细菌分子生态网络，而在重病和中度病土壤中真菌分子网络相对复杂。冗余分析表明，全氮、硝态氮、有效磷显著影响微生物群落的变化。此外，代谢组学结果表明，烟草植株感染烟草根结线虫后，根际土壤代谢产物发生显著改变。重病土壤中有机酸的相对丰度较高。Spearman分析表明，油酸、C16鞘氨醇、16-羟基十六烷酸、D-赤藓糖-3-甲基苹果酸与担子菌门、伞菌目等呈正相关。
总之，本研究揭示了烟草根结线虫对烟草根系不同程度入侵与细菌、真菌、代谢产物和土壤环境因素之间的关系，为烟草根结线虫病的生物防治提供了理论依据。
