烟草短期连作对根际微生物和代谢物的影响

Effects of tobacco short-term continuous cropping on rhizosphere microorganisms and metabolites

【目的】进一步明确烟草连作障碍发生机理,探索烟草短期连作与根际微生物结构和根际代谢物之间的关系。【方法】采用Illumina高通量测序技术和超高效液相色谱串联四级杆飞行时间质谱技术,分析短期连作与未连作植烟根际土壤微生物组和代谢组多样性。【结果】根际细菌菌群多样性在不同品种间、连作与未连作组间均无显著差异,短期连作对根际细菌菌群结构和多样性影响不显著,但短期连作土壤中根际真菌丰度和均匀度显著降低,未连作根际真菌多样性显著高于短期连作根际真菌多样性。甘蓝油壶菌(Olpidium brassicae)、木贼镰刀菌(Fusarium equiseti)丰度在短期连作根际中显著增高,细长被孢霉菌(Mortierella elongata)丰度显著降低。LEfSe分析发现镰刀菌属(Fusarium)真菌为短期连作根际土壤中的标志物微生物。代谢组分析发现,有机氮化合物、鞘脂类、萜类、类固醇及其衍生物为短期连作与未连作植烟根际土壤间的显著差异代谢物。其中,游离氨基酸和小檗碱、茄定碱、酒糟碱等生物碱类物质在短期连作根际土壤中显著富集,表明短期连作过程中可能已经产生真菌感染和自毒效应。【结论】本研究初步解析了烟草短期连作下根际微生物和代谢物的相互关系,虽然短期连作对根际细菌群落的影响较小,但根际次生代谢物产生的化感作用能够快速且显著改变根际真菌菌群结构,导致致病真菌的快速繁殖。

【Objective】The present paper aimed to further clarify the mechanism of tobacco continuous cropping obstacles and explore the relationship between tobacco continuous cropping obstacles,rhizosphere microbial structure and rhizosphere metabolites.【Method】The study analyzed the microbiome and metabolome of short-term continuous cropping and non-continuous tobacco rhizosphere soil materials using Illumina high-throughput sequencing technology and UPLC-ATOF MS liquid-mass spectrometry technology.【Result】There was no significant difference in the diversity of rhizosphere bacteria among different varieties and between continuous cropping and non-continuous cropping soils.Short-term continuous cropping had no significant effect on the structure and diversity of rhizosphere bacteria,but the abundance and uniformity of rhizosphere fungal was significantly reduced along with the continuous cropping.The fungal diversity in the non-continuous cropping rhizosphere soil was significantly higher than that in the short-term continuous-cropping rhizosphere soil.The abundance of Olpidium brassicae and Fusarium equiseti increased significantly in short-term continuous cropping rhizosphere soil,while the abundance of Mortierella elongata decreased significantly.LEfSe showed that fungus in Fusarium were markers of significant difference between short-term continuous cropping and non-continuous tobacco rhizosphere soil.Metabolome analysis found that organic nitrogen compounds,sphingolipids,terpenoids,steroids and steroid derivatives were significantly different metabolites between short-term continuous cropping and non-continuous tobacco rhizosphere soil.Among them,the rhizosphere soil of short-term continuous cropping was significantly enriched in free amino acids and alkaloids such as berberine,solanine,and vinasse,indicating that fungal infection and autotoxic effects have been produced in the short-term continuous cropping tobacco rhizosphere soils.【Conclusion】The study preliminarily analyzed the relationship between rhizosphere microorganisms and metabolites under short-term continuous cropping of tobacco.Although short-term continuous cropping has little effect on the rhizosphere bacterial community,the allelopathic effect of rhizosphere secondary metabolites can quickly and significantly change the structure of rhizosphere fungal community,leading to rapid reproduction of pathogenic fungi.