微生物组与代谢组联合分析解淀粉芽孢杆菌对水分亏缺下马铃薯的促生效应

Growth promotion effects of Bacillus amyloliquefaciens on potato under water deficit by combining microbiome and metabolome

【目的】探究水分亏缺下马铃薯接种解淀粉芽孢杆菌B9601-Y2对其根部生长代谢、根际细菌结构多样性的影响,为微生物与植物互作及诱导植物对干旱产生耐受性提供理论依据。【方法】以1株解淀粉芽孢杆菌B9601-Y2及对水分亏缺敏感的马铃薯品种滇薯1418为材料,设定4个处理:BD处理,水分亏缺,接菌,土壤相对湿度(45±5)%;BCK处理,正常供水条件,接菌,土壤相对湿度(75±5)%;对照(CK),正常供水条件,未接菌;D处理,水分亏缺,未接菌(空白对照)。测定各处理的菌株定殖情况,采用广泛靶向代谢组学技术及基于Illumina NovaSeq测序技术对马铃薯根部代谢物、土壤细菌多样性及相对丰度进行分析。【结果】B9601-Y2菌株能在水分亏缺条件下的马铃薯根部定殖,定殖率为65.71%,微生物处理因素对马铃薯根系活力、根冠比均有极显著影响(P<0.01,下同)。根际细菌多样性结果显示,通过分类操作单元(OTU)聚类共获得7538个OTUs,水分亏缺下接菌处理(BD处理)提高了类诺卡氏菌属(Nocardioides)和大理石雕菌属(Marmoricola)的相对丰度。根部差异代谢物主要集中在氨基酸的生物合成途径,其中,氨基酸类差异代谢物受不同水分处理影响的有5种、受不同接菌处理影响的有3种。经微生物组与代谢组联合分析,水分亏缺条件下接菌处理(BD处理)存在酸微菌属(Iamia)与N-甲酰-L-蛋氨酸、L-γ-谷氨酰胺-L-亮氨酸均呈极显著正相关,接菌处理(BCK和BD处理)均存在假诺卡氏菌属(Pseudonocardia)、大理石雕菌属和类诺卡氏属与L-甲硫氨酸、L-脯氨酸呈极显著正相关。【结论】水分亏缺条件下的马铃薯根部定殖解淀粉芽孢杆菌B9601-Y2,使其根系活力与根冠比增加,改变根际细菌结构及其相对丰度,优势菌属与氨基酸类差异代谢物的密切互作对马铃薯有促生效果,使其对干旱的耐受性提升。

【Objective】This paper investigated the effects of Bacillus amyloliquefaciens B9601-Y2 inoculation on root growth metabolism and rhizosphere bacterial structural diversity of potato under water deficit,so as to provide a theoretical basis for the interaction between microorganisms and plants and the induction of drought tolerance in plants.【Method】Astrain of B.amyloliquefaciens B9601-Y2 and a water-deficit sensitive potato variety Dianshu 1418 were used as materials.Four treatment groups were set:BD:inoculation treatment under water deficit condition with soil relative humidity(45±5)%;BCK:inoculation treatment under normal water supply condition with soil relative humidity(75±5)%;control(CK):normal water supply condition without inoculation treatment;D:water deficit condition without inoculation treatment(blank control).The colonization of strains in each treatment was measured.Extensive targeted metabolomics technology and Illumina NovaSeq sequencing technology were used to analyze the diversity and relative abundance of potato root metabolites and soil bacteria.【Result】B9601-Y2 could colonize potato roots under water deficit condition,with a colonization rate of 65.71%.Microbial treatment had extremely significant effects on potato root activity and root-shoot ratio(P<0.01,the same below).According to rhizosphere bacterial diversity,a total of 7538 operational taxonomic unit(OTU)were obtained by OTU clustering.BD increased the relative abundance of Nocardioides and Marmoricola.The differential metabolites in roots were mainly concentrated in amino acid biosynthesis pathway.Among them,5 amino acid differential metabolites were affected by different water treatments,and 3 amino acid differential metabolites were affected by different bacterial inoculation treatments.The combined analysis of microbiome and metabolome showed that Iamia was extremely significantly positively correlated with N-formyl-L-methionine and L-γ-glutamine-L-leucine in BD.In BCK and BD treatments,Pseudonocardia,Marmoricola and Nocardioides were extremely significantly positively correlated with L-methionine and L-proline.【Conclusion】B.amyloliquefaciens B9601-Y2 can be colonized in potato roots under water deficit condition,which can increase root activity and root-shoot ratio,change the structure and relative abundance of bacteria in the rhizosphere.The close interaction between dominant bacteria and differential metabolites of amino acids can promote potato growth and improve its tolerance to drought.