间作对大豆玉米根际微生物与根系代谢物的影响OA

To reveal the complex interaction relationship between root metabolites and rhizosphere microorganisms of soybean and maize under intercropping systems,field experiments were established with planting patterns including soybean monoculture,maize monoculture,and soybean and maize intercropping.During grain-filling stage of soybean(corresponding to the tasseling stage of maize),high-throughput detection technologies including 16S and ITS amplicon and non-targeted metabolomics were employed to analyze the effects of intercropping on the rhizosphere microbial diversity and relative abundance of soybean and maize under different planting patterns.The main differential metabolites in the root of soybean and maize under planting patterns including intercropping and monoculture were screened,and the interaction relationship between rhizosphere microorganisms and root metabolites was analyzed through correlation analysis.The results showed:1)soybean and maize intercropping significantly increased bacteria α-diversity index including Shannon,Simpson,Chao1 and ACE in soybean rhizosphere(P＜0.01),and reduced relative abundance of Bradyrhizobium and Fusarium in soybean rhizosphere(P＜0.001).2)A total of 534 differentially expressed metabolites(DEMs)were identified in soybean roots(194 up-regulated and 340 down-regulated)and 604 DEMs in maize roots(284 up-regulated and 320 down-regulated)were identified between intercropping and monocultures.DEMs in soybean root were mainly enriched in pathways such as amino acid biosynthesis,ABC transporters,and D-amino acid metabolism.DEMs in maize root are mainly enriched in pathways such as secondary metabolite biosynthesis,tryptophan metabolism and flavonoid biosynthesis.3)The relative abundance of Bradyrhizobium was significantly positively correlated(P＜0.05)with relative abundance of all DEMs in the soyMets Cluster Ⅰ group except for 1-{[3-(3,4-dihydroxyphenyl)acryloyl]oxy}-3,5-dihydroxycyclohexane-1-carboxylic acid,and showed an extremely significant negative correlation(P＜0.01)with relative abundance of all DEMs in the soyMets Cluster Ⅱ group except for 1-palmitoyl-2-(archidonoyl)-sn-glycero-3-phosphoethanolamine in soybean root.The relative abundance of Purpureocillium,Saitozyma and Badarisama showed a significant negative correlations(P＜0.05)with the relative abundance of DEMs in the mazMets ClusterⅠ group such as 2,3,4-trihydroxy-4-ethoxybenzophenone,showed a significant positive correlation(P＜0.05)with relative abundance of DEMs in the mazMets Cluster Ⅱ group such as Thr-Ala-Phe-Lys,in maize root.In conclusion,soybean and maize intercropping significantly increased bacteria diversity in soybean rhizosphere,significantly decreased the relative abundance of Bradyrhizobium and Fusarium in soybean rhizosphere.The relative abundance of Bradyrhizobium in the soybean rhizosphere was significantly related to DEMs in soybean root,while Purpureocillium,Saitozyma and Badarisama in the maize rhizosphere were significantly related to DEMs in maize roots.