四川三台县麦冬//玉米间作体系根际微生物多样性及功能分析

Biodiversity and functions of rhizosphere microbiome in the Ophiopogon japonicus-maize intercropping system in Santai County, Sichuan Province

摘要:

【背景】麦冬//玉米间作是麦冬产区最主要的种植模式，解析该模式根际土壤微生物群落及功能，为利用栽培措施改良土壤生态环境及从土壤微生态学角度揭示麦冬//玉米间作生态种植机理提供理论依据。【目的】明确麦冬//玉米间作体系下根际土壤微生物群落结构及功能。【方法】分别采集单作与间作麦冬、玉米根际土壤，采用Illumina-NovaSeq高通量测序技术对根际土壤中微生物群落结构和功能进行分析。【结果】间作显著提高麦冬株高及产量，而对玉米则影响较小。间作条件下，麦冬、玉米根际土壤细菌多样性与单作无显著差异，但麦冬根际真菌多样性提高，玉米根际真菌多样性降低。与单作相比，间作使麦冬根际放线菌门(Actinobacteriota)、被孢霉门(Mortierellomycota)、Xenomyrothecium和赤霉属(Gibberella)的相对丰度降低，而富集了子囊菌门(Ascomycota)、毛霉菌门(Mucoromycota)、拟棘壳孢属(Pyrenochaetopsis)、根霉属(Rhizopus)、镰刀菌属(Fusarium)、链格孢属(Alternaria)、溶杆菌属(Lysobacter)和罗河杆菌属(Rhodanobacter)等。间作使玉米根际子囊菌门、脱硫杆菌门(Desulfobacterota)、粘菌门(Myxococcota)、小鬼伞属(Coprinellus)和镰刀菌属的相对丰度增加，枝孢菌科(Cladosporiaceae)等10个科、Xenomyrothecium和赤霉属的数量则显著减少。在3种KEGG水平上，单、间作麦冬和玉米根际微生物各代谢通路的相对丰度均无显著性差异。间作使植物病原菌、土壤腐生生物和木质腐生生物共存功能群显著富集在麦冬和玉米根际，间作显著降低了寄生真菌功能群在玉米根际的相对丰度，而在麦冬根际中则显著提高。此外，间作条件下，植物病原菌功能群相对丰度在玉米根际显著降低，在麦冬根际则显著提高。【结论】麦冬//玉米间作促进麦冬生长，提高麦冬产量，对麦冬、玉米根际细菌群落结构和功能的影响较小，大部分菌属均无显著性差异，而真菌群落结构和功能则受种间互作的影响较大，大多数菌属表现出趋同和趋异显著性变化。

Abstract:

[Background] Ophiopogon japonicus-maize intercropping is the main planting mode in Ophiopogonis Radix producing areas. Revealing the microbiome structure and functional changes in the rhizosphere soil of this mode is crucial for ecological intercropping. [Objective] To investigate the diversity and functions of rhizosphere microbiome in the O. japonicus-maize intercropping system. [Methods] We employed Illumina-NovaSeq high-throughput sequencing of the 16S rRNA gene of bacteria and the ITS rDNA of fungi to study the microbiome structure and functions in the rhizosphere soil samples of the O. japonicus-maize intercropping system and monoculture systems. [Results] Intercropping significantly increased the plant height and yield of O. japonicus but had little effect on maize. The bacterial diversity in rhizosphere soil of both plants had no significant difference between intercropping and monoculture patterns. However, compared with monoculture, intercropping increased the fungal diversity in the rhizosphere soil of O. japonicus and decreased the fungal diversity in the rhizosphere soil of maize. Compared with monoculture, intercropping reduced the relative abundance of Actinobacteriota, Mortierellomycota, Xenomyrothecium, and Gibberella but enriched Ascomycota, Mucoromycota, Pyrenochaetopsis, Rhizopus, Fusarium, Alternaria, Lysobacter, and Rhodanobacter in the rhizosphere of O. japonicus. In the rhizosphere of maize, intercropping increased the relative abundance of Ascomycota, Desulfobacterota, Myxococcota, Coprinellus, and Fusarium, while decreasing the relative abundance of ten families including Cladosporiaceae and two genera of Xenomyrothecium and Gibberella. No significant differences were observed in the relative abundance of KEGG pathways of rhizosphere microbiome between monoculture and intercropping modes. Intercropping significantly increased the relative abundance of plant pathogens, soil saprotrophs, and wood saprotrophs in the rhizosphere of both O. japonicus and maize. However, it decreased the relative abundance of fungal parasites in the rhizosphere of maize while increasing that in the rhizosphere of O. japonicus. Furthermore, intercropping reduced the relative abundance of plant pathogens in the rhizosphere of maize but significantly increased that in the rhizosphere of O. japonicus. [Conclusion] The intercropping of O. japonicus and maize promotes the growth and increases the yield of O. japonicus. It has mild effects on the structure and functions of rhizosphere bacterial community of O. japonicus and maize, and most bacterial genera displayed no significant difference between the two cropping modes. However, the structure and functions of fungal community were greatly influenced by intercropping, and most fungal genera showed significant convergence or divergence.