白菜健康株与根肿病患病株的土壤微生物群落和功能差异

Differences in soil microbial community and function between healthy and clubroot diseased plants of Chinese cabbage

  • 摘要: 根肿病严重制约着十字花科蔬菜产业的发展, 而土壤微生物多样性与组成的变化不仅与十字花科作物根肿病密切相关, 且对土壤健康、农业生产系统的可持续发展和人体健康至关重要。因此, 了解十字花科根肿病发生与土壤微生物群落结构的关系十分必要。采用Illumina MiSeq高通量测序技术对白菜健康株和患根肿病病株的根围土壤的细菌16S rDNA和真菌ITS序列进行测序, 将结果质控后与相关数据库进行比对; 测定了根围土壤理化性质, 分析了样本间的微生物群落结构与组成差异, 探讨土壤理化、土壤微生物群落和根肿病间的关系; 并对样本细菌和真菌功能进行了预测。结果表明: 1)健康白菜植株根围土壤细菌群落均匀度及多样性程度均高于患根肿病植株, 患根肿病白菜植株根围土壤真菌群落丰富度、均匀性和多样性程度均高于健康白菜植株根围土壤。2)放线菌门(Actinobacteria)、变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)和芽单胞菌门(Gemmatimonadetes)是所测土壤样本中的主要优势细菌门, 芽孢杆菌属(Bacillus)、GaiellaDefluviicoccus、梭状芽孢杆菌属(Clostridium)和类诺卡氏属(Nocardioides)是所测土壤样本中的主要优势细菌属; 根围土壤优势真菌类群为子囊菌门(Ascomycota)、被孢霉门(Mortierellomycota)、担子菌门(Basidiomycota)和壶菌门(Olpidiomycota), 主要的真菌属为赤霉属(Gibberella)、被孢霉属(Mortierella)、梭孢壳属(Thielavia)和Basipetospora。3)新陈代谢、环境信息处理、细胞过程和有机系统是健康株与患病株根围土壤细菌群落具有显著差异的4类细菌功能; 患根肿病植株根围土壤真菌群落中赤霉属、梭孢壳属、丝壳属(Kernia)和镰刀菌属(Fusarium)的功能丰度均大于健康株。4)主坐标分析结果表明健康植株与患根肿病植株根围土壤细菌和真菌群落结构差异明显, 冗余分析结果显示, pH、全氮、碱解氮、速效钾和阳离子交换量是根围土壤微生物群落变化的主要影响因素。白菜健康株与根肿病患病株根围土壤中真菌群落的差异比细菌群落大。本文为研究十字花科作物微生物区系提供了新的依据, 并为研究有益合成菌群抑制病原菌从而控制根肿病的方法提供了可能性, 同时也为缓解土壤退化和重建健康土壤提供了途径。

     

    Abstract: Clubroot disease severely restricts the development of the cruciferous vegetables industry. Changes in soil microbial diversity and composition are not only closely related to cruciferous crop clubroot disease but are also crucial to soil health, sustainable development of agricultural production systems, and human health. Therefore, it is necessary to understand the differences in microbial community structure between clubroot and bulk soil. Illumina MiSeq high-throughput sequencing technology was used to sequence bacterial 16S rDNA and fungal ITS genes in the bulk soil of healthy (H) and clubroot infected (D) Chinese cabbage. The results were compared with relevant databases after quality control. The physical and chemical properties of the bulk soil were determined, and the differences in the microbial community structure and composition between samples were analyzed. The relationship between soil physical and chemical properties, soil microbial community, and clubroot disease was discussed, and the function of bacteria and fungi in the samples was predicted. The results showed that: 1) the evenness and diversity of the bacterial community in the bulk soil of healthy Chinese cabbage plants were higher than those in the bulk soil of Chinese cabbage plants with clubroot disease. The richness, evenness, and diversity of fungal communities in the bulk soil of Chinese cabbage plants with clubroot disease were higher than those in the bulk soil of healthy Chinese cabbage plants, indicating that clubroot disease greatly influenced the composition of the soil fungal community. 2) Actinobacteria, Proteobacteria, Firmicutes, Chloroflexi, Acidobacteria, and Gemmatimonadetes were the dominant phyla of bacteria in soil samples. Bacillus, Gaiella, Defluviicoccus, Clostridium, and Nocardioides were the dominant genera of bacteria in the soil samples. The dominant fungal phyla in the bulk soil were Ascomycota, Mortierellomycota, Basidiomycota, and Olpidiomycota. The main fungal genera identified were Gibberella, Mortierella, Thielavia, and Basipetospora. 3) Metabolism, environmental information processing, cellular processes, and organic systems are four types of bacterial functions with significant differences in bulk soil bacterial communities between healthy and diseased plants; the functional abundances of Gibberella, Thielavia, Kernia, and Fusarium in bulk soil fungal communities of diseased plants were higher than those of healthy plants. 4) Principal coordinate analysis showed that the bacterial and fungal community structures in the bulk soil of healthy and diseased plants were significantly different. Redundant analysis showed that pH, total nitrogen, available nitrogen, available potassium, and cation exchange capacity were the main factors influencing microbial community changes in bulk soil. This study provides a new basis for the study of rhizosphere microbial flora of cruciferous crops and provides the possibility for the study of the method of controlling clubroot by beneficial synthetic bacteria-mediated pathogenic bacteria, as well as a way to alleviate soil degradation and rebuild healthy soil.

     

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