施肥对马铃薯根组细菌群落多样性与功能的影响

Effects of fertilization on the bacterial diversity and functions of potato roots

摘要:

【背景】施肥是一种常用的农业生产手段，但目前关于施肥对马铃薯根系细菌群落多样性影响和对细菌功能影响的研究依然较少。【目的】以张家口地区马铃薯为研究对象，研究未施肥与常规施肥处理对马铃薯根系细菌组成结构和功能的影响。【方法】本研究利用16S rRNA基因高通量测序技术，对张家口马铃薯施肥与未施肥处理下根系微生物进行分析。【结果】施肥处理影响了马铃薯苗期与块茎形成期的根系细菌相对丰度：在苗期，相较于未施肥组，施肥组显著降低根际浮霉菌门(Planctomycetota)、根表蓝细菌门(Cyanobacteria)和根内厚壁菌门(Firmicutes)的相对丰度，显著提高根表蛭弧菌门(Bdellovibrionota)、装甲菌门(Armatimonadota)、拟杆菌门(Bacteroidota)、髌骨菌门(Patescibacteria)与根内绿弯菌门(Chloroflexi)、Planctomycetota的相对丰度；在块茎形成期，相较于未施肥组，施肥组显著提高根际的酸杆菌门(Acidobacteriota)、Firmicutes、放线菌门(Actinobacteriota)、Bacteroidota、Patescibacteria、根表的Armatimonadota、Bacteroidota、Bdellovibrionota和根内的Armatimonadota、念珠菌门(Hydrogenedentes)的相对丰度，显著降低根际Cyanobacteria、根表芽单胞菌门(Gemmatimonadota)、Cyanobacteria、黏球菌门(Myxococcota)和根内的硝化螺旋菌门(Nitrospirota)与RCP2-54的相对丰度。同时，施肥处理影响了马铃薯苗期与块茎形成期的基因功能相对丰度：在苗期，相较于未施肥组，施肥组显著提高根表其他次级代谢物的生物合成、糖类生物合成和代谢、复制与修复，以及根内复制与修复的基因功能相对丰度；在块茎形成期，相较于未施肥组，施肥组显著提高根际萜类和聚酮类化合物的代谢和脂质代谢、根内复制与修复，以及根表萜类和聚酮类化合物的代谢和脂质代谢的基因功能相对丰度，显著降低根际能量代谢、辅酶和维生素的代谢及其他氨基酸的代谢，以及根表转录、折叠、分类与降解和能量代谢的基因功能相对丰度。【结论】常规施肥能够改善其根系微生物结构和基因功能相对丰度，即相较于对照组，施肥组中细菌群落丰富度和多样性显著提高，并且有关代谢、能量转化与利用的基因功能相对丰度显著提高，从而有效地提高马铃薯产量。

关键词:马铃薯;常规施肥;根系微生物群

Abstract:

[Background] Fertilization is a common agronomic measure, while there are few studies about the effects of fertilization on the bacterial diversity and functions of potato roots. [Objective] To study the effects of non-fertilization and conventional fertilization on the community composition, structure, and function of bacteria in potato root samples collected from Zhangjiakou. [Methods] The 16S rRNA gene sequencing was employed to analyze the root bacteria of potato under fertilization and non-fertilization treatments. [Results] Fertilization affected the bacterial abundance of potato plants at the seedling stage and tuber formation stage. At the seedling stage, fertilization significantly reduced the abundance of Planctomycota, Cyanobacteria, and Firmicutes in the rhizosphere and significantly increased the abundance of Bdellovibrionota, Armatimonadota, Bacteroidota, and Patescibacteria on the root surface and the abundance of Chloroflexi and Planctomycetota in the roots, compared with non-fertilization treatment. At the tuber formation stage, fertilization significantly increased the abundance of Acidobacteriota, Firmicutes, Actinobacteriota, Bacteroidota, and Patescibacteria in the rhizosphere, Armatimonadota, Bacteroidota, and Bdellovibrionota on the root surface, and Armatimonadota and Hydrogenedentes in the roots. Meanwhile, it significantly decreased the abundance of Cyanobacteria in the rhizosphere, Gemmatimonadota, Cyanobacteria, and Myxococcota on the root surface, and Nitrospirota and RCP2-54 in the roots. In addition, fertilization affected the gene abundance of potato plants at the seedling stage and tuber formation stage. At the seedling stage, compared with non-fertilization treatment, fertilization significantly increased the abundance of genes involved in the biosynthesis of other secondary metabolites, glycan biosynthesis and metabolism, and replication and repair on the root surface and those for replication and repair in the roots. At the tuber formation stage, fertilization significantly increased the abundance of the genes associated with the metabolism of terpenoids and polyketides and lipid metabolism in the rhizosphere, replication and repair in the roots, and the metabolism of terpenoids and polyketides and lipid metabolism on the root surface. Meanwhile, it significantly reduced the abundance of genes involved in the energy metabolism, metabolism of cofactors and vitamins, metabolism of other amino acids in the rhizosphere and those participating in transcription, folding, sorting, degradation, and energy metabolism on the root surface. [Conclusion] Conventional fertilization could improve the root microbial structure and gene function abundance. That is, compared with the control group, fertilization increases the bacterial richness and diversity and the abundance of genes associated with the metabolism and energy conversion and utilization, thereby improving the potato yield.

Key words:potato;conventional fertilization;root microbiota