泓森槐促生菌对大豆生长的群落结构研究

Study on the Soybean Growth-Related Microbial Community Structure by Growth-Promoting Bacteria from Robinia pseudoacacia ‘Hongsen’

摘要: 大豆生产常受土传病害等因素制约，开发植物源有益微生物菌剂是实现大豆绿色提质增产的有效途径。泓森槐作为优良豆科树种，体内共生的内生菌蕴含大量功能微生物资源。系统挖掘泓森槐(Robinia pseudoacacia ‘Hongsen’)内生菌资源并评估其促生与生防潜力并筛选生物学功能较强的菌株进行大豆促生试验，基于16S rRNA基因测序技术探究其对大豆根际土壤细菌多样性和群落结构的影响。本研究从泓森槐根、茎、叶组织中分离获得138株内生菌，采用IS-PCR插入序列指纹图谱进行聚类分析，选取代表性菌株开展16S rRNA基因测序并构建系统发育树，结合生理生化测试与体外对抗试验分析其功能特性，并研究在大豆中施入泓森槐促生菌剂对土壤微生物多样性的影响。获得的菌株隶属于11个属28个种，其中芽孢杆菌属为优势菌群；多株菌株具备产酶(如纤维素酶、蛋白酶等)、溶磷解钾、合成长素等促生功能，并对茄镰孢菌(Fusarium solani)、立枯丝核菌(Rhizoctonia solani)及人参链格孢菌(Alternaria panax)表现出较强的抑菌活性。盆栽实验筛选出3株对大豆生长具有显著促进作用的菌株(HSH1、HSH81和HSH99)，其中HSH81综合效果最佳。基于16S rRNA高通量测序，接种功能菌后大豆根际细菌群落结构发生变化，以黄杆菌属(Flavobacterium)为主导菌群。泓森槐内生菌具有丰富的多样性和多功能性，在提升作物产量、改良土壤环境及绿色农业发展中具有重要应用潜力，泓森槐促生菌剂的施入使大豆根际细菌群落结构发生变化。

Abstract: Soybean production is often limited by soil-borne diseases and other factors. Developing plant-based beneficial microbial preparations is an effective way to achieve green quality improvement and yield increase for soybeans. Robinia pseudoacacia ‘Hongsen’, as a high-quality legume tree species, harbors endophytic bacteria that contain a large number of functional microbial resources. This study aims to systematically explore the endophytic microbial resources of Robinia pseudoacacia ‘Hongsen’, evaluate their plant growth-promoting (PGP) and biocontrol potential, screen strains with strong biological functions and conduct soybean growth-promoting experiments, and investigate their effects on rhizosphere bacterial diversity and community structure in soybean using 16S rRNA gene sequencing. A total of 138 endophytic strains were isolated from the roots, stems, and leaves of Robinia pseudoacacia ‘Hongsen’. IS-PCR fingerprinting was used for clustering analysis, representative strains were identified by 16S rRNA gene sequencing and phylogenetic analysis. Functional characteristics were assessed through physiological, biochemical, and in vitro antagonism assays. Pot experiments were conducted to evaluate the growth-promoting effects of selected strains on soybean, and high-throughput 16S rRNA sequencing was used to assess changes in rhizosphere microbial diversity. The isolates belonged to 28 species across 11 genera, with Bacillus as the dominant group. Several strains exhibited PGP traits such as enzyme production (e.g., cellulase, protease), phosphate solubilization, potassium mobilization, and auxin synthesis, and showed strong antagonistic activity against Fusarium solani, Rhizoctonia solani, and Alternaria panax. Three strains (HSH1, HSH81, HSH99) significantly promoted soybean growth in pot experiments, with HSH81 showing the best overall performance. High-throughput sequencing revealed that inoculation with functional strains altered the soybean rhizosphere bacterial community, with Flavobacterium emerging as the dominant genus. Endophytic bacteria from Robinia pseudoacacia ‘Hongsen’ harbors diverse and functionally rich endophytic bacteria with significant potential for improving crop yield, enhancing soil quality, and supporting sustainable agriculture. Application of its PGP strains notably reshaped the soybean rhizosphere bacterial community structure.