抗枯萎病香蕉品种宿根连作根际土壤微生物群落结构特征变化分析

Analysis of changes in rhizosphere soil microbial community structure of banana varieties resistant to wilt disease under continuous cropping

  • 摘要: 【目的】分析抗枯萎病香蕉品种宿根连作根际土壤微生物群落结构特征变化,为深入研究抗枯萎病香蕉品种宿根连作抗性增强的作用机制及利用生防微生物进行香蕉枯萎病绿色防控提供理论依据。【方法】以抗枯萎病香蕉品种宝岛蕉为试验材料,在枯萎病发病严重土壤上宿根连续种植3造:组培苗第一代(第1造)、宿根第一代(第2造)和宿根第二代(第3造),调查各造枯萎病发病率,四分法采集各造土壤样本并测定土壤化学性质;采集第1造健康和发病植株、第2和第3造健康植株的根际土壤样本,分别编号为S1、V、S2和S3,重复3次,利用Illumina高通量测序平台对12个土壤样本的细菌16Sr RNA和真菌ITS区进行测序分析;采用样本复杂度(Alpha多样性指数)、主坐标(PCoA)和UPGMA聚类分析土壤样本细菌和真菌群落的丰富度和多样性、门和属水平上的群落构成及相对丰度差异;通过Spearman分析优势微生物群落与镰刀菌属的相关性。【结果】抗枯萎病香蕉品种宝岛蕉连续种植3造根际土壤化学性质未发生明显改变,种植第3造的香蕉枯萎病发病率显著低于第1和第2造(P<0.05)。随着种植年限的增加,根际土壤细菌群落的多样性整体呈逐年下降趋势,而真菌群落的多样性整体呈逐年上升趋势。连作改变了香蕉根际土壤微生物的群落构成,S2和S3细菌和真菌的群落结构相近,明显与S1和V群落结构分离。S2和S3的壶菌门(Chytridiomycota)的相对丰度较S1分别低88.02%和89.51%,Fungi_phy_Incertae_sedis的相对丰度分别高41.56%和82.81%,S3镰刀菌属(Fusarium)的相对丰度较S1、S2分别低45.60%和50.47%,与留芽种植宿根蕉抗性表现增强相关。发病植株根际土壤中变形菌门(Proteobacteria)和担子菌门(Basidiomycota)的相对丰度较高,而酸杆菌门(Acidobacteriota)的相对丰度较低。球囊菌门(Glomeromycota)、毛霉门(Mucoromycota)、隐真菌门(Rozellomycota)和壶菌门(Chytridiomycota)的相对丰度均与镰刀菌呈负相关。【结论】宿根第3造蕉的发病率最低,其根际土壤与第1造发病植株根际土壤的细菌和真菌群落差异明显,推测根际土壤微生物群落丰富度、多样性和群落构成改变是抗枯萎病香蕉品种宿根连作抗性增强的原因。

     

    Abstract: 【Objective】To analyze the changes in soil microbial community structure in the rhizosphere of banana varieties resistant to wilt disease through continuous cropping, providing a theoretical basis for in-depth research on the mechanism of enhanced resistance of banana varieties to wilt disease through continuous cropping and the use of biocontrol microorganisms for green prevention and control of banana wilt disease. 【Method】The Fusarium wilt resistant banana variety Baodao banana was used as the experimental material, and the perennial roots were planted continuously for three generations on the soil with severe Fusarium wilt disease: the first generation of tissue culture seedlings(the first generation), the first generation of perennial roots(the second generation), and the second generation of perennial roots(the third generation). The incidence rate of Fusarium wilt of each generation was investigated, and the soil samples of each generation were collected by quartering method and the chemical properties of the soil were determined. Collected rhizosphere soil samples from healthy and diseased plants of the first generation, as well as healthy plants of the second and third generations, numbered as S1, V, S2 and S3, and repeated 3 times. Used Illumina high-throughput sequencing platform to sequence and analyze the bacterial 16S rRNA and fungal ITS regions of 12 soil samples; utilized sample complexity(Alpha diversity index), principal coordinates(PCoA), and UPGMA clustering analysis were used to analyze the richness and diversity of bacterial and fungal communities in soil samples, as well as differences in community composition and relative abundance at the phylum and genus levels; analyzed the correlation between dominant microbial communities and the Fusarium through Spearman correlation analysis. 【Result】The chemical properties of the rhizosphere soil of the banana variety Baodao banana with resistance to fusarium wilt did not change greatly after three successive generations of cultivation. The incidence rate of fusarium wilt of the third generation of banana was significantly lower than that of the first and second generation of banana(P<0.05). With the increase of planting years, the overall diversity of rhizosphere soil bacterial communities was decreasing year by year, while the overall diversity of fungal communities was increasing year by year. Continuous cropping changed the microbial community composition of banana rhizosphere soil, and the bacterial and fungal community structures in S2 and S3 were similar, clearly separated from those in S1 and V. The relative abundance of Chytridiomycota in S2 and S3 were 88.02% and 89.51% lower than that in S1 respectively, the relative abundance of Fungi_phy_Incertae_sedis phylum were 41.56% and 82.81% higher, respectively. The relative abundance of Fusarium in S3 was 45.60% and 50.47% lower than that in S1 and S2 respectively, which was related to the enhanced resistance performance of perennial banana planted with buds. The relative abundance of Proteobacteria and Basidiomycota in the rhizosphere soil of diseased plants was high, while the relative abundance of Acidobacteriota was low. The relative abundance of Glomeromycota, Mucoromycota, Rozellomycota, and Chytidiomycota was negatively correlated with Fusarium. 【Conclusion】The incidence rate of the third generation of banana is the lowest, and the bacterial and fungal communities in the rhizosphere soil are greatly different from those in the rhizosphere soil of the infected first generation of banana plant. It is speculated that the changes in the richness, diversity and composition of the microbial community in the rhizosphere soil are the reasons for the enhanced resistance of banana varieties to fusarium wilt.

     

/

返回文章
返回