香石竹设施栽培根际土壤微生物区系的16SrRNA系统遗传多样性

Distribution of microbes and their hereditary diversity in the rhizosphere of carnation in greenhouse

【目的】针对香石竹设施栽培土传病害的生物防治技术研究,探讨其根际土壤微生物与枯萎病害的关联性。【方法】采集香石竹健康植株与枯萎病植株根际土壤,采用不同培养基进行分离、纯化,并对分离菌株提取基因组DNA,用其16S rRNA序列的通用引物进行PCR扩增,进行blast同源分析。【结果】从采集样品中分离出的菌株分布于细菌域(Bacteria)中的4个门(Phyla)共15个属(Genera),其中从健康植株组土壤中培养出65株菌,分布于9个属,并以芽孢杆菌(Bacillus)、链霉菌(Streptomyces)及孢霉菌(Mortierella)为优势菌群;而枯萎病株组土样共培养出33株菌,分布于12个属,并且寡养单胞菌(Stenotrophomonas)、鞘氨醇杆菌(Sphingobacterium)、假单胞菌(Pseudomonas)、金黄杆菌(Chryseobacterium)、拟无枝菌酸菌(Amycolatopsis)及尖镰孢病原菌(Fusarium oxysporum)属的分离菌株仅从病株组土壤中分离到;分离菌株同源性在90%-98%的潜在新种(potential novel species)有13株。【结论】研究结果表明,根际土壤中真菌数与总菌数的百分比或Bacillus类群多样性的丰度,可作为评价区域香石竹种植土壤健康状况、栽培土壤演变及病害防治预测预报的参考指标。

[Objective] To investigate the relationship between microbial community and the blight diseases in rhizosphere of carnation for biological control.[Methods] Bacterial strains isolated from the rhizosphere of healthy and blight carnation plants in greenhouse were replicated by morphology and 16S rRNA gene similarity,and investigated by using phylogenetic analysis based on 16S rRNA gene sequence alignments.[Results] Isolates belonged to 4 phyla of bacteria,65 isolates from the samples of healthy carnation plants belonged to 9 genera and Bacillus,Streptomyces,Mortierella were the dominant bacteria.However,33 isolates from the samples of blight carnation plants belonged to 12 genera and Stenotrophomonas,Sphingobacterium,Pseudomonas,Chryseobacterium,Amycolatopsis and Fusarium were only isolated from the sample of blight carnation plants.At least 13 isolates should represent potential novel species based on lower similarities of 16 S rRNA gene（90%-98%）.[Conclusion] The result showed that either the percentage of the fungus in the total strains or the abundance of Bacillus groups in the total strains can be the referential targets to evaluate whether the carnation soil would be healthy for the carnational growth or lead to fusarium wilt diseases,accurately forecasting potential risks of the disease.