苹果根际自毒物质降解菌的筛选鉴定及降解特性研究

Isolation, identification and degradation characteristics of apple rhizosphere autotoxicitic compounds-degrading bacteria

摘要:

【目的】从苹果根际土壤筛选苹果根系自毒物质降解细菌，并探究分离菌株对根皮苷、邻苯二甲酸、对羟基苯甲酸以及焦性没食子酸的降解能力。【方法】分别采用邻苯二甲酸、焦性没食子酸为唯一碳源富集并筛选其降解菌株。通过对分离菌株的生理生化特征测定及16S rRNA基因序列分析，采用MEGA 5构建系统发育树，进行菌株鉴定。采用紫外分光光度法和高效液相色谱法测定分离菌株对4种自毒物质的降解能力。【结果】共分离5株有降解能力的细菌，编号为BL1、BL2、BL3、BJ1和BJ2，经鉴定BL1为钩虫贪铜菌Cupriavidus necator，BL2为生脂固氮螺菌Azospirillum lipoferum，BL3为氧化烃微杆菌Microbacterium hydrocarbonoxydans，BJ1为Paenibacillus phyllosphaerae，BJ2为Ochrobactrum cytisi。BL1、BL2、BL3菌株对邻苯二甲酸、对羟基苯甲酸、根皮苷、焦性没食子酸的降解率均高于50%。其中BL2菌株的降解效果最好，分别达到66%、72%、84%和84%。【结论】首次发现钩虫贪铜菌、生脂固氮螺菌和氧化烃微杆菌对4种自毒物质均具有很好的降解能力，对缓解自毒物质引起的连作障碍具有潜在的应用价值。

Abstract:

[Objective] The aim of this study was to screen autotoxicitic compounds degradation bacteria from apple rhizosphere soil, and investigate the capacity of degradating phloridzin, phthalic acid, P-hydroxybenzoic acid and pyrogallic acid of the bacteria. [Methods] Bacteria were enriched and isolated by the sole carbon source Phthalic acid, Then，the strains were identified by the determination of physiological and biochemical characteristics, as well as 16S rRNA gene sequence analysis. Additionally, the ability of degradating phthalic acid, pyrogallic acid, P-hydroxybenzoic acid and phloridzin using the ultraviolet spectrophotometry and high-performance liquid chromatography. [Results] A total of five bacteria were isolated and named as BL1, BL2, BL3, BJ1 and BJ2, respectively. All of them degraded phthalic acid, pyrogallic acid, P-hydroxybenzoic acid and phloridzin. The five strains BL1, BL2, BL3, BJ1 and BJ2 were identified as Cupriavidus necator, Azospirillum lipoferum, Microbacterium hydrocarbonoxydans, Paenibacillus phyllosphaerae and Ochrobactrum cytisi respectively. The degration rates to phthalic acid, pyrogallic acid, P-hydroxybenzoic acid and phloridzin of BL1, BL2 and BL3 were all more than 50%. The degradation rate to phthalic acid, pyrogallic acid, P-hydroxybenzoic acid and phloridzin of BL2 was highest, and the degradation rate was 91%, 72%, 84% and 84% respectively. [Conclusion] We firstly discovered that Cupriavidus necator, Azospirillum lipoferum and Microbacterium hydrocarbonoxydans had the ability to degrade those four autotoxictic compounds, and they were expected to be applied in continuous cropping obstacle caused by autotoxicitic compounds in apple.