党参内生细菌荧光假单胞菌RHBA17生物学特性及其对宿主的促生作用

Growth-promoting properties of Pseudomonas fluorescens RHBA17 and its effect on Codonopsis pilosula

【目的】为探究荧光假单胞菌RHBA17的生理特性和对党参促生能力。【方法】从党参根部组织中分离出一株内生细菌,对其菌落形态和显微形态特征进行观察,运用生理生化,16S rRNA分子生物学对菌株进行鉴定,并对其螯合铁载体能力、产IAA能力、合成生物被膜能力、解磷能力、产酶特性等方面进行分析。【结果】分离到的菌株经鉴定隶属于假单胞菌科荧光假单胞菌属(Pseudomonas fluorescens),命名为荧光假单胞菌RHBA17(P.fluorescens RHBA17)。菌株RHBA17最适生长温度为25℃,最适pH为7.0,能在0%~11%NaCl范围生长。此外该菌株还具有很好的溶磷作用,可以产蛋白酶、淀粉酶和木聚糖酶,在高盐、强碱环境中具有产IAA能力且具有较高活性,这些结果说明菌株RHBA17具有较好的促进植物的生长能力。盆栽实验结果表明,RHBA17菌株显著增加了党参的根长和根鲜重,与CK组相比,株高提高了16.05%和9.43%,根长提高了7.69%,根鲜重提高了12.92%。【结论】菌株RHBA17具有较强的耐碱性,耐盐性,对恶劣环境也有一定的抵抗能力,能促进党参的生长。为进一步开发研制党参促生菌剂或微生物有机肥提供资源,为菌株RHBA17在农业生产中的应用提供了理论依据和实验基础。

【Objective】The study aimed to investigate the physiological characteristics and the growthpromoting ability of Pseudomonas fluorescens RHBA17 on Codonopsis pilosula.【Method】In this study,an endophytic bacterium was isolated from the root tissue of Codonopsis pilosula,and its colony morphology and micromorphological characteristics were observed.The strain was identified using physiological and bio⁃chemical methods,16S rRNA molecular biology,and its ability for iron chelation,indole-3-acetic acid(IAA)production,biofilm synthesis,phosphorus decomposition,and enzyme production were analyzed.【Result】The isolated strain was identified as Pseudomonas fluorescens RHBA17,which exhibited optimal growth at 25℃and pH 7.0,and demonstrated tolerance to the range of 0%to 11%NaCl.Moreover,the strain exhibited efficient phosphorus solubilization,as well as the production of protease,amylase,and xyla⁃nase.It also demonstrated the ability to produce IAA and exhibited high activity in high salt and strong al⁃kali environments.These findings indicated that strain RHBA17 possessed significant plant growthpromoting capabilities.In a pot experiment,the RHBA17 strain significantly increased the root length and root fresh weight of Codonopsis pilosula.Compared to the control group,the plant height increased by 16.05%and 9.43%,root length increased by 7.69%,and root fresh weight increased by 12.92%.In sum⁃mary,strain RHBA17 exhibits strong alkali and salt resistance,as well as tolerance to harsh environments,making it a suitable candidate for promoting the growth of Codonopsis pilosula.【Conclusion】This study provides valuable resources for the development of growth-promoting agents or microbial organic fertilizers for Codonopsis pilosula and establishes a theoretical and experimental foundation for the application of strain RHBA17 in agricultural production.