土地类芽胞杆菌(Paenibacillus terrae)新菌株NK3-4及其功能

Paenibacillus terrae new strain NK3-4 and its functions

摘要:

【目的】分离筛选出一株能溶解矿物磷、钾、硅，防治作物病害，具有固氮活性的细菌。【方法】从大豆(Glycine max)田中采集大豆根周土壤，用钾长石选择性培养基进行加富培养，从加富培养物中分离具有溶解硅酸盐矿物能力的细菌。采用平板对峙法，从分离到的菌株中筛选出一株对大豆根腐病菌尖孢镰刀霉(Fusarium oxysporum)抑制作用强的菌株，再通过摇瓶培养法测定该菌株溶解矿物钾、硅、磷的能力，用改良阿须贝(Ashby)无氮液体培养基培养待测菌株，测定菌株的固氮功能。依据形态观察、生理生化反应及16S rRNA基因序列分析结果鉴定菌株。【结果】从健康大豆根周分离筛选出一株编号为NK3-4的细菌，该细菌在平皿上对尖孢镰刀霉的抑菌带宽度达到8.0 mm；培养24 h后，含有钾长石的液体培养基中速效钾浓度比培养基中不含钾长石的处理浓度高15.0 mg/L，可溶性硅浓度比不接种对照高51.3 mg/L；在磷酸三钙为唯一磷源的液体培养基中培养8 d后，培养基中可溶性磷浓度是不接种对照的4.8倍；在改良阿须贝液体培养基中培养15 d后，培养基中可溶性氮浓度是不接种对照的4.6倍，每升培养基中菌体氮含量达到12.7 mg。经鉴定，该菌株为土地类芽胞杆菌(Paenibacillus terrae)的新菌株。【结论】NK3-4是一株具有多种生物活性的土地类芽胞杆菌新菌株，可应用于生物农药及生物肥料的研制与开发。

Abstract:

[Objective] The aim of this paper was to obtain a bacterial strain which has the ability of degrading mineral phosphorus, potassium and silicon, controlling plant disease, and fixing nitrogen. [Methods] Soil was collected from rhizosphere of soybean (Glycine max), then selected medium supplemented with potash feldspar was used to enrich bacterial strains exhibiting ability of degrading silicate. Dual-culture plate method was used to gain a bacterium which had the strongest ability of antifungal activity to the soybean root rot pathogen Fusarium oxysporum. After that, the activity of degrading mineral potassium, silicon, and phosphorus of the bacterium was tested by shake flask method, meanwhile the optimized Ashby’s medium was used to test the activity of fixing nitrogen. The isolated strain was identified through morphology observation, physiological and biochemical tests and 16S rRNA gene sequence analysis. [Results] A bacteria strain named NK3-4 was isolated from rhizosphere soil of healthy soybean in field. The bacterium inhibited F. oxysporum growth with inhibiting belt of 8.0 mm width on plate. The concentration of dissoluble potassium in medium contained potash feldspar was 15.0 mg/L higher than that in medium without potash feldspar, and the concentration of dissoluble silicon was 131.7% higher than the un-inoculated control after cultivation for 24 hours. The concentration of dissoluble phosphorus was 4.8 times of the un-inoculated control in medium with calcium phosphate as only phosphoric source after cultivation for 8 days. The concentration of dissoluble nitrogen was 4.6 times of the uninoculated control in Ashby’s medium after cultivation for 15 days, and the nitrogen content fixed in the bacterial organism was 12.7 mg in one liter of medium. The identification showed that the NK3-4 strain was a new strain belongs to Paenibacillus terrae. [Conclusion] Strain NK3-4 is a new strain of P. terrae with multifunctions, it can be used as a potential microorganism for exploit of biofungicide and biofertilizer.