| 摘要: |
| 【目的】探究丛生盔形珊瑚共附生放线菌NLG-3对植物病原菌的抑菌活性，对其分类地位进行鉴定，为丛生盔形珊瑚共附生放线菌的开发利用提供依据。【方法】采用平板对峙法测定NLG-3对12种植物病原真菌的抑菌活性；采用滤纸片法测定NLG-3发酵液乙酸乙酯粗提物对5种病原细菌的抑菌活性；通过改变pH、温度及光照条件，测定该菌株发酵液的稳定性；采用几丁质平板培养法测定该菌株产几丁质酶的能力；通过基因扩增检测该菌株是否含有非核糖体多肽合成酶（NRPS）和聚酮合成酶（PKS）基因；结合菌株形态特征、生理生化特性及16S rDNA序列分析对该菌株进行分类鉴定。【结果】菌株NLG-3具有广谱抑菌活性，对供试病原真菌均有不同程度的抑制作用，其中对香蕉炭疽病菌（Colletotrichum musae）和胶孢炭疽病菌（C. gloeosporioides）的抑菌率均在85%以上。NLG-3发酵液乙酸乙酯粗提物可以明显抑制蜡样芽孢杆菌（Bacillus cereus）的生长，1 mg/mL NLG-3发酵液乙酸乙酯粗提物对蜡样芽孢杆菌的抑菌圈直径达（2.20±0.11） cm。NLG-3发酵液在中性(pH=7)条件下抑菌活性突出，经40 ℃及以上高温处理其活性丧失，光照对其抑菌活性无影响。NLG-3能产生几丁质酶，分解培养基中的几丁质。该菌株具有合成酶基因PKSⅡ和NRPS，经初步鉴定该菌株为白刺链霉菌（Streptomyces albospinus）。【结论】NLG-3抑菌活性较好，具有潜在防治热带植物病害的应用价值。 |
| 关键词: 丛生盔形珊瑚 共附生放线菌 抑菌活性 植物病原菌 |
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| 基金项目:海南省高等学校科学研究资助项目（Hnky2017ZD-2）；海南省重点研发计划项目（ZDYF2018230） |
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| Antibacterial activity and identification of epiphytic actinomycete NLG-3 from Galaxea facicularis |
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ZHANG Siying,CHEN Yufeng,LUO Yanping,et al
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| Abstract: |
| 【Objective】This study explored the antibacterial activities of epiphytic actinomycete NLG-3 from Galaxea facicularis against plant pathogen and identified its classification to provide evidence for its development and utilization.【Method】The antifungal activities of NLG-3 were determined against 12 tropical plant pathogenic fungi by plate confrontation method.The antibacterial activities of ethyl acetate extract of NLG-3 fermentation broth against five pathogenic bacteria were determined by filter paper method.The stability of fermentation broth was determined with changing pH,temperature and light conditions.The produced chitinase was determined by chitin plate culture method.Gene amplification was used to confirmed whether non ribosomal polypeptide synthase (NRPS) and polyketide synthase (PKS) were contained.The strain was identified based on morphology,physiological and biochemical characteristics as well as 16S rDNA sequence analysis.【Result】The strain NLG-3 showed broad activities against tropical plant pathogenic fungi with different inhibition degrees.The inhibition rate against Colletotrichum musae and C. gloeosporioides was above 85%.The ethyl acetate extract significantly inhibited the growth of Bacillus cereus.The diameter of inhibition zone by 1 mg/mL NLG-3 against Bacillus cereus was (2.20±0.11) cm.The fermentation broth of the strain showed excellent antifungal activity under neutral conditions (pH=7),the activity was lost above 40 ℃,and light had no effect.NLG-3 produced chitinase,which decomposed chitin in the medium.The strain had the synthase genes PKS Ⅱ and NRPS,and was identified as Streptomyces albospinus.【Conclusion】NLG-3 showed excellent biological activity and had potential for preventing tropical plant diseases. |
| Key words: Galaxea facicularis epiphytic actinomycetes antibacterial activity tropical plant diseases |
