荧光假单胞菌CZ菌株定殖及抗病毒活性研究

荧光假单胞菌Pseudomonas fluorescens CZ能分泌包括碱性磷酸酶在内的抗病毒蛋白抑制烟草花叶病毒Tobacco mosaic virus(TMV)侵染?本文利用抗生素利福平逐级诱导获得抗药性标记菌株CZ-rif, 生测试验显示:野生型和抗药型菌株的发酵上清和粗蛋白液对TMV的体外钝化效果均大于90%, 无显著差异?灭菌和非灭菌的根际土拌CZ-rif菌液后盆栽烟苗, 取根际土在含抗生素的平板上检测定殖菌量, 结果显示, CZ-rif能够在烟株根际土壤中有效定殖, 第31天在灭菌土中的定殖菌量为4.3×104 cfu/g, 显著大于在非灭菌土中的定殖菌量6×103 cfu/g, 在叶面上的定殖菌量显著低于根际土壤?叶面喷施CZ-rif菌液后24 h接种病毒, 对TMV-GFP的预防效果为45.85%?田间试验中喷淋菌株发酵稀释液, 对烟草花叶病毒病的防效为42.02%?此外, 水培试验显示生防菌发酵液对烟草幼苗具有促生作用?总之, 荧光假单胞菌CZ能在烟草根际定殖和促进植株生长, 叶面喷施能钝化TMV并抑制其初侵染, 可以研发防治病毒病害的生物制剂?

Colonization of Pseudomonas fluorescens strain CZ and its antiviral activity

Pseudomonas fluorescens CZ can secrete antiviral proteins including alkaline phosphatase to inhibit the infection of Tobacco mosaic virus (TMV). The resistant strain named CZ-rif was obtained by inducible screening and culture with antibiotic rifampicin. Both wild type and resistant strain could produce antiviral proteins to remarkably inactivate TMV in vitro with an efficiency of above 90%, showing no significant difference. In colonization experiments by planting tobacco in sterilized or unsterilized soil mixed with CZ-rif bacteria, the population of colonizing bacteria in rhizosphere soil was checked by using the colony-counting method on plates with antibiotics. The results showed that CZ-rif could colonize the tobacco-planted soil. The population in unsterilized soil was 4.3×104 cfu/g, higher than that in sterilized soil (6×103 cfu/g) at 31 d. The population on the tobacco phylloplane was lower than that in the soil. Spraying bacteria could suppress TMV-GFP infection by 45.85% at 24 h. In field experiments by showering with bacteria fermentation, CZ had an inhibition effect of 42.02% against plant viruses. Furthermore, in water planting experiments, CZ fermentation broth could promote tobacco plant growth. In conclusion, P. fluorescens CZ could colonize the tobacco rhizosphere to promote plant growth, and inactivate TMV to suppress virus initial infection, showing the potential as a biological agent.