---

期 刊 ：植物保护学报 2010年

关键词：红树；内生细菌；鉴定；抗菌活性物质；芒果炭疽病菌；

Keywords:mangrove, endophytic bacterium, identification, antibacterial activity, Colletotrichum gloeosporioides,

摘 要 ：为了解红树内生细菌AmS2菌株对芒果炭疽菌的抑菌机制及其分类学地位,采用生长速率法测定了菌株抗菌活性对芒果炭疽菌菌丝生长及孢子萌发的有效中浓度(EC₅₀)。结果表明:经形态与培养特征观察、生理生化测定及16S rDNA序列分析,将AmS2菌株鉴定为解淀粉芽孢杆菌Bacillus amyloliquefaciens。抗菌活性物质分析发现,菌株可分泌产生易溶于水和甲醇等强极性溶剂、对热稳定、pH 4~7条件下较稳定的非蛋白类抗菌活性物质。毒力测定表明,菌株抗菌物质粗提物对芒果炭疽病菌菌丝生长和分生孢子萌发的EC₅₀分别为0.9772mg/mL和1.9027mg/mL,当提取物浓度≧3.0mg/mL时,可致使病菌分生孢子壁消解。

Abstract:In order to understand bacteriostatic mechanism of mangrove endophytic bacteria AmS2 strain to Colletotrichum gloeosporioides and its taxonomic status, growth rate method was used to test the effective concentration (EC₅₀) of antibacterial activity on mycelial growth and spore germination. The result showed that the strain AmS2 was identified as Bacillus amyloliquefaciens using the methods of morphology, culture feature observation, physiological and biochemical characteristics determination, and 16S rDNA sequences assay. The antifungal activity of AmS2 fermentation broth was found to keep stable at 100℃ for 30min, and pH 4 to 7 for 12h. The antifungal substance of AmS2 was soluble in water and methanol. The EC₅₀ values of antifungal extract of AmS2 were 0.9772 and 1.9027mg/mL on mycelial growth and conidium germination of C.gloeosporioides MG-1 respectively. The extract could degrade the conidial cell wall of C.gloeosporioides MG-1 at 3.0mg/mL.

---