从栽培海区采回的发病条斑紫菜 (Porphyraeyezoensis)上共分离筛选出 5 1株菌株 ,全部进行人工感染 ,其中 17# 菌株发病症状最典型 ,而感染对照组没有可见变化。初步确定 ,17# 菌株是条斑紫菜绿斑病的主要致病菌。17# 菌株为短杆状、极生单鞭毛可运动的革兰氏阴性菌 ,产生紫褐色色素 ,可水解明胶、酪蛋白、淀粉等大分子物质。葡萄糖氧化发酵试验 (O/F)为氧化性、氧化酶阳性、ONPG反应阳性 ,V -P反应阴性 ,生长需Na+ 等生化特性 ,G +C含量 4 0 .5mol% ,脂肪酸主要成分为C17∶1ω8c和C16∶1ω7c。基于 16SrRNA的系统进化分析均表明 ,从患绿斑病的条斑紫菜叶状体上分离到的致病菌株 17# 与柠檬假交替单胞菌 (Pseudoalteromonascitrea)为同种的不同菌株 Fifty-one isolates were isolated from the diseased Porphyraeyezoensis collected from the cultivation area and all of them were infected by artificial infection. Among them, the symptoms of the 17 # strains were the most typical, but there was no visible change in the infected control group. Preliminary identification, 17 # strains of green spot disease green spot disease is the main pathogen. 17 # strain is short rod-shaped, polar single flagella can move the gram-negative bacteria, resulting in purple brown pigment, hydrolyzable gelatin, casein, starch and other macromolecular substances. Glucose oxidative fermentation test (O / F) was oxidative, oxidase positive, ONPG positive reaction, negative V-P reaction, the growth needs Na + and other biochemical characteristics, G + C content of 40.5 mol%, the main component of fatty acids C17: 1ω8c and C16: 1ω7c. Phylogenetic analysis based on 16S rRNA indicated that the 17 # isolates from Pseudomonas solanacearum and the Pseudoalteromonas citrea were the same isolates