条斑紫菜褐斑病原褐藻酸降解菌的筛选与鉴定

Screening and Identification of Pathogenic Alginic Acid Decomposing Bacteria from Porphyrae yezoensis

对分离自条斑紫菜(Porphyrae yezoensis L.)褐斑病的1株能够分解褐藻酸的假交替单胞菌(Pseu-doalteromonas sp.)Z2进行了致病性、形态特征、生理生化特性及16 S rRNA与gyrB基因序列的系统发育学分析等研究。结果表明,该菌能够使条斑紫菜出现红斑,为革兰氏染色阴性杆菌,有动力,氧化酶阳性,严格需氧,生长需要Na+,大小约在(1.0～1.2)μm×(2.0～2.5)μm;其16 S rRNA和gyrB基因序列通过Blast检索均与假交替单胞菌属(Pseudoalteromonas)细菌具有较高的同源性,gyrB基因序列与产黑假交替单胞菌(Pseudoalteromonas nigrifaciens)同源性在99%,综合分离菌的形态、生理生化特性及16 S rRNA和gyrB两种基因的分子鉴定,确认分离菌为假交替单胞菌,且初步认为其可导致紫菜发生褐斑病。

The pathogenicity, morphological, physiological and biochemical characteristics of Pseudoalteromonas sp. isolated from Porphyrae yezoensis exhibiting brown spot disease were determined. Its 16 S rRNA and gyrB gene were sequenced; and the phylogenetic trees based on 16 S rRNA and gyrB sequences were constructed. The results showed that the isolated bacte- ria could caused brown spot of Porphyrae yezoensis, the isolated bacteria （Z2） was Gram-negative rod, positive for motility, positive for oxidase, aerobic, （1.0~1.2） l.~mx（2.0-2.5） I.Lm in size, Na~ was essential for its growth; and the 16 S rRNA and gyrB genes all exhibited high similarity to those of Pseudoalteromonas sp. from GenBank database. The isolated strain （Z2） was identified as Pseudoalteromonas sp. based on morphological, physiological and biochemical characteristics, and molecular indentification of 16 S rRNA and gyrB genes, and the isolated bacteria （Z2） was preliminary regarded as the pathogen of brown spot disease of Porphyrae yezoensis.