烤烟漂浮育苗根系致腐细菌的分离与鉴定

Isolation and Identification of Bacteria Causing Root Rot of Tobacco Seedlings in Floating System

烟草漂浮育苗中,移栽前在育苗池液的烟苗根系常发生腐烂,影响健壮烟苗的培育和移栽后烟苗的成活率。本研究分别从发生根腐的育苗池液和烟苗的腐烂根系采集样品,分离和纯化培养195株细菌,根据分离物细菌的培养特征、显微形态特征初步归类,筛选出28株细菌;进一步测定其致腐性、生理生化特征及16S r DNA基因序列。通过综合分析,鉴定致腐细菌的属种。结果表明,13株细菌具有较强的致腐性,分离纯化鉴定的致腐性菌株分别为5个属中6个种的细菌,分别为枯草芽孢杆菌(Bacillus subtilis),韦氏芽孢杆菌(B.weihenstephanensis),耐寒短杆菌(Brevibacterium frigoritolerans),克氏微杆菌(Microbacterium ketosireducens),罗氏耶尔森氏菌(Yersinia rohdei)和香味类香味菌(Myroides odoratus),这些细菌是引起烟草漂浮育苗过程中烟苗根系腐烂的主要细菌。

Tobacco root systems are often rotted before transplanting in the nursery pond during tobacco floating system. It influences tobacco robust seedlings cultivation and survival rate after transplanting of tobacco seedlings. In this study,samples were collected from the diseased seedlings and the water of nursery pond. 195 bacterium strains were isolated and purified. 28 bacteria were screened according to the cultural characteristics and microscopic morphology of bacteria to determine its saprogenic ability,physiological and biochemical characteristics and16 S r DNA gene sequences. The results showed that 13 strains could strongly cause the root rot of tobacco seedlings,and they were identified as six species of bacteria in five different genera which were Bacillus subtilis,B. weihenstephanensis,Brevibacterium frigoritolerans,Microbacterium ketosireducens,Yersinia rohdei and Myroides odoratus,respectively. These bacteria are the main bacteria that cause the root rot of tobacco seedlings in floating system.