一株番茄青枯菌拮抗菌的鉴定及抗病效果初探

从形态、生理生化、16S rDNA3个方面确定了番茄青枯菌拮抗菌株3-1-16的分类地位。光学显微镜下观察到菌体为杆状细胞,革兰氏染色均匀,并可见菌体染成蓝紫色。透射电镜进一步观察到细胞内有许多颗粒状物质,无伴胞晶体。Biolog鉴定,3-1-16与巨大芽孢杆菌(Bacillus megaterium)具有最高相似率为98%。16S rRNA分析,3-1-16与巨大芽孢杆菌MO31同源性最高为99.4%。聚类分析显示3-1-16与3株巨大芽孢杆菌聚成一支,支持度为100%。生理生化特征及培养特征测定结果表明,菌株3-1-16鉴定为巨大芽孢杆菌(Bacillus megaterium)。盆栽试验表明该菌株对番茄青枯病防病效果达到81.3%。

Identification of an Antagonistic Bacterium Against Ralstonia solanacearun and Primary Study of Effect on Disease Resistance

On the basis of morphological, physiological and biochemical characters as well as sequence analysis of 16S rDNA, the antagonistic bacterium strain 3-1-16 was identified. Under optics microscope, the strain was bacilliform, G~ , stained evenly purple. Furthermore, many granulose structures were found in cell without parasporal crystal under EM observation. According to Biolog Bacteria Identified system, 3-1-16 strain has 98% similarity with Bacillus megaterium MO31. A 1443-bp 16S rRNA gene sequence was obtained from strain 3-1-16. The BLAST search of the GenBank database using this sequence showed its similarity to many species of Bacillus. It was 99.4% similar to the 16S rRNA gene sequence of Bacillus megaterium strain MO31 (GenBank accession No. AY553118.1) over 1437 bases. Phylogenetic tree of Bacillus 16S rRNA gene sequences showed that 3-1-16 strain was clusterred with three Bacillus megaterium. Based on those characteristics, strain 3-1-16 was identified as Bacillus megaterium GIMA 1.001. Glasshouse trials demonstrated that the control efficiency of 3-1-16 strain against tomato bacterial wilt disease was 81.3%