一株番茄青枯菌拮抗菌的鉴定及抗病效果初探

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

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%。

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%