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利用梯度稀释和对峙试验的方法,从向日葵根际土壤筛选到18株对向日葵菌核病病原菌—核盘菌(Sclerotiniasclerotiorum)有拮抗效果的细菌,其中1株具有较强的拮抗效果,命名为XRK4。经过形态观察及16S rDNA序列分析,将XRK4鉴定为地衣芽孢杆菌(Bacillus licheniformis)。研究表明XRK4具有β-1,3-1,4-葡聚糖酶活性。设计引物以XRK4的基因组DNA为模板扩增得到长度为732 bp的β-1,3-1,4-葡聚糖酶的完整基因,其开放阅读框架编码243个氨基酸。XRK4可能因产生葡聚糖酶,降解病原菌细胞壁而具有拮抗活性。
By means of gradient dilution and confrontation test, 18 strains of bacteria that antagonized the pathogen Sclerotinasclerotiorum of sunflower were screened from the rhizosphere soil of sunflower, and one of them had a strong antagonistic effect named XRK4 . After morphological observation and 16S rDNA sequence analysis, XRK4 was identified as Bacillus licheniformis. Studies have shown that XRK4 has β-1,3-1,4-glucanase activity. Primers were designed to amplify a 732 bp β-1,3-1,4-glucanase gene using XRK4 genomic DNA as a template. The open reading frame (ORF) encoded 243 amino acids. XRK4 may have antagonistic activity by producing glucanase and degrading the cell wall of pathogenic bacteria.