巨大芽孢杆菌ZX001的分离鉴定及其与魔芋软腐病发生的关系

为了研究与魔芋软腐病发生相关的土壤微生物，从患软腐病腐烂的魔芋球茎深处分离出1株优势菌株，命名为ZX001。将该菌株的16S rDNA序列与NCBI数据库中的基因序列进行同源性比对分析，结果显示其与巨大芽孢杆菌(Bacillus Megaterium)菌种的亲缘关系最近，序列同源性达到99%以上，结合细胞形态特征、生理生化特征分析结果，将ZX001菌株初步鉴定为Bacillus megaterium。该菌株具有降解和利用魔芋葡甘聚糖的能力。在降解利用魔芋球茎的实验中，该菌株不能在魔芋球茎皮的表面上生长，但能够在魔芋果肉上生长。这些实验结果显示，该菌株不是魔芋软腐病发生的致病菌，但其有可能通过球茎皮上的伤口进入，并产生多种酶降解魔芋果肉，从而加剧魔芋球茎的腐烂，增加魔芋软腐病发生的机会。

Bacillus megaterium Strain ZX001: Isolation and Identification and Its Relationship with Konjac Soft Rot Disease

The paper aims to study the soil microorganism associated with konjac soft rot disease. A dominant strain named ZX001 was isolated from the recesses of rotten corm of Amorphophallus Konjac infected with soft rot disease. We compared the 16S rDNA sequence of the strain with gene sequences in the NCBI database. The results showed that: the gene sequence was closely related to the Bacillus megaterium strain (99%); combined with the results of morphological, physiological, and biochemical characteristics, the ZX001 strain was preliminary identified as a Bacillus megaterium; subsequent experiments showed that ZX001 could not grown on the surface of konjac corm pericarp, but could grown on the sarcocarp of konjac corm, and had the ability to degrade and utilize konjac glucomannan. The results indicate that this strain is not a pathogenic bacterium of the konjac soft rot disease, but it might enter into konjac corm through the wound on the surface of pericarp, and may produce many enzymes to degrade konjac corm sarcocarp, so as to aggravate the decay of konjac corm, and increase the chance of soft rot disease.