Soft rot of potatoes caused by Bacillus amyloliquefaciens in Guangdong province, China

Abstract

Potato tubers exhibiting symptoms of soft rot were observed in a field in Baiyun District, Guangzhou, Guangdong Province, China, in March 2016. Bacteria were isolated from the diseased potato tubers. Using morphological and molecular (16S rDNA and gyrB) characterization and pathogenicity tests, a representative isolate of the bacterium was identified as Bacillus amyloliquefaciens. Inoculating the isolate onto healthy potato tubers led to soft rot with the same symptoms as displayed in the field, which confirmed Bacillus amyloliquefaciens as the causal agent. Further testing of the bacterial isolate on other hosts showed that it could also cause soft rot on tomato, onion and pepper. To our knowledge, this is the first report of soft rot of potato tubers caused by Bacillus amyloliquefaciens in the field.