First report of potato blackleg disease caused by Pectobacterium atrosepticum in Guangdong China.
In 2013, diseased potato plants exhibiting blackleg and soft rot symptoms were found in the winter potato production areas of Huizhou city, Guangdong Province, China, with an incidence of approximately 20%. Initially, the stem bases of infected plants blackened and this symptom spread upward. Later, the foliage of the diseased plants became yellow and the stem rotted with vascular discoloration. Twenty diseased plants with typical black leg symptoms were collected from a 10-ha potato field. A bacterium with small, irregular, round, fluidal, white colonies was isolated from the vascular tissue of all diseased plants on nutrient agar. Ten strains were randomly selected for pathogenicity assays. Using the universal bacterial 16S rDNA primer set, 1400-bp fragments were amplified from the 10 strains. The sequences of the 10 fragments were identical and had 100% sequence identity with the 16S rDNA of P. atrosepticum CFBP 1526 (JN600332). The 438-bp and 690-bp fragments were respectively amplified from all 10 strains with the P. atrosepticum-specific primers Y45/Y46 and ECA1f/ECA2r. This is thought to be the first report of potato blackleg disease caused by P. atrosepticum in Guangdong.