IDENTIFICATION OF DICKEYA DADANTII AS A CAUSAL AGENT OF BANANA BACTERIAL SHEATH ROT IN CHINA
Q. Liu, W. Xiao, Z. Wu, S. Li, Y. Yuan, H. Li
Banana bacterial sheath rot is a new disease causing significant economic losses in banana production in China. Pathogenic bacteria infect the middle and bottom parts of the leaf sheath and produce black and brown spots. These spots lead to folding and bending of the sheath, drooping of leaves, and eventual browning and rotting of the entire leaf sheath. In this work, twenty representative strains from five different provinces in China were confirmed by Koch's postulates, and two of them (XJ5-1 and XJ5-2) were characterized by morphological, physiological, biochemical, and molecular assays. Results showed that the strains were more similar to Dickeya dadantii and were less related to Dickeya paradisiaca and Dickeya zeae based on several phenotype characteristics. Phylogenetic analysis and comparison of strains from banana and Dickeya spp. were performed using concatenated partial sequences of the seven housekeeping genes dnaJ, dnaX, gyrB, recN, fusA, gyrA and recA, indicating that the strains isolated from banana-sheath-rot tissues were closely related to D. dadantii and distinct from other Dickeya spp. Therefore, the banana pathogen was determined to be D. dadantii. This report is the first one on the banana-sheath-rot disease caused by D. dadantii in China.