most likely acquired through horizontal gene transfer late in the evolutionary process. Dickeya solani also produces antifungal compounds including oocydin A and the novel compound solanimycin which are thought to help it outcompete fungi. Disease cycle In the spring, primary inoculum can be found in the seed tubers. There are three major steps in the infection process. The pathogen must first be able to adhere to the plant's surface and penetrate it either via a wound or a natural opening such as the stomata. Following penetration, the bacteria invades and then degrades the cell wall. In late spring to the summer the bacteria can spread from the original seed tuber to the developing roots and stems. Dickeya solani can invade quickly and the bacterial cells relay on a cell to cell communication method called quorum sensing. In quorum sensing, the cells communicate with each other via small signaling molecules. The bacterial cells can reproduce in the intercellular spaces and can generate enzymes that degrade or destroy the plant cell wall. Once the cell wall is degraded a liquification of the stem and the original seed tuber occurs. New tubers growing alongside the diseased tuber may become contaminated in the late summer into the early fall. During harvest, mechanical injuries can occur on the tuber which can provide more entry spots for Dickeya solani. The disease can then spread more when the potato tubers are put into storage. Rotten tubers that were discarded can allow for disease dispersal. Dickeya solani can overwinter in soil on plant residues. References External links Type strain of Dickeya solani at BacDive - the Bacterial Diversity Metadatabase Potato diseases Bacteria described in 2014 Bacterial plant pathogens and diseases