The effect of high copy effector eop1 in Ewrinia tracheiphila
The cucurbits (family Cucurbitaceae) are an important plant family that includes squash, cucumbers, pumpkins, muskmelons, gourds, and watermelons. Bacterial wilt disease primarily affects cucumber and melon, though it may also affect pumpkin, squash, and zucchini. Erwinia tracheiphila is the bacterium that is responsible bacterial wilt. Bacterial wilting disease is a problem throughout the eastern half of the U.S. because it causes widespread damage and expensive in crop loss. The insect vectors, striped cucumber beetles (Acalymma vittata) and spotted cucumber beetles (Diadrotica undecimpunctata) carry E. tracheiphila in their mouthparts and gut. In early spring the beetles then feed on leaves and in the process deposit the bacteria into the injured leaves through their mouthparts and feces. Most of the research on this economical pathogen has been focused on managing the vector harboring the pathogen. Very little work has been dedicated to understanding the mechanisms that cause disease in this pathogen. E. tracheiphila is a gram negative pathogen similar to many other well studied gram negative plant pathogens. It possesses a hrp pathogenic gene cluster which is known to secrete pathogenicity factors into the host. Recent studies have indicated that the effector eop1 from E. amylovora contributes to host specificity and virulence. E. amylovora is a closely related species to E. tracheiphila phylogenetically and symptomology. The goal in this project is to investigate host-specificity in E. tracheiphila cucurbit interactions and the possible role that eop1 plays in this interaction. Results of a phylogenetic analysis indicate that the tree topology of Eop1 of different E. tracheiphila strains is similar to that of host of which they infect. High copy variation of eop1 was created by cloning eop1 into the high copy vector pBluescriptSK. Extracellular polysaccharide secretion (EPS) test revealed a phenotypic difference in high copy eop1 compared to low copy expression of eop1. The pathogenecity test was unable to demonstrate a difference in virulence between the high and low copy expression of eop1.^
Peter LeRay Prestwich,
"The effect of high copy effector eop1 in Ewrinia tracheiphila"
ETD Collection for Tennessee State University.