Erwinia

Erwinia is a genus of Enterobacteriaceae bacteria containing mostly plant pathogenic species which was named for the first phytobacteriologist, Erwin Frink Smith. It is a gram negative bacterium related to Escherichia coli, Shigella, Salmonella and Yersinia. It is primarily a rod-shaped bacteria. A well-known member of this genus is the species E. amylovora, which causes fireblight on apple, pear, and other Rosaceous crops. Erwinia carotovora (also known as Pectobacterium carotovorum) is another species, which causes diseases in many plants. These species produce pectolytic enzymes that hydrolyze pectin between individual plant cells. This causes the cells to separate, a disease plant pathologists term bacterial soft rot.